Introduction: Teardrop Trailer - Boxes Within a Box
Second Prize in the
Make a Box Contest
About 10 years ago I saw my first teardrop trailer and was really impressed. I've been camping for nearly 50 years (tenting, trailer camping, and backpacking with my parents and car camping/backpacking with my wife and children) and I though one would be perfect for low impact car camping without having to set up and tear down a tent on a daily basis on a long trip.
The real impetus for this project was a desire to take my children on a vacation across the USA and to visit 18 - 20 national parks over a 40 day window (Photo 1).
With the teardrop trailer you have a good solution - small enough to get through tight spaces (Photos 2,3,4,5,6) while large enough to provide some comfort and independence for more than a day or three.
Before I began design and construction I sat down and thought about what features I wanted in the camper and how I was going to use it.
As your typical geek - I needed to start with capturing the requirements:
- Trailer had to be large enough for a full-size fulton mattress to fit in (if I'm going to build it, I at least want it to be comfortable to sleep in).
- Didn't want it so small that we felt claustrophobic if we were trapped in it for the better part of a day due to bad weather (Photos 7,8 - California redwoods) .
- Wanted decent airflow through the unit and insulation to provide some noise reduction from outside noises and to slow down temperature swings on the inside.
- Wanted the camper part to be removable from the flatbed trailer so the trailer could be used for other things if necessary.
- Wanted everything to run from 12 VDC, but also wanted a couple of 120 VAC outlets and a battery charger available if AC power was available.
- Wanted LED lighting - low power consumption and they don't break as easily as regular lights when subjected to shock and vibration.
- Wanted a functional kitchen/galley with a decent prep counter-top (we have tent camped for years and I really dislike doing food prep on picnic tables - they work but...) - (Photos 9,10,11,12)
- Wanted sufficient space to store all the cooking gear, a cooler, 12 gallons of water, and storage for food (Photo 9)
- Wanted a stove (reuse my trusty Coleman propane stove) (Photo 10)
- Wanted a gas grill (Photo 11)
- Needed a "sink/washbasin area - but decided against a full up sink, drain, water pump implementation - it would take up a lot of space that can't be used for storage (Photo 11)
- Wanted storage in the cabin area - his, hers', ours'
- Camper needed to be sturdy enough to handle some fairly rough off-road bouncing around without getting damaged (Photos 2,3,4,5,6)
- Wanted the top of the camper to be sufficiently strong to support a roof rack to haul kayaks or a rocket box if necessary.
- Wanted an aluminum bodied trailer instead of a steel one. Provides for corrosion resistance, strength, and light weight (Photo 13)
- Wanted space in front of camper (2' to 3') to be able to carry 4 bicycles also (Photo 13).
- Wanted doors that had good locks and windows that could open with screens to provide airflow (Photos 1,13,14)
- Wanted a roof vent in the cabin area with a fan (12 VDC)
- Seriously though about Solar Cells - decided against them at this time,
- Seriously looked at deep cycle batteries but decided that two pickup truck batteries that were compatible with my truck would let me swap out batteries as necessary to recharge them while driving down the road using the truck alternator.
- Wanted a space for a fire extinguisher.... Hey - I'm cooking with propane!
- Was very concerned about structural integrity - shock and vibration does a lot of damage to things not designed to handle it.
- Wanted it to be able to handle the weather - hot, cold, wet, and dry. (Photos 7,8).
I began by creating paper sketches for the camper in December, finalized the drawings by February and began building the camper in March. Construction was finished in late May and we took it out over the Memorial Day weekend for a shake down trip. We returned from the Memorial Day trip and I made a series of tweaks to the camper over the next couple of weeks.
In the middle of June I packed up the kids, the wife, the kitchen sink and broke the trailer in properly - a 9991 mile trip around the USA visiting multiple national parks - some nights staying at commercial campgrounds while other nights were only lit by the trailer LED lights and the stars.
Step 1: Creating the Design
I began the project by looking at the photos of many teardrops published on the internet, at the many plans published in the 40's and 50's by Popular Mechanics, and finally by visiting a couple of travel trailer dealers that sell commercially made units.
The trailers the dealers had were nice but were generally spartan and lacked the custom features that a home-made trailer has.
I was also very tempted to purchase one of the detailed construction plans that can be purchased by multiple vendors on the internet that walk you through each step to make the trailer - but in the end I decided to design and build my own.
I started out by creating a number of hand drawings of potential shapes and sizes and modified them as I began to resolve my requirements. I measured the cooler I wanted to haul in the back and measured the futon mattress that would go in the cabin to get the minimum interior dimensions.
I had a difficult time deciding on the trailer bed size - 7' x 14' or a 6' x 12' bed. The more I thought about it and laid things out on paper as well as adding the total trailer length and the length of the truck I was going to tow with, the more I realized the 7' x 14' trailer would be too large for some of the places I wanted to go and the 6'x12' trailer was the more cost effective and versatile solution (for instance Zion NP has trailer size limitations).
To get an idea of the final physical size, I cut some 1" wide x 1/8" thick x 96" strips of from pine wood and used the wood strips and duct tape to create a physical outline of the desired frame (width, length, height) on my patio and used this outline to firm up the design.
In the end, camper was 71-1/2" wide, 108" long, and 60" high. The major drawback of selecting this size of a camper from a construction perspective - sheets of plywood are 48" x 96" so I couldn't just use a single sheet of plywood anywhere - this drove the cost up a little and also added to complexity of the build.
I tried to scan the drawings I made for the cabin but the contrast was really bad - green engineering paper and mechanical pencil doesn't hold up well over a few months of using them for reference.
If you haven't already done it check out the teardrop trailers by e1ioan or HaleyP5 - they are great! There are several custom things they did that I would have loved to incorporate into my design - if I would have thought about it. That is half the fun of building your own teardrop - you can customize it to your own needs or desires.
Once I knew the design, I could begin purchasing the necessary materials... but first some thoughts on the construction of the camper.
Step 2: Thoughts on Construction
In this section I thought I'd provide some commentary on the construction - skip this section if you are just interested in looking at the construction steps.
- This isn't a project for the faint of heart - you will build a box with complex curves, insulation, electricity, and it must survive vibrations and the elements. It requires the use of a fairly decent woodshop and all the tools necessary for general construction.
- I tried to create this Instructables with a logical reading flow for the construction process - section by section, step by step. To actually construct this teardrop trailer, there is a lot moving between the sections during the construction.
- The internet is great for finding the materials you need - before heading to the local hardware stores (Home Depot, LOWES, Tractor Supply) I would always check their inventory on hand so I didn't waste a trip.
- For all the things the local hardware stores didn't stock or were easier to get via direct shipment I used the following companies extensively (in alphabetical order): Amazon.com, HarborFreight.com, McFeeley.com, Rockler.com, Teardroptrailerparts.com, Zoro.com,
- I estimate the weight of the camper to be less than 400 lbs. empty - I can lift the front about 6" by hand to get supports under it. The back is heavier and I need a short lever to get it off the concrete pad.
- Everything was glued and screwed or I used an air nailer when appropriate. Nothing was ever glued without secondary fastening and all secondary fastening had glue applied. Also, everything that was screwed together was pre-drilled with an appropriate pilot drill bit and countersunk before glue was applied.
- Screws: Used a variety of #6,#8, #10 screws - round head & flat head. Also a selection of stainless steel screws for exterior work. I purchased the screws used for construction from http://www.mcfeelys.com and purchased an assortment of Kreg cabinetry screws from www.rocker.com.
- Glue: Exterior wood glue for everything - I used Titebond and Gorilla
- I really like the look of wood, especially wood with character, so the interior of the camper would be sealed - no stain or paint on the interior. I wanted the cabinetry in the kitchen/galley area and in the sleeping area to look nice, so I decided to make the frames and doors out of cherry - fortunately I had a couple hundred board feet of rough cut cherry in the lumber pile.
- For the exterior, I wanted an exterior color that looked nice, would hide all the little mistakes I knew I would make, and didn't clash with the color of my truck. Really thought hard about the aluminum exterior that so many teardrop have, but having never worked with big sheets of aluminum was afraid of screwing it up. I also considered fiberglassing the exterior - but didn't want to have to deal with the odor in my garage.
- I chose to use a marine grade epoxy as the sealer and then coated the camper with two coats of an exterior grade metallic paint. The marine grade epoxy and metallic paint worked wonderfully - except at the joints where the sheets of plywood came together. All the shaking and vibration from the trip across the USA created microscopic hairline cracks and by the time we were headed home from the trip I was spreading caulk across a number of fine cracks (OSI QUAD is a fabulous product). In the end though, water got in a seam and the 1/4" plywood I used for the exterior wall acted like a sponge.
- Since then I've removed the damaged panels, remounted them (screw & glue), and coated the trailer with fiberglass and resin.
Cost to build the camper:
- Flatbed trailer - 6' x 12' - $2500 - much higher than purchasing a trailer from Harbor Freight or a standard steel trailer but I wanted aluminum so it wouldn't rust, be lighter than an equivalent steel trailer, and would be strong enough to handle some serious off-road use - with and without the camper.
- Cabin doors - I purchased pre-made doors from: http://teardroptrailerparts.com They were responsive and the received product was of excellent quality. They ran about $300 each.
- All the rest (see the parts list on the next page) ran somewhere between $1000 and $1500.
- Not real inexpensive but less than the $8k to $10K for a commercially made unit with some customization.
The most difficult parts of the entire construction process were:
- the installation if the interior cabin roof - overhead, tight space, tight curves, and the walls were about 1/8" out of true with each other.
- creation of the back hatch for the kitchen. Maintaining the curvature of the hatch while ensuring the squareness of the hatch during fabrication and glue-up and installing the hatch latches were all challenges.
Step 3: Parts Listing
I can't find the original parts list I created and there were several unplanned trips to the hardware store for additional materials but this is a fairly complete parts list.
If a source isn't provided for the materials then they were purchased from either Tractor Supply, Home Depot, Lowes, or from a sawmill (rough cut oak and cherry boards).
Screws - 1/2", 3/4", 1", 1-1/4", 1-1/2", 2", 2 1/2", 3" - flat head and pan head. Stainless steel for all external use. Countersink all external screw heads. I have no idea how many I used - I purchased a couple 1000 screw assortments - www.McFeeley.com
Kreg™ 675-Pc. Self-Tapping Pocket Hole Screw Kit - www.Rockler.com
Variety of sanding disks and sanding belts - www.Rockler.com
18 gauge finish nails 1/2", 3/4", 1", 2" for pneumatic air nailer. Used for trim (with glue) and used to hold the 1/8" plywood to the cross struts while the glue dries.
6 - 3/8" x 4" eye bolts
16 - flush mount hinge sets (Blum® Nickel-Plated Face Frame Overlay Hinges from www.Rockler.com) for cabinet doors
10 - drawer slide pairs (75-lb. Quiet-Open 3/4 Extension Drawer Slides - Centerline® 766 from www.Rockler.com) for drawers in the kitchen and camper cabin. Sizes varied depending on the depth of the drawer.
1 qt squeeze bottle & 1 gallon Titebond® III Ultimate Wood Glue - www.Rockler.com
2 - 8 oz bottles of Gorilla Glue
4 - 2"x2"X108" Oak boards - this is a rough estimate -I had rough cut lumber that came in widths between 4" and 12" and lengths between 6' and 12'.
12 - 3/4"x2"x72" Oak boards - this is a rough estimate -I had rough cut lumber that came in widths between 4" and 12" and lengths between 6' and 12'.
4 sheets - 1/2" x 4' x 8' exterior grade plywood (trailer floor, trailer wall that separates the kitchen from the sleeping area, trailer cabin & kitchen structures)
2 sheets 1/2" x 4' x 8' insulation - I used aluminum faced for the face of the trailer
3 sheets 1/2" x 4' x8' insulation - I used plain green (or pink) for the sidewalls.
Trailer exterior Doors - 2 total - 1 left and 1 right side door - http://teardroptrailerparts.com- WD 13 and WD 14
Back hatch hinge - http://teardroptrailerparts.com- HT06
Ceiling Fan - http://teardroptrailerparts.com - Fan04
Fan sealing tape - http://teardroptrailerparts.com - SE05
Back Hatch Latches - 2 each - http://www.zoro.com - Zoro #: G4232575 | Mfr #: PH1283
12 sheets - 1/4" x 4' x 8' plywood with one nice side (interior and exterior walls)
9 sheets - 1/8" x 4 x 8 sanded plywood with the set so the plywood would curve along the 8' axis - this was hard to find. Ended up at a speciality lumber store about 50 miles from my house. Purchased 1 extra sheet just in case I screwed up.
2 sheets - 1/4" x 4' x 8' cherry plywood (for cabinets, cabinet doors, and drawer faces)
20 - 3/4" x 4" x 8' cherry boards (cabinet frames, cabinet doors, trim, shelves) - this is a rough estimate -I had rough cut lumber that came in widths between 4" and 12" and lengths between 6' and 12'.
8 - Cabinet knobs - Rockler.com
5 - Drawer pulls - Rockler.com
12 - 3/4" x 4" x 8' clean pine boards
36 - 8' firing lath - you only need about 6' from each lath but the 6' needs to be straight and knot free. These are are used as the cross struts to connect the two sides together. They are also used as sacrificial boards to hold the 1/8" plywood to the cross struts while the glue is drying
15 - 12" x 12" Black Granite floor tiles (hey - if I'm putting in Cherry cabinets then I need a granite countertop - right??)
3 tubes tile adhesive
1 tube tile grout - black
6 tubes OSI caulk - gray
All the following purchased from Amazon.com:
16' of exterior (waterproof) LED light strips - 12 VDC, soft white, self-adhesive
2 - exterior LED flood lights - 12VDC
2 - interior LED recessed flood lights - very small so they would fit in the ceiling of the cabin.
2 - spools DB Link RW18R500Z Primary Speaker Wire - one spool red, one spool black
1 - Marinco 150BBI Marine On-Board Charger Inlet (15-Amp, 125-Volt, Black)
2 - Leviton N7599-W 15-Amp 125-Volt SmartLock Pro Slim Non-Tamper-Resistant Duplex GFCI Receptacle w/ cover plates
2 - Gold Stars GW21500 Chrome RV Reading Light MR16 Base LED Bulb (12v Satin)
2 - LED Convenience Courtesy Or License Plate Light - 6 Internal Warm White LED - Waterproof, Compact 12VDC For Truck, Auto, RV Lighting
8 - SPST Automotive Round Rocker Switch with Blue LED 12 V
Pico 1755PT 22-16 AWG(Red) Flared Vinyl Insulated Electrical Wiring 0.250" Tab Female Quick Connect Receptacle Terminal 100 Per Package
20pc Premium Brass 18-22 Gauge Male-Female Solderless Crimp Bullet Plug Connectors
1 - Sierra International FS40740 ATO 10 Gang Marine Fuse Block
1 - NOCO Genius G3500 6V/12V 3.5A UltraSafe Smart Battery Charger
3 - 50' spools of 12 gauge wire - white, black, and green - I didn't need that much.
2 Pcs 12 Position Covered Barrier Screw Terminal Block 600V 15A
1 - Camco 25003 Universal Vent Installation Kit with Putty Tape
3 - 12VDC mountable cigarette lighter outlets
2 quarts - General Finishes EF High Performance Polyurethane Top Coat-Satin for the interior and all cabinetry - www. Rocklear.com
3 quarts - Benjamin Moore & Co - Studio Finishes Metallic Glaze(620) - silver
2 - 2" wide x 20' - 3000# nylon freight straps - Harbor Freight
1 roll - 1/4" x 4' x 60' cork underlayment
1 quart - contact cement for the cork flooring
3 boxes - engineered wood flooring - pick your favorite.
30 feet of self-adhesive gasketing material for the back hatch
I'm sure I forgot something.....
Step 4: Building the Foundation Frame
Since I wanted the camper to be removable from the trailer, I knew that I needed some type of skid plates to slide it around on. Using heavy duty casters didn't enter into the equation because I didn't want the camper sliding around on the trailer.
I was somewhat conflicted regarding how to mount the camper to the trailer - seriously considered drilling holes through the floor of the cabin and the bed of the trailer and using bolts or U-bolts to anchor everything together.
In the end I decided not to ruin the integrity of the trailer frame by doing this. Instead, I used two - 3000# 2" wide racketing tie-down straps - the same ones used by trucking companies to tie loads down on their trailers - the drawing shows the frame overlaid on the trailer bed with the trailer tie-down locations and a yellow strip to represent where the tie-down straps fit.
- I started the project by constructing the cross frame (I have no photos of this so the first drawing will have to do). I started with rough cut Oak lumber - 5/4" thick and 10 - 12 feet long. These were cut to 108" long boards, ripped to 2" wide, jointed and planed to 1" thick. I made 8 of these boards and glued & clamped them into 4 pairs using gorilla glue. These were the bottom skid plates for the camper.
- Still using oak, I made 12 - 3/4" x 2" 69-1/2" long slats. Nine of these were placed on top of the skid plates, clamped in place, adjusted the squareness of the assembly, pre-drilled and countersunk. I used a 2" - #10 flat head screw every time a slat crossed the skid plates. Once all the pilot holes were in place, I took the entire assembly apart, coated the mounting points with gorilla glue and screwed the slats down tightly onto the skid plates.
- When this was all dry, I took the 3 reserved oak boards from the last step and cut them into blocks which I inserted between each strut (see the second figure - measure, cut, dry fit, glue, nail) on the exterior skid plates so the floor and walls would have a continuous and solid foundation to be mounted to. Did not block the slots for the nylon strap.
- Make certain the entire foundation is flat and square - I was off by less than 1/16" of an inch off square and it caused headaches during the rest of the construction process.
- The next step was to mount a layer of 1/2" plywood on the foundation frame. I cheated a little here - laid the plywood on the garage floor and flipped the foundation frame over the plywood and marked the cuts and where the foundation slats crossed the plywood. The frame was then removed, the plywood was placed on some 2"x4" lumber and pilot holes were drilled and the plywood was cut to fit the frame. The frame was then placed in the floor, plywood was flipped over and placed on top of the frame and a countersink was used for each of the screw holes. The plywood was raised, all the slats were coated with gorilla glue, and the plywood was placed back on the frame and screwed in place.
- This frame was left overnight to dry.
- The next day, another layer of 1/2" plywood was glued and air nailed (3/4" brads) on top of the first layer making certain the 2nd layer of plywood covered all the butt joints from the first layer of plywood 90 degrees off - the idea was to have a 1" thick floor of plywood that didn't have any long butt joints that were not covered.
- The floor was then flipped over and a bead of OSI calk was placed wherever the plywood and a slat met.
- The entire floor was then coated twice with external wood sealer used for decks in wet climates (I don't remember the brand) and let dry for a couple of days.
Step 5: Building the Side-Walls
Building the sidewalls was a difficult step. I initially needed to create pattern matched interior and exterior walls (see first drawing) with the exterior walls being extending 1" lower than the interior walls (See image).
- To accomplish this step required me to measure, draw, measure, draw, measure, check, measure, check - I needed to ensure the doors were located so they would't hit the tire fenders, they were high enough so I could have some framing entirely around them, and so the walls aligned up perfectly with the floor frame and the slots where the restraining straps would go.
- Additionally since the size of the camper body (big curved box) was larger than a single sheet of plywood and I didn't want plywood butt seams to overlap on the interior and exterior this meant I needed to overlap the sheets of plywood so the interior had the 8' side of the plywood going vertical and the exterior sides were laid out horizontal. Initially I assumed there would be a lot of wasted plywood with this approach, but ended up using the extra wood later in the project.
- I started building the sides by laying out 12 sheets of 1/4" plywood side by side with a 4'x8' side against the 8'x4' side. I laid the plywood out with the two interior finished faces of the sheets facing each other - I wanted the interior wood grain to be as nice as possible.
- I then sketched out the desired shape of the camper on the plywood, correcting the profile curves several times until I got the final profile I wanted. Although I had already done the stick mock-up on the patio, I wasn't totally pleased with the mock-up curves and wanted some curves that were more difficult to create than I could do with the mock-up.
- Once I got the profile I wanted outlined in pencil, I re-drew it with a Sharpie marker (there were a number of pencil curves in some areas and I didn't want to cut the wrong curve), I then laid a cabin door on the plywood and outlined the cutout profile as well as outlined the cutout profile for the back hatch (didn't cut the hatch out until much later in the project). The doors were difficult so get properly positions and I had to adjust them several times until I got them where I wanted them.
- Once I was happy with the layout - ensuring the doors wouldn't hit the tire wells or anything else when opened, I grabbed several wood clamps and clamped all the plywood sheets together. I then strategically screwed all the sheets together so they wouldn't move while I was cutting them out.
- I slid multiple 2"x4"x8' boards under the walls and began cutting using a saber-saw, staying just outside the marked line (most of the time). Once the outside curves were cut and the scrap wood moved out of the way, I drilled four (4) 1" holes with a spade bit on the 4 corners of the door outline. Make sure there is a support board under each of the 4 points so the spade bit doesn't tear the final layer of plywood when it pokes through that layer. With the 4 holes drilled, I cut the door openings out.
- When I was completely done with cutting the sidewalls I removed the screws I had used to hold the plywood sheets together and began to take the walls apart - labeling the pieces as I took them apart - Interior wall 1,2,3,4,5,6, Exterior wall 1,2,3,4,5,6. I did the labelling on the sides that would not be exposed to the interior or exterior of the cabin.
- The next step was to frame the walls. Many teardrop trailer plans only use 1 or 2 sheets of 3/4" or 1" plywood to provide thickness for the walls - I wanted insulation, structural strength, reduced weight, and the ability to run wiring through the walls of the camper - so I framed it out.
- The framing consisted if 1"x4" pine boards that were glued and screwed or brad nailed to the walls. I framed out the openings for the doors and where the bulkhead between the interior cabin and the kitchen would be as well as where the countertop and interior cabinet would be located. The exterior curves were also framed out with 1"x4" boards - each board was cut with a miter saw to butt together and frame the outer edge of the walls.
- Once the 1"x4" boards have been mounted and dried, use your saber saw to trim any wood that isn't flush with the inner wall.
- Clamp the two interior walls together and sand the edges to make them as close to mirror images as possible - this is the last chance to get two perfect walls.
- The next step was to determine the location for all the lighting, switches, and wiring necessary to be run before installing the insulation and closing the walls up. Since all the wiring in the walls was 12 VDC, that meant running a + wire (Red) and - (Black) wire for each light, light switch, and the fan. I had 2 overhead LED spotlights, ceiling fan, two reading lights (one on each side of the cabin), and LED light strips - in the interior of the cabin and 2 exterior lights - one by each door. The one exterior light and the one LED spotlight were wired to switches next to each door. The ceiling fan had it's own switch so I just needed sufficient wire for a home run (1 red and 1 black wire run continuously to the circuit panel). The reading lights had integrated switches so they required home runs also. Finally I had the LED strip lights - one strip on each side of the cabin running along the ceiling - these were controlled by a switch on the interior cabinet.
- The key thing here is to determine where you want to mount your lights, fans, and switches and run the wires at this stage. Running the wires requires drilling through the 1" x 4" boards pulling pairs or multiple pairs of wires through the holes. It's better to pull an extra 5 feet of wire (and leave it hanging) at this stage and cut it back later than to only pull 3 feet and come up short when it comes time connect everything up.
Step 6: Mounting the Sides and Roof Struts
At this stage we've got a cabin base and two interior walls that are hopefully exact mirror copies of each other.
- The next step is to mount the interior walls to the floor. To do this. I used an extension bit and drilled 1/2" holes about half way through the bottom of the frame (Drawing above - bottom image). I drilled 9 holes on each wall and then used long 3/8" brad point bits to finish drilling through the frame. Next I ran a strip of glue along the bottom of one wall and mounted it along the edge of the base frame using 3" #10 screws to hold the wall in place. Repeat the process for the second wall. I then took some of the firing lath and carefully measured the distances between each wall as mounted on the floor and used the firing lath and screws to temporarily hold the walls as parallel to each other as possible while the glue dried.
- The interior walls are now mounted and you have the wires pulled through the walls. It time to install the insulation - I used 3/4" - 4'x8' sheets of insulation. Measure the space in the wall between the 1" x 4" boards, cut the insulation to size. I usually cut a fraction larger than measured so the insulation would be a tight fit. I had to cut grooves in the insulation where the wire was in the walls.
- Mark where the wires are as you install the insulation - both on the insulation and on the 1"x4" boards. This is very important to do so that you don't drive a screw or nail through your wiring later on. As soon as you get the insulation installed.
- Each wall has been framed with 1x4 lumber, has some wiring for future lighting pulled through it, has been insulated, and has been through a sanding process to ensure the edges of the walls are as similar as possible.
- Next dry fit the exterior walls and marked them to show where the wiring is so you won't nails or screws in those areas. Additionally, the exterior walls were marked to show where the bulkhead between the cabin and the kitchen goes and where the shelf over the head board was to be mounted. The exterior walls mounting holes were marked, then drilled and countersunk. Once an exterior wall piece was ready, glue was liberally applied to the framing and the exterior wall panels were screwed in place.
- The next step was to mount the bulkhead between the galley and the cabin - this consisted of 3 main pieces of 1/2" plywood - two mounted vertically and one horizontally.
- The bottom piece height was set so I could fully slide a cooler beneath it and still leave room for a 2" shelf above the cooler - nominally 28" in my case. Once the bottom piece was cut to size (approximately 69 3/4" x 28") it was dry fit and the location was marked on the floor and interior walls. I used a level to make sure the piece was perpendicular to the cabin floor. Remove the bottom piece and drill mounting holes through the walls from the inside of the cabin, put the bottom piece back in and drill 1/8" pilot holes into the plywood from the exterior. This is followed by running a line of glue around the sides and bottom of the plywood and use 3" #8 flat head screws - countersink the exterior walls before using them. For the bottom I used 1" brad nails and secured the bottom of the plywood bulkhead to the cabin floor.
- The horizontal part of the bulkhead is installed next. Make sure to use a measure at all 4 corners of the plywood to ensure this piece is parallel to the cabin floor.dry fit, mark, remove, drill from the inside, re-install, drill from the outside, countersink in the outside, glue the top edge of the bottom bulkhead and the edges of the horizontal plywood, install it screw it together. This it the foundation for the galley tabletop and the bottom of the interior cabinets. This piece of plywood will get a 3/4" wide piece of cherry trim later, so make sure it is at least 3/4" to 1" shy of the back edge of the galley - there will be a galley door that needs to close!
- The next piece is the final vertical bulkhead. I cut the width of the plywood to 69 3/4"" and then dry fit it on the horizontal bulkhead moving it forward and back until I got it where I wanted it - it needed to be located so there was 2 1/8" to 2 1/4" of clearance - once if positioned it and marked it for cutting to vertical size I cut and re-fit it. Follow the same process as above - use a level to get it vertical on each wall, mark, drill, etc...
- Adding the bulkheads really stabilized the side-walls. Next I added a couple vertical partitions in the galley to make three sections.
- One section to be used for sliding shelves for the propane grill and propane stove, one section for a cutlery drawer, cooler, two -12 VDC batteries, and a plastic container for the pots, pans, misc cooking utensils. The final section was for 2 - 6 gallon containers of water, a drawer with a hole cut in it for a plastic bin to use as a sink, and to store a couple hydraulic jacks to stabilize the trailer at night (last photo).
- Next was the installation of the firing lath struts between the two walls. The firing lath must be straight with no knots. Each one was cut individually - the walls have a tendency to warp a little and by measuring the exterior at each point a strut was to be installed I was able to pull or push the walls in/out by 1/8" to 1/16" of an inch. Each strut was dry fit, predrilled, glue applied, then screwed into place with a single 2 1/2" #8 flat head screw.
- At the top of the cabin this process changed a little - I wanted a 12 VDC powered roof vent to be installed. To do this, I used 1"x4" pine lumber to build a mounting hole for the roof vent. I cut 4 - ~69 3/4" x 1" x 4" pine boards - mounting two flush with the top edge of the trailer walls separated by about 12 1/2" (you will have to adjust for the vent you purchase. I then mounted firing lath struts against the outer edges of the 1" x 4" - glued and nailed with 2" nails. Four 1" x 4" x 12 1/2" boards were cut and dry fit perpendicular to the long boards. I used the Kreg jig to drill 2 holes in each end of the short boards, glued and screwed them to the long boards.
- The thickness of the 1" boards is closer to 3/4" and the firing lath struts are nominally 2" wide, so sandwiching 2 - 1" by 4" boards together still leaves a slight gap on the underside. To compensate for this, I cut some strips of 1/4" plywood and used them in between the 1"x4" to gain the thickness needed.
- NOTE: it's really important to run the ceiling fan wiring from the sidewall to the location where the ceiling fan will be wired at this time. If you forget to do it, it'll be really difficult to hide later on.
- Complete the installation of the struts - about every 6" - 12". Stop mounting firing lath struts about 12" from where the back hatch is to be installed - the pine firing lath isn't strong enough (IMO) to handle the mounting of the back hatch hing - I was worried about the mounting screws stripping out so I made 2 pair of 3/4" x 2" by ~69 3/4" oak boards and glued them together. Once dry, they were mounted as the final two roof struts - glued and screwed to the sidewalls. I used two 3" - #10 flat head screws here.
- Before completing this stage of the project, I installed 6 - eye bolts along the roof line. The idea was to have mounting points for tarps when stuck camping with heavy rain or to provide for tie down points for a roof rack for a kayak in the future. The eyebolts were 4" to 6" long - I don't remember what the hardware store had in stock at the time I used 3/8" galvanized eyebolts - first I threaded a nut the entire length of the eyebolt, added a washer, and inserted into pre-drilled holes in the wall. Then I installed another washer followed by two more nuts. Before I tightened the nuts down, I pulled the eyebolt out about 1 inch and liberally coated it with OSI caulk and pushed it back in and tightened everything down. The eyebolts came in really handy to a tie tarp to during the trip.
Step 7: Interior Ceiling
- Mounting the interior cabin ceiling was the most difficult part of the entire project. I picked up some Italian made 1/8" plywood ( 4'x8' sheet) that was made to flex along the length instead of the width of the plywood. I started by carefully measuring the interior of the cabin width between each wall. The walls were pretty parallel but there was variance (within 1/8") side to side along the top of the ridge line. The interior width was a nominal 69 1/2" and required nearly 11 feet of plywood - three sheets side by side. The 1/8" plywood is very thin and trim nails just punch right through it - so I needed a way to hold the plywood against the frame struts. Before beginning the installation, I cut about 30 pieces of 1/4" - 1" x 12" pieces of plywood and used them as nailing blocks to hold the plywood against struts while the glue was drying.
- The first piece installation was easy - it went from the front cabin floor up 4 feet. The curves for this piece were pretty simple and it was easy to install. I cut the piece, dry fitted it and verified it fit properly - had to add in two extra struts for the bottom and top of the plywood to be attached to. I fired up the air compressor and loaded the finish nailer with 1" nails, spread glue on all the struts, pushed the plywood against the struts and used the nailing blocks to hold the plywood tight against the struts until the glue dried.
- The second piece was the problem child for the installation - this was a very tight inside curve, it was overhead, and keeping it in place was difficult. Following the pattern from the last piece, measure and dry fit - everything seemed to be ok... the problems started when we tried to hold it in place and nail it against the struts. I had both kids inside the cabin with me, holding the wood in place as I glued and nailed it tight. The inside curve was too tight and I cracked the plywood about 6 inches up from the seam, after I'd nailed a lot of the plywood into place. Fortunately I still had access to the exterior and was able to layer a couple layers of the 1/8" plywood on the backside and glue/nail everything together to fix the crack.
- The 3rd piece went in pretty easily and I was almost done with the interior ceiling. The final step was to carefully cut out the hole for the vent. To do this, I used a Dremel tool with a fine saw blade and cut from the exterior. This actually worked pretty well.
- During this stage I also made a shelf - 3/4" x 10" x 70" that was mounted in the front of the cabin. This was placed so it would be convenient to reach up to while laying in bed and put water bottles, reading glasses, books, etc. up for the night. The shelf was trimmed to 69 3/4" to fit in the cabin.
- The location for the shelf was noted on the exterior cabin walls when they were glued and screwed on, so it was easy to mark, drill, and countersink the holes through the outer wall (See the drawing for a reference regarding the shelf location).
- The shelf was held in place while the apprentice used an ice pick to mark where the pilot holes in the shelf were to be drilled.
- Once the shelf pilot holes were drilled we used 3" #10 screws to mount the shelf - I didn't use glue here because the fit was tight and I didn't want to get any glue on the cabin walls. The mounted shelf can be seen in the first photo above.
- The final step was to paint the interior ceiling flat white, starting at the shelf at the front of the cabin to the back of the cabin - I taped and covered all the shelving and the walls to prevent drips from ruining any of the interior finish.
Step 8: Insulation & Exterior Bulkhead
- The next stage was to insulate the exterior bulkhead. I used nearly 3 - 4' x 8' sheets of 3/4" foam insulation and a couple cans of spray foam insulation to hold everything in place. Once the spray foam dried, I used a fine hand saw to cut the foam flush where it had expanded higher than the exterior struts.
- Mounting the exterior plywood was much easier than the interior - spread some glue on each strut, bend the plywood around the curves, use a nail gun with 1" brads and strips of plywood to hold everything in place until it dried.
- The one problem was the seam between the sheets of the plywood - as can be seen in the second and third photos. Sealing the seams was really difficult - body putty and marine grade epoxy and finally a 1" strip of plastic with OSI caulk along the entire seam - the finished result is shown in the last photo.
Step 9: Wiring
The wiring for the camper was not as complex as I had originally anticipated - it was just tedious to pull all the 12VDC wires and make sure they were properly in place before I finished working on something that would prevent me from getting access to the wiring in the future.
- The camper was to be self-contained using two 12 VDC light truck batteries for all electrical needs (photos 15, 16). I had considered deep cycle marine batteries - but the weight and expense just didn't justify the purchase for the amount of expected use.
- I also considered installing an inverter (I have a 1200W unit from another project) but decided that it really wasn't going to be necessary and that running 120VAC devices via the inverter wasn't an avenue I really wanted to go down.
- I created a wiring closet in the interior of the the cabin between the two storage cabinets and a removable drawer (see photo #1). Photo #2 shows the cover to the "wiring closet" with the drawer removed.
- I located it under the big center drawer so I could remove the drawer and have sufficient work space where the wiring was contained.
- Starting with the AC power: I added the ability to connect to campground 120VAC power - if it was available then we would use it.
- The 120VAC was wired to two GFCI outlets and to a battery charger - with the battery charger connected to an outlet that was in series with one of the GFCI outlets. The GFCI outlets are being used as the circuit breakers for the camper, in addition to the circuit breakers that are provided by the campgrounds as part of the AC outlets at the sites.
- I used 12 gauge multi-strand wire for all AC connections.
- Wiring was pretty simple - see photos 6,7,8,9,10.
- 120VAC comes into the cabin through a weatherproof side side port (three photos of the apprentice engineer above).
- The Ground (Green) goes directly to a wiring block that is common for all the 120VAC outlets.
- The initial run (neutral - white, and hot - black) runs to a 120VAC GFCI outlet in the interior cabin.
- This GFCI outlet then runs to a standard 120VAC outlet for the battery charger
- The standard 120VAC outlet is then connected to the galley 120VAC GFCI outlet. Photo 9 (I know the second GFCI isn't necessary).
- The battery charger is connected to the interior outlet and feeds the batteries located in the galley area on the other side if the cabin bulkhead.
- The entire 12 VDC circuitry was physically separate from the 120 VAC with every 12 VDC circuit being fused separately - I used 18 gauge wire for this. See photos 6,7,8,9,10.
The concept of operation for using two batteries is as follows:
· Battery 1 is connected to the battery charger and when AC power is available the battery is being charged.
· All lights and the ceiling fan are powered by Battery 2 during this time.
· When the charge of Battery 2 starts dropping (very noticeable when the fan slows down), we swap the connections on the batteries and Battery 2 is charged while Battery 1 provides the 12VDC source.
· When no AC power is available, I could swap a partially drained battery with the main truck battery and charge it during the day while we were driving around and swap it back out that evening - that way both batteries are used, but at no time is either battery completely drained.
· We were able to get nearly 8 days of use out of the combined battery setup without needing to recharge a battery - this included lighting for 3-4 hours every evening and running the ceiling fan for at least 8 hours a night.
- The following circuits were run:
- Exterior Door Lights
- Interior reading lights
- Ceiling fan / vent
- Interior flood lights
- Interior LED strip lights
- Galley Hatch LED strip light
- Galley Hatch LED flood lights
- Interior 12VDC socket
- Exterior 12VDC socket
Photos 12, 13, 14 show hidden wiring using trim, interior cabin light switches mounted by the door - one switch goes to the interior roof flood light and the second to the exterior door light and the exterior door light.
The final photo is everything all wired up and closed up.
Step 10: Installing the Roof Vent
The roof vent was dry fit during the installation of the roof slats.
- All that is left is wiring and water proof installation for the roof vent. The wiring was a little difficult - you are bent over and reaching over your head to solder the fan wires to the wires you pulled earlier when you were building the walls and installing the roof slats
- Once the soldering is complete, I used a couple wire nuts and some electrical tape to insulate the connection.
- When the wiring is complete (and tested) then carefully outline the roof vent on the exterior roof with a marker.
- Partially remove the roof vent and use the the putty tape to lay a strip down within the markings of the vent outline.
- I overlapped the edges by about 1/8" on each corner so that when the ovent was tightened down the putty would squeeze out and make a good seal around the vent.
- Re-place the partially removed the roof vent and install the mounting screws - I tightened all the screws down until they just touched the plastic rim of the vent.
- Once all the screws were installed, I then tightened each screw 1 turn at a time, working my way around the vent multiple times until the putty tape was slowly squeezing out and the vent was securely mounted.
- After completing the installation of the vent to the external part of the cabin, the internal panel can be installed to cover the seams around the interior roof and the vent.
- Interior trim was installed after this installation was complete to cover the seams between the sheets of plywood.
Step 11: Cabinetry - Part 1
I've broken the cabinetry construction into two parts.
- The first part is the creation of the cabinets (galley and interior), installation of the galley countertop, and galley trim installation.
- The second part is the fabrication of the cabinet doors for the galley and the interior cabin as well as the construction of the drawers.
Starting with the galley cabinets, countertop, and trim. All the cabinetry and trim started as rough cut 4/4 or 5/4 cherry lumber that was ripped, jointed, and planed to 3/4" thickness, 1 1/4" width, and cut to length.
- The first photo shows the almost finished product with the doors, countertop, and trim installed.
- Cabinets were started by creating the face frames first - these had to align at the top with the oak strut that was installed to support the back hatch. The top and bottom of the face frame were cut to 69 3/4" long and 10 stiles were cut to 24" long.
- Kreg pocket screws were used to connect the horizontal and vertical face frames.
- The face frame was then connected to the cabin walls and the galley countertop - measure, measure, and measure for this installation. The face needs to be perfectly flat for the doors to fit properly and parallel to the cabin bulkhead behind it.
- Once the face frame was installed two pieces of 1/2" plywood were cut to fit behind the two center stiles (see photo 3). Once the plywood was dry fit - 4 pieces of 1/4" cherry plywood were cut to cover the 1/2" plywood. The cherry plywood was glued and clamped and let dry.
- Using photo 3 as a reference, there are 3 separate cabinet areas. The center cabinet area will be split into two in a later step. For now, the cherry plywood made in the prior step was installed so each piece was flush to the center cabinet area.
- The back of each cabinet area was measured and a piece of cherry plywood was glued and nailed with 1/2" brads to it.
- The bottom of the side cabinets were also covered with cherry plywood cut to size.
- Next two shelves were cut from 1/2" plywood - one for each of the side cabinets. Strips of cherry (1/4" thick) were glued and nailed in the cabinets so their tops would support the plywood shelves. The 1/2" plywood shelves received a covering of 1/4" cherry plywood also.
- With the shelves in place, two more stiles were installed using pocket hole joinery to split the cabinets to support the cabinet doors (photo 5).
- The shelves were then covered with cherry trim (photo 5).
- The cabinets and sides of the galley were then sanded, sealed, sanded with 220 grit, and resealed. I did this to make it easier to clean up any squeeze out from installing the tile adhesive or the tile grout.
- With the cabinet frame complete it's time to install the galley countertop. I needed 10 pieces of 12" x 12" black granite tiles but purchase a couple extra pieces in case I screwed up during the cutting or installation process.
- Start by laying out the full sheets of tiles side by side at the front edge of the galley countertop. Once they are laid out, center them so there is an equal distance on each side of the tiles to the cabin wall.
- Mark the location of the tiles as centered and then measure for the left and right side cuts. A single tile should yield both sides - remember when cutting tiles you want to keep the good edge against the other tiles and the edge you cut goes against the cabin walls or the cabinet frame. Measure this cut a couple of times to get it right before doing any cutting.
- Once the front row of tiles is in place start measuring the back row tiles and cut them to fit. The final cuts will be the left and right corner cuts and they will use a full tile between them.
- Once everything has been dry fit and fits correctly, remove the tiles.
- I purchased a couple caulk tubes of tile adhesive rather than getting small bucket of adhesive. I squirted the adhesive on the galley top and spread the adhesive using a really cheap plastic tile trowel that I could dispose of when done.
- The tiles were then placed back into their positions starting at a back corner, working across the back, then adding the front row. All the tiles were tapped into place using a piece of wood that had been wrapped with old carpeting to make it 3 or 4 inches thick.
- Once the adhesive was dry I installed the front cherry trim (this piece was sanded and sealed before installation).
- For grout, I purchased a single tube of grout tinted black and applied it according to the manufacturer's instructions. I only used about a quarter of the tube.
- Cleanup was pretty easy since I had already sealed all the wood surrounding the tiles - I just carefully sponged anything that got on the wood off. If I hadn't sealed the wood earlier it would have left an ugly black stain. I did take the precaution of using blue painters tape on all exposed wood but when I peeled the tape off there were a couple places it has seeped under the tape.
- The center cabinet was split horizontally into a space to store paper towels and a wine rack to hold 3 bottles of wine. Don't travel with wine bottles in the wine rack - the necks will break! I didn't try it but it's pretty obvious they will. The wine rack is visible in the first photo in the Lessons Learned section.
- A small piece of the cherry plywood was cut to fit in the center cabinet that was tall enough to mount the 120VAC outlet, a couple 12VDC outlets, and some light switches. Once I had the plywood properly sized in length and the electrical hardware was installed and wired I mounted a couple pieces of scrap wood to the sides of the cabinet to attache the plywood to.
- Next a 3/4" x 2" x 10" piece of cherry was cut and two pocket holes were drilled on each end of the wood and attached it above the outlet box.
- I installed a series of shelf supports (1/4" strips of wood) and cut a piece of cherry plywood to form a top to the small box where the electrical components were installed.
Now on to the interior cabin cabinet frames and the drawer
- The interior cabin face frames were made with the same materials the galley frames were made of. They are the same height and don't have a center stile for the doors to close on though, which makes these cabinets appear larger. Also, they don't have shelves in them - the intention for these cabinets was for clothing, towels, linens, etc.
- The cabinet started off with just the bottom shelf that was installed when the sidewalls were installed and also serves as the galley countertop on the other side of the bulkhead.
- I cut two pieces of 1/2" plywood - 24" wide by 30" long and installed them to separate the bottom shelf into 3 sections - 2 - 24" and one 20" center section.
- I marked on the bottom shelf and the bulkhead where these were going to be installed - thin pencil line on both sides of the plywood dividers.
- The dividers were removed and three holes were drilled on the bottom shelf and two on the bulkhead where the centers of the dividers were to be installed. The holes were countersunk in the opposite sides.
- The plywood dividers were coated with glue and I held them in place while the apprentice drilled pilot holes and then installed 1 1/2" #6 screws to permanently mount the dividers.
- The next step was the installation of a series of 1/4" wide wood strips to provide support for the plywood top of the cabinet. These supports can be seen in photo 8.
- The cabinet top was then cut from 1/2" plywood - this was cut to fit. It was initially cut to 69 1/2" wide and 24" deep, but the cabin dimensions were not perfect so I had to trim a little in width to get it to fit. Also note the hole with wires coming through it in photo 8.
- The cabinet top was glued and nailed to the supports and the two center dividers (1" brads were used).
- The top and bottom cherry frames were cut and the remaining 4 cherry stiles were cut from the same stock as the galley cabinets. Pocket holes and glue were used to create the frame. I did have to use a small hand plane to shave the frame down a fraction of an inch in width. I took some wood off both sides with the upper right hand corner being the most difficult to fit - the interior wall had a slight wave in it at that point.
- Unlike the galley, these cabinets are deep enough I could use the Kreg Jig to drill pocket holes in the plywood and attach the face frame with screws and glue.
- With the cabinet front in place, I framed in the space above the cabinet (photo 10) - it was about 12" at the front and 6" at the rear where it intersects with the bulkhead. This space was left open to hold pillows, sleeping bags, and other stuff and the framing was installed to help hold the light weight stuff in place.
- Also notice in photo 10 - at the back of the photo there is a cable run made out of 1/4" x 3/4" cherry that is used to cover the wires that were run through the cabin walls and drop down to the "wiring closet" discussed in the section on wiring. This cable run was cut to fit and glued in place once the electrical wiring is in place.
The final two photos in this section are photos with the Kreg pocket hole jig and how it was used to create the face frames.
Step 12: Cabinetry - Part 2
In this section we will cover the creation of the cabinet doors, installation of the doors, and creation of the drawer for the interior cabin.
- Like the face frames in the prior step, I started with 4/4 cherry boards - ripped, jointed, and planed to the rough dimensions needed for the cabinet doors - 3/4" thick, 2" wide, and various lengths.
- These boards were then sorted through and 18 stiles (upright portion of the doors) were made. They were cut about 1 inch longer than the finished doors were planned to be to enable trimming during door construction.
- The rails were left as longer boards at this stage so I wouldn't be running a 6" long board across a table saw dado head or across a router bit.
- All the cherry boards were routed with a quarter round bit to take both edges off the front of the boards.
- The boards were then carefully inspected and the inner and outer door edges were determined for each board and the inner edge was marked for the dado cut.
- The dado head on the table saw was set to remove 3/8" of material in depth and 1/2" in width on each board.
- All the boards were sanded on a belt sander at this stage.
- The next step was to cut the rails and stiles to size with the miter saw. I made 4 interior doors.
- Once the miters were cut, I laid out each future cabinet door (face down in pieces) and marked left/right and cabinet position (door 1,2,3,4) and then measured, marked, and drilled the holes for the hinges.
- The rails and stiles for each door were then assembled - glue on the common miter edge and 1 1/2" brad nails to hold the door in place while the glue dried. I did the assembly on a piece of granite left over from another project so I would have a nice flat table.
- While the doors were drying 1/4" cherry plywood was cut to fit in each door. When the door was dry, a thin line of glue was applied to the dado cuts in each door frame and the plywood was pressed in and something heavy was placed on the plywood to hold it in place while drying.
- Hinges were installed on all the doors and they were dry fit to the cabinet frames.
- Once the dry fit was complete they were removed, the hinges removed, door knob holes were drilled, and each door was given a final hand sanding.
- After hand sanding the doors, they were sealed, let dry, lightly sanded, and sealed again.
- Hinges and door knobs were installed and the doors were installed on the cabinet frames.
The interior of the cabin has a big drawer that is basically a box on drawer slides. I used 75# drawer slides rather than the more inexpensive slides that are typical in home use - I wanted strength and stability and something that wouldn't fail as it was being shaken going over a washboard road.
- The drawer started with 2 - 1/2" x 12" x 24" and 2 - 1/2" x 12" x 18" pieces of plywood.
- The table saw was set up with a 3/8" dado blade and each piece of plywood received a 1/4" deep dado cut 1/2" in from the edge of the wood.
- Measured a piece of 1/4" plywood (leftover from the cabin wall) to fit the bottom of the drawer.
- I really cheated on the drawer - I glued the front and back pieces to the side pieces (don't forget to put the drawer bottom) and used brad nails to hold it together.
- Next I mounted the drawer slides on the drawer and the cabinet and inserted the drawer into the cabinet mounted slides. There was some friction which resulted in creating a 1/16" shim that I mounted on the back right cabinet slide to fix it.
- Finally, I cut a piece of the 1/4" cherry plywood and glued that onto the draw to provide a nice drawer face and sealed the drawer face.
Cabinetry stage is now complete.
Step 13: Installing the Drawers in the Galley
The first photo above is my favorite shot of the galley in use - Father's day at the Grand Canyon and my kids are fixing me breakfast in bed - I was served bacon, eggs, hash browns. There are 4 drawers in the galley - three of the are just pull out shelves while the 4th is for kitchen utensils and has an odd shape.
The pull out shelves are real simple to make - I took 3/4" x 1 1/2" x 18" oak boards and mounted them to drawer slides. The drawer slides were then mounted to the cabin wall and the dividers under the galley countertop.
Three pieces of 1/2" plywood were cut to size and screwed onto the oak supports.
The two shelves on the left had eye bolts added to their surface and rubber tie-downs are used to hold the stove and grill in place when they are not in use.
The right hand shelf had a hole cut in it that fits a rubbermaid storage box the I've used for years as a wash basin during camping trips.
Step 14: Building the Back Hatch
The back hatch was the most complex part of the entire construction process. Because of the size it needed to be rigid during transportation and to be able to support it's own weight when open - I didn't want one side to sag if it wasn't supported while it was open because of the stress it would put on the hinge.
- The hinge was a special order hinge that was designed to prevent leakage and I was really concerned about damaging it.
- To start the back hatch, I used a pair of dividers and traced a 2" line along the back of the cabin from the point where the oak hinge struts were to the floor of the cabin.
- Once I had the 2" line on both sides of the cabin, I used the trusty saber saw to carefully cut the two exterior hatch pieces from the cabin.
- I then used these two shapes as the guides and drew 5 more arcs on a piece of 1/2" plywood.
- I cut about 1/8" outside the guide lines for all the arcs to leave wood for final contouring of the hatch.
- Once all the arcs were cut, I sandwiched the 5 arcs and the two cabin pieces together and clamped them in multiple locations. It took awhile to align all 7 pieces up - they were all cut by hand with a saber saw so there were variations unfortunately.
- The next step was to drill three holes through the assembly and to insert some threaded rod through the holes and to tighten then all together.
- This provided a very solid unmovable assembly that could be taken to a belt sander and the interior and exteriors were sanded to provide a smooth common face on the interior and exterior of the arcs.
- The cabin walls where the hatch pieces were also sanded (carefully) to maintain the consistency of the arcs and to provide sufficient space for the gaskets that would be mounted on the hatch and cabin to prevent water intrusion.
- I made 3 - 3/4" x 2" x 72" oak struts - one for the bottom of the hatch frame, one for the top. I then cut 3/4" from the top and bottom of the curved hatch struts. The remaining strut was cut to fit inside the two exterior struts and glued/screwed to the top oak strut and to the exterior studs (see drawing). Like I mentioned when framing the cabin struts - I used double oak struts for where I was installing the hinges for strength.
- I also cut 3/4" of an inch from the bottom of each of the 5 interior struts and cut 1 1/2" from the top of each strut - I did not cut a full 3/4" and 1 1/2" initially - I made each cut a little shy of the final fit size to give me some leeway incase something didn't fit right - once I dry fit each strut and verified how much additional cut was required I finished the cuts. Note: I cut from the top and the bottom - just hacking off 2 1/4" from one side or the other would have resulted in arcs that no longer matched the cabin wall arcs.
- The 5 interior arcs were then put into the hatch frame and adjusted until they were spaced 12" apart - center to center. This resulted in the wall arcs and the first arcs in from the wall being less than 12" apart.
- With the interior arcs in place, I drilled pilot holes from the bottom struts into the arcs and using 2 1/2" #8 screws on top and 1 1/2" #8 screws on the bottom I mounted the interior arcs.
- Next I cut the arc cross braces. I used firing lath again (all the left over pieces from framing the cabin roof were used here). I don't remember the length I cut the firing lath to - nominally 11 1/2" for the interior locations and less for the struts between the hatch edge and the first arcs in on the left and right. I made 36 of these struts initially then added a few additional in to provide support for the hatch latches and for mounting points for the LED flood lights.
- It very important to square the frame up at this stage and to remain aware of the need to keep the hatch frame square throughout the rest of the framing process.
- Installation of the arc cross braces was done using 1 1/2" brads in the finish nailer. I would coat each end of the cross brace with glue, position it, and drive 2 brads into each end. Notice in the drawing and photos that each brace was offset from the one adjacent to it so I could get the nails in straight. I also put spacers between every arc at the top and bottom of the hatch and nailed/glued these in place.
- Once the frame was dry, I installed the hinge and dry fit the frame to ensure everything was good to go for the remaining construction.
- The next thing to accomplish is the installation of the hatch latches - I purchased marine grade hatch latches from West Marine and cut a couple 3" long pieces of angle iron to attach to the cabin walls. Latch installation was accomplished following the directions that came with the latches and using scrap pieces of the the 1/8" plywood to get the spacing right on the outer shell of the hatch. These needed positioned and framed out so they could be mounted to latch the hatch down securely.
- Before beginning to cover the hatch with plywood I ran the wiring (two circuits) for the LED strip lights and the LED flood lights. One flood light was positioned so it would shine on the stove and one was positioned to shine where the dish sink was to be located. The wires come out the top left corner of the hatch and are terminated with connectors that enable the removal of the hatch.
- The final step for constructing the hatch is installing the plywood coverings. I used the remainder of the 1/8" plywood for both the external and internal sides of the hatch.
- The external side of the hatch was covered first - using a full sheet to cover most the the hatch and some smaller pieces added at the bottom. This was glued and then held in place with brads until dry.
- The interior of the hatch was covered with the remaining pieces of 1/8" plywood - hence the patchwork in the photos above.
- The seams and all the nail heads were all sealed with bondo and sanded down to be flush.
- It was then sealed with marine grade epoxy and coated with white primer - inside and out.
- When the primer was dry, strips of gasket material were applied to both the cabin arc and the hatch to prevent water from migrating into the galley area.
- The hinge was heavily coated with OSI caulk and mounted on the cabin body (it had been dry fit earlier with the hatch) with screws.
- The hatch side of the hing was heavily coated with caulk (again dry fit first) and the hatch was moved into position with aid from the apprentice. The hinge was then screwed tightly down.
- The caulk took about 3 days to dry sufficiently to trim it back with a drywall knife.
- The hatch lights were installed and the wiring was connected and there was light!
- At this stage I realized the hatch bottom gasket kept peeling off so I had to come up with a better solution to keep water out of the galley. The apprentice came up with a great idea... "Dad, why don't you get one of those strips like they have on the garage door". Off we went to Home Depot and purchased a single 8' long garage door flang gasket (see photo). This was cut to size, heavily caulked and screwed into place so when the hatch closes the flang seals the back from water intrusion. It works really well.
- The final step was the creation of a way to hold the hatch open. I chose the simplest method possible - purchased two 1/2" dowels and made a couple blocks of wood 3/4" x 1 1/2" x 2" that were partially drilled through with 3/4" fostner bits and mounted on the interior of the hatch just inside cabin walls.
- I also took two pieces of 1/8" x 1/2" aluminum bar and wrapped them around the dowels to make mounting points on the galley prep top - these were attached to the galley walls.
Step 15: Sealing / Finishing the Interior
- Trim - the interior of the trailer has solid cherry trim - I made the trim in the shop and it consisted of about 80 feet of 1/8" x 3/4" flat trim made by jointing 1 edge of a 6' to 8' long 3/4" cherry board followed by ripping 3/16" from the board, jointing the ripped edge of the board, and repeating the ripping and jointing until I had all the flat trim - I made about 20 feet more than I thought I needed - just in case. The 3/16" trim was then sanded on both sides with a belt sander which brought the thickness down to close to 1/8". This thickness was chosen because the tight curves in the cabin and the desire to hide the edges where the interior plywood and interior walls came together and where the individual pieces of the 1/8" interior ceiling plywood joints came together.
- I also made about 80 feet of 1/2" quarter round cherry trim by ripping 5/8" square trim, running it through a planer on the two ripped sides to get 1/2" square trim that was then routed with a quarter round bit to give me 1/2" quarter round trim.
- Even though all the wiring runs were complete, I still had to finish the installation of the lights, switches, and other electrical tasks but it was time to install the trim.
- I glued and used small finish brad nails to mount the trim. I mounted the 1/2" quarter round on top of the 1/8" flat trim along the edges where the ceiling and the walls met. To get the 1/2" quarter round to mount properly along the curving roof line, I either cut grooves in the back of the quarter round so it would bend or I cut a series of 2" to 3" pieces with the mitre saw and pieced them together along the curve.
- Quarter round was also installed on the top and bottom of the shelf at the front of the cabin, where the shelf met the interior ceiling.
- The entire interior was coated with two coats of polyurethane (see parts list). I lightly hand sanded the first coat with 220 grit sand paper after it had dried.
- After the interior was sealed the cabinet doors were installed. Note: the cabinet doors were mounted for fit checks much earlier in the process and were sealed earlier in the process - the cabinet doors were finished products when they were installed.
- Then I could work in the floor - I worked on the floor as the final step for the interior finish of the cabin because I didn't want to drop tools or scuff the floor while still trying to finish other parts of the construction.
- Finishing the floor consisted of laying 1/4" cork underlayment on the floor and half way up the front wall. I selected cork for it's insulation and sound reduction properties rather than using newer man-made materials. Using the cork as the front wall head board really helps to deaden sound reflected within the cabin and sound coming in from exterior sources.
- You get one chance to lay everything out right, so measure and dry fit the cork and plan the installation process by dry running the installation!!!
- I used a quart of contact cement and a roller to apply it to the cork (let it dry) and the floor and wall were also covered with the same adhesive (let it dry also).
- Once the cork was down, I installed the wood flooring. I followed the manufacturer directions for this. The hards part of laying the wood flooring was the final run was pretty narrow so I had to rip several floor boards which was a really really dusty process.
- After the floor was down, I installed cork for the headboard and installed the final trim around the entire floor covering up the floor edges with 1/2" quarter round held in place with finishing brads.
- Four coat hooks were installed in convenient locations within the cabin.
- Three curtains were made to block light, velcro was sewn on each curtain, and self-adhesive velcro was mounted above the doors and around the roof vent to block light.
Step 16: Finishing the Exterior
So, I'm going to walk you though what I did, then tell you not to do this.... followed by what I'm doing to fix the problem it created.
- The sidewalls are constructed of 1/4" plywood and the exterior ceiling is 1/8" plywood. I glued, screwed, and finish nailed everything together and thought it would be sufficiently rigid that I wouldn't encounter any problems. Areas where there were nail or screw holes, seams between sheets of plywood or the seam between the wall and the ceiling were filled with body putty and sanded flat.
- Once the sanding was done, I applied two coats of marine grade epoxy to seal the entire exterior. I lightly sanded the epoxy with 220 grit sandpaper after each coat.
- I then applied a coat of exterior primer that was designed to adhere to the epoxy, followed by two more coats of paint. I used a silver metallic paint from Benjamin Moore - Molten Metallics(621). The paint is great at hiding all the little imperfections and adds a lot of character. http://www.benjaminmoore.com/en-us/for-your-home/p...
- The problem that I experienced was during the long trip around the USA, we went on a lot of back roads (washboard type) that caused a tremendous amount of shaking and vibration which caused hairline cracking in the various pieces of plywood where they were joined. Once the crack in the paint and epoxy occurred, there was a place for water to get to the plywood.
- Interior grade 1/4" plywood acts like a sponge when it get wet. This didn't happen for over a year but it wasn't a pretty sight once it occurred.
- So now that you know what not to do for your exterior, here is what I've done to fix my problem.
- I removed the offending pieces of plywood and sanded the camper down. The next step was to carefully coat the entire exterior with fiberglass and lay down three coats of fiberglass resin.
- The issue with working with fiberglass is the open/working time of the resin and then dust hazard when sanding.
- Once the fiberglass resin layer was complete, I sanded after each coat, then primed the exterior again and then re-coated it with the same paint I used the last time.
Step 17: Loading It on the Trailer
Loading the cabin on the trailer was easier than I had expected - with one minor catch... Now I measured everything multiple times before starting this project the trailer bed was 72" and the exterior of the cabin was 71 1/2" everything should have gone smoothly!
The trailer I purchased has two uprights at the real of the trailer to connect the rear ramp to while in transit. Each upright has a small piece of aluminum welded on that extends in just enough that something greater than 71 1/2" will not load and with the doors mounted the width of the cabin was 72" - I couldn't load the cabin body with the doors installed.
- We lifted the cabin and loaded it on moving dollys in the garage and slid one of the tie down straps through the front tie down location and then connected the tie down to a pair of come-alongs to slowly pull the cabin onto the bed of the trailer.
- I put a couple pieces of plywood in front of the cabin skid plates to prevent them from getting jammed into the loading ramp.
- Once the cabin was a little more than 1/2 loaded on the trailer (past the center of gravity) it gently tilted down onto the trailer bed and we just pulled it by hand to it's final placement.
- We relocated the front yellow tie down passed it through and around the trailer and used the ratcheting mechanism to lock the front of the trailer into place.
- The next step was to install the rear tie down and ratchet the rear of the cabin into place.
- Installation of the doors and door drip edge took less than 1 hour - the doors and drip edge had been dry fit multiple times and all the screw holes already drilled. Installation consisted of running a thin bead of OSI caulk on the drip edge and on the door seals, pressing them into place and screwing everything tight.
The only remaining steps were to outfit the cabin and galley and to head out for a road trip.
Step 18: Lessons Learned
- Measure the clearances on the trailer, measure them again, and then compare them to your drawing and verify the dimensions and locations of anything that will be protruding from the exterior of the trailer. The trailer I purchased has two upright mounts at the back for the rear lights and to hold the ramp in place if I would use the trailer to haul 4-wheelers or snowmobiles. Unfortunately, the upright mounts make the trailer 1/4" narrower than the camper with the doors installed. I ended up with 2 options to load the camper onto the trailer - lift it 4' into the air and slide the trailer under or remove the doors and slide the camper onto the trailer without the doors and re-install them. I chose the latter - in hindsight, I would have made the camper 1" narrower and not had this problem.
- I did have a concern about the heat from the grill. I've used the propane stove for decades so I knew it wouldn't cause any problems. I tested the stove on the brick patio first to gauge how much heat it produced by placing a piece of newspaper under it. After an hour the top was too hot to touch but the sides and bottom were not and the newspaper under it wasn't singed. I then repeated the same test in the driveway with the grill located on the galley shelf. Again, no problem, although I wouldn't leave it operating unaccompanied or open the stove shelf with it operating.
- If you are not going to cover the exterior of the trailer with aluminum or fiberglass sheeting, prepare for hairline stress cracks in whatever exterior coating you use. The stress cracks will need to be patched from time to time.
- Getting the back hatch to fit properly is an exercise in patience and careful planning. You have a curved frame that needs to be square and fits the curve of the camper. Don't glue anything until you have dry fitted the frame and know that it fits as best as you can make it.
- Installation of the back hatch latches is difficult - they have to be installed before the plywood is installed on the exterior and interior of the hatch. They also have to be adjusted to catch whatever you are using as the latching posts - I used some 2" angle iron that was cut to fit the latching fingers. Do the adjustments while you can get your hands in to adjust them - otherwise you will be stuck making adjustments a fraction of an inch at a time.
- I would add a couple USB outlets to the interior and exterior electrical panels. They would be 12VDC to USB and panel mounted (last photo)
- I would also add a small nook to slide cell phones into while charging in the galley area. Whenever we had AC power the outlets were always in use by the kids to charge their phones which meant I had phones, wires, and transformers littering the galley area while trying to fix a meal. The nook would have enabled me to slide the phones and wires out of the way.
- If you are going to take a trip across the USA - 4 weeks just isn't enough time - better plan for 4 months!
Step 19: Final Thoughts
I've included a number of photos from our trip around the USA as part of this Instructables to show how the final result of this project was used.
These final photos are just to close out the project.
- Photo 1 is from White Sands NP, NM
- Photo 2 is from Yellowstone NP
- The final two are from the Devils Tower in Wyoming - on the 4th of July.
I made lots of mistakes during the construction and there are many things I would change if given a do-over but all in all we are really pleased with our teardrop. I've attempted to be as complete as possible with this Instructables but without an editor, I know I missed steps or wrote sentences that make sense to me but are confusing to anyone else reading. If you are interested in building a teardrop and want insight into anything in this Instructables don't hesitate to shoot me an email.
Thanks for all your interest in my Instructables!
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