Introduction: Mini Teardrop Trailer
I wanted to build a small (18-1/2" x 39-1/2" x 19-1/2" body) , scale Teardrop Trailer to pull behind the small, scale 1955 Cadillac scooter that I made to ride in a New Orleans Mardi Gras parade. I am a member of The Rolling Elvi (about 120 guys who dress like Elvis and ride scooters in Mardi Gras parades) I wanted something to carry my Mardi Gras throws as well as an ice chest. Initially I considered making an Airstream Trailer, however I felt that it may get to be way too heavy if made to a similar scale as my Cadillac. Therefore I opted for the Teardrop as it also maintained a cool retro look.
Step 1: Materials & Tools
1/2" x 1/8" Steel Angle Iron
1/2" Steel Square Tube
1" x 1/8" Steel Flat Bar
5/8" Steel Rod (for Axle)
10" Pneumatic Tires (from Harbor Freight) w/ 5/8" Axle Bore w/ Bearings
20" x 10' Aluminum Flashing
1/4" Oak Plywood
1-1/2" x 3/4" Poplar Board
1-1/2" x 3/4" Oak Board
Fiberglass Resin & Hardener
9" Galvanized Reinforcing Straps (x2)
1-1/2" Galvanized Angle Braces (x6)
1-9/16" Zinc-Plated Safety Pins (x2) - OR Cotter Pins
3/4" Philips Wood Screws
3/4" Copper Coated Nails
1/4"-20 x 1" Winged Screws
100% Silicone Caulk
Exterior Wood Glue
Exterior Grade Urethane
Bicycle Kick Stand
(Parts from Sindrone's Instructable titled "Quick Hitch for bike trailer": https://www.instructables.com/id/Quick-Hitch-for-bike-trailer/z)
Oversize Copier (I went to Kinko's)
Large & Small Square
Table Saw (not necessary, but helpful)
Hand (Pull-Cut) Saw
2" Chip Brushes
Assorted Drill Bits
Medium Grit Sanding Blocks
Step 2: Building the Chassis
Taking the angle iron, frame up and weld a chassis which has an outside dimension of 18" x 36". Use the Flat Bar Stock to add structural integrity and some vertical tabs (see last two photos to see tabs) to attach the teardrop body (I intend the teardrop part of the trailer to be removable so I could also use the chassis as a flatbed trailer if I so desire). Also use the angle iron to make a triangular tongue in order to attach the trailer to a bicycle or scooter - I made the tongue a little extra long so I could weld it under the corners of the chassis frame for added strength, and to help support the deck bed. I welded a 1" eye bolt to the end of the tongue (stuck within the 1/2" steel tube, which extends back to the front edge of the angle iron frame) to aide in attaching the hitch. By the way, I used 1/2" angle iron for the chassis, because I needed it to hold a sheet of 1/4" plywood as the deck bed of the trailer. I didn't want to use a much larger angle iron because I was concerned about weight...after all, the motor of my scooter is rather weak. I positioned the 5/8" steel rod axle to be 22" from the front of the chassis frame (thus, 14" from the rear) as teardrop axles are not typically centered on the chassis. The rod also adds structural integrity to the frame. In the last couple of photos I just put the wheels on to see how it looks. I ended up welding a strip of 1" flat steel stock to the back edge (on edge) to act as a skid plate as the trailer's rear ended up being a little longer than the frame, and I wanted to protect the teardrop body in case I hit a curb, or whatever (photo to be seen in future step).
By the way, this trailer is not designed to ride the "open road" (aka "highway"). I built this to pull behind my bicycle or scooter (which we lovingly refer to as a "skateboard powered by a weed-eater motor" ...I understand this is the cheapest scooter one can buy). I'd be surprised if the scooter and trailer would hit 25mph. If you wanted to build a mini trailer to pull behind a motorcycle I would highly recommend you ramp up the chassis... install a better wheel set, and even install leaf springs. I've seen applications where people get leaf springs from golf carts to install in smaller trailers. I considered doing so, but was talked out of it by a friend. After all, I'm not carrying a very heavy load, and I'm not going to go that fast.
Step 3: Creating Teardrop Shape
I wanted my teardrop to be a little longer than 3' long (notice that the front of the teardrop trailer shape bulges forward of the chassis frame) and about 18" tall. I took some graph paper and blocked out a rectangle 6" long and 3" tall. I then sketched with a pencil, on the graph rectangle, the shape of the trailer that I wanted to end up with. When I was content with the final shape, I took a fine black pen to finalize/smooth the line of the drawing, because the next step is to enlarge the sketch to the final size at 600%. Enlarging the sketch also enlarges mistakes, so that is why you have to make a nice, dark final line in your sketch. When you enlarge the sketch to the final size, you then have to transfer the shape to the 1/4" oak plywood. I took a pencil and rubbed the back side of the paper enlargement with it to act as sort of a "carbon paper" technique (of course if you have carbon paper - use it). I then taped the enlargement to the plywood and, using a ballpoint pen, traced over the line - thus transferring the shape to the plywood. Be conscious of the wood grain patterns on your boards, so that the better patterns will end up on the outside of your trailer.
I firmly clamped two sheets of plywood together to then cut out the final shape with the jig saw - This is more exact than cutting each separately. By the way, a band saw would be helpful here (I don't have one). After the jig saw does it's job, I then took a sanding block (really a 2 x 4 with sandpaper glued to it) with rough sand paper on it to smooth the shape and to ensure that the two boards are as exactly the same as possible.
Step 4: Adding the Deck
Measure and Cut the 1/4" Oak plywood deck to fit as snug as possible within the frame. I had welded the tabs on the INSIDE of the angle iron in order to keep the exterior as clean as possible. Because the tabs are on the inside, you will have to cut clearance notches on the deck board to accommodate the tabs. I then removed the decking, drilled a few holes in the steel chassis to allow bolting of the deck to the chassis. Next I replaced the deck to mark where to drill for the bolts, and then bolted the deck to the chassis. Not permanently yet.
Step 5: Preparing Back Door Hatch
I cut two 1/4" x 4" x 17'' Oak plywood strips to act as the side supports of the back door hatch. I clamped them to the outsides of the two sides in order to assure they are the same shape, and used that sanding block to assure so...sanding all 4 sheets together. I found it extremely helpful to also make pencil marks across the outer edges of all boards to aid in alignment. I probably drew more marks than necessary, but it didn't matter as the outer edges are to be covered anyway. Some of the things to mark for would be positioning of upper hinge, the board to support the hinges, the lower hatch door jamb, cross members for strength, etc.
Step 6: Attaching Sides
Since my welding is not an exact science, I placed a straightedge along the edge of the vertical steel tabs on the chassis to make sure the 3 tabs on each side were in line with each other (after all, I didn't want to attach the sides and have the sides of the teardrop not be straight and smooth). If they weren't, I used a torch to heat a tab to bend it to be in better alignment. When they were as close as could be, it was time to attach the sides of the teardrop. I drilled a 1/4" hole in the center of each tab with which to mount the teardrop top. When the two wooden teardrop sides were finalized, I then positioned the teardrop sides on the outside of the frame to mark where to drill the mounting holes. I ended up using 1" bolts with wing nuts so that I could easily remove the teardrop shape if I so desired. In the second photo, you can see where I marked on the teardrop side panel as to where the hatch is to be positioned.
You should notice that I also cut some circular window holes in the "door" of the teardrop. The holes ended up being 4-5/8" round (why that size? Because that size looked to scale, and it so happened to be the size of a small plastic bucket I had laying around with which to trace) I drilled a hole and used the jig saw to cut the holes out.
Step 7: Adding Strength
In the next photos you can see that I made plywood panels and solid board stringers to span between the two sides. It's helpful if the two sides are close to exactly the same distance apart along the whole length of the chassis. The large panel you can see separates the rear hatch area (where my ice chest will live) from the larger front section. In the first photo you can also see a single rib laying there which I cut & shaped using the same method that I used for the rear hatch sides in step number 5. This rib will add strength and shape to the front curve.
In the second photo you can see that I cut matching angled plywood pieces to glue to the vertical divider & side panels which will act as a positioning tool for installing the angled shelf within the front compartment. I then glued in the shelf panel. The shelf adds a great deal of strength and integrity to the whole unit. By the way, that short round dowel pieces is glued into the center of the shelf for added strength. I know it doesn't really make much sense, but I did it anyway, so there. In these photos you can also see various boards going across for strength. The board directly above the dividing panel is oak and it is to support the hinge for the back hatch. I used screws and glue to mount these supporting boards as these elements will need to take a lot of abuse. The oak hinge board I did position a little down from the edge of the side panels to allow the thickness of the hinge flaps, as they will be covered by the outer panel sheets. You can see this at the top of the third photo.
In the last photo you can see where I added some supporting stringers across the bottom back edge, as well as strong oak supports towards the front top, where the top hatch will be positioned, and where the front curved panel will have to attach (strength is needed here to assure as little warping as possible).
Step 8: Back Hatch
In the first photo you can see how I fashioned a jamb for the hatch to close against. I also left a 1" span for a latch to be installed. The second photo shows how I glued and clamped additional poplar wood board to strengthen the oak span where the hinge is to be installed. The third photo shows how I notched the side hatch supports to fit up against the span for where the hinge is to be mounted. I made sure that the spans extend a little above the sides so that when it comes to gluing the curved skin, or top onto the hatch, that it fits smoothly against the hatch sides to aide in gluing. The fourth photo shows how I also notched the bottom of the hatch sides to extend into the jamb area as well. The fifth photo shows how I glued an oak board between the two hatch sides, making sure to allow a little clearance on either side to prevent any potential binding. I glued a spruce board at the bottom of the hatch - at the jamb. In the last photo you can see the spacers stuck in the corners between the sides and the hatch unit. You can also see the hinge screwed in place as well. The seventh photo shows the parts that I purchased to use as locking mechanisms for both hatches. These are T-Nuts and a 1" Winged Screw (both are 1/4"-20), and they are found in the small bags and drawers in the nails/screws aisle of Lowe's & Home Depot. When the hatches are complete (without the aluminum), I drilled the proper sized hole for the insert, then pushed one T-Nut into the outside of the hatch and another on the inside back side of the trailer's jamb board. The Winged Screw acts as a locking key. Of course, it is best to determine exactly where you want the locking mechanism, and drill through the hatch & jamb at the same time to help assure everything lines up. The next two photos show how I added vertical members to the top and bottom of the rear hatch to give additional strength.
It was around this time that I felt it would be helpful to have the front end supported better to make the rest of the construction easier. I went to Pep Boys (you can find kick stands just about anywhere there is a bicycle accessories department) and found a kickstand that I could cut to length after determining what "level" would be for the trailer when it is lowered.
Step 9: Preparing the Front
This photo shows the additional rib that I cut and positioned in place. It is important to mount it securely at the top and bottom of the teardrop. The pencil marks that I had drawn in step 5 were extremely helpful at this point to make sure that the curve was exact along all three curved edges. I had also placed a square spruce board across the center front edge of the teardrop which I had to notch out of the rib in order to place/glue it. You can also see 4 square blocks that I glued in the upper corners for additional strength.
The second photo shows both the gluing and clamping of the top of the back hatch board, as well as a good top view of the front of the teardrop with the center rib in place, along with the cross members in front and at the bottom of the front section.
Step 10: Applying the Curved Top
I used 1/4" oak plywood to skin the curved top of my teardrop. I chose oak for it's strength. I know there are other materials out there, but this is what I chose to use. I had some Luan, however I don't trust the layers to be strong enough, and I feared delamination of the layers. In order to make the plywood more pliable over the curves of the teardrop, I had to adapt it to facilitate it's pliability. I chose the kerf method: using a circular saw (I don't have table saw) to cut 3/4 of the way through the sheet in rows 1/2" apart, so there is only one or two layers necessary to bend. After spending a great amount of time marking and cutting with my saw and a straight edge, I found that I had not cut far enough through the board and had to cut further with my hand pull-cut saw. A couple of times I cut all the way through the board, but It was not too great a problem as I was to cover it with aluminum anyway. If I would have placed the rows 1/4" apart instead of 1/2" it may have made it more pliable and smoother of a bend, but I was impatient and felt that if I had difficulty, I could always go back to cut more rows between the existing cuts.
The first photo shows using the hand saw after the circular saw. I found that the front teeth were best for working through the fibers. Notice that I left the leading edge of the board without a row or two so that I could more securely screw it to the lower stringer going across the front of the teardrop body.
At this point I brushed some wood glue onto the bottom of the frame and screwed the bottom to the lower front stringer. I then carefully brushed glue along the edges of the sides and the center rib, as well as the upper stringer, bent the kerf-cut sheet around the curves, clamped & screwed the top in a couple of place to secure it in place. While it was in place I could reach inside to brush some glue within the corners to further secure it.
Please note in the second photo how the board is put on oversized so that it can be cut down later. This allows for a margin of error. I must admit that on one side the kerfed board did not come in contact with one side panel in an area about 4" in length (see fourth photo). I used the jig saw to cut a plywood plug to fill that gap. It looks fine now.
I used the same method to apply the curved top to the back hatch as shown in the sixth photo. I was careful to ONLY put glue on the hatch sides and it's top and bottom stringers. You can also see how I began framing out the top hatch to prepare for it's door.
Step 11: Installing Top Hatch
After determining which side will be hinged, I placed an oak board on the hinge side, with the ends of the board just below the top edge of the side panel. Note that the side curves higher in the center - this will be addressed next. I use oak to secure the hinge to assure strength in holding the hinge's screws.
I made the side arms of the hatch in the same manner that I made the back hatch. Remember to place the arms a little higher than the surrounding wood so that the hatch cover is able to make contact with it when gluing it in place. The main difference between the top hatch and the back hatch, is that the hatch's ends have to be curved to match the curve of the top edge of the sides. The fourth and fifth photos show how I had to curve the top of the hatch's end to accommodate that curve. On the hinge end I also placed a curved piece to match the side's curve. It may look awkward, but it is necessary to maintain the continual curve of the trailer's profile.
The sixth photo shows a rib i put between stringers to help maintain the stringer's positioning, and to give the top panel something else to glue to for strength.
Step 12: Gluing Tops
Here are photos with ratchet straps holding the top panels in place. There may be places to insert a wedge or pillow to add some pressure to uneven areas (or in my situation, a drill's box). Be careful not to crank them too much. Please note that I also had placed kerfed panels in places not previously mentioned, like between the hatches (see where the little rib was placed in last step) and at the bottom of the rear of the teardrop.
Step 13: Fenders
I went the easy way with the fender manufacturing... I took some 1/2" plywood, cut two pieces at 12" x 4", and rounded two outer ends on each. I then kerf-cut each at 4" and 8" location to "bend" it in a rough arch. I screwed a 9" galvanized strap to underside through three 1-1/2" galvanized angle braces as shown in the second photo. Remember that the braces have to line up with the edge of the fender so that the fender sits next to the trailer side. I then used wood filler to fill the kerf gaps in the fenders, and sanded them smooth. After the filler was dry, I brushed on fiberglass resin covering the entire fender - top and bottom. I then painted them red.
I cut some 1/4" oak plywood panels to glue to the inside of the trailer body where the fenders will mount in order to assure a stronger mount. I used machine bolts with lock washers, nuts and Loctite to mount the fenders.
Step 14: Adding Aluminum Skin
First thing to do is to use the jig saw to cut the top, curved panels to be in line with the sides of the trailer. Sand them smooth. Lightly sand the surfaces to make sure they are all smooth. Dust the entire trailer.
In planning the installation of the aluminum I had thought to use industrial adhesive. I admit that I bought and tried two different ones which I was not happy with. I ended up using 100% silicone caulk and also putting little copper-covered nails to help secure the aluminum edges (...they look like little rivets, which is a nice touch)
I put the aluminum on in panel steps. I first covered the front curved section by brushing on the adhesive (silicone) and nailing the bottom edge. Then, using a linoleum roller (used in applying linoleum counter top veneers), I rolled out the rest of that panel. Sometimes, lIke the kerf-cut plywood panels, I used a piece of aluminum which is larger than the area to cover. When the aluminum is secured fully, I am able to use a carpet knife to carefully cut most of the way through the thin aluminum, and then bending the extra aluminum back and forth to break the aluminum off. There were some panels where I cut the aluminum to fit beforehand. For the two hatches I cut the aluminum to fit as I overlapped the edge where the hinge was so that it can be "chased" down to cover the small void.
The first photo is the trailer with the aluminum installed everywhere except the bottom back panel. The second photo shows the aluminum overlapping the edge and chased over to cover the gap.
Step 15: Preparing the Wheels
I ordered 4 steel spacers to slide onto the axles - 2 at 1/2" to put between the chassis and the wheels, and 2 at 1-1/2" to place between the wheels and the hole for the retaining pin. I cut the axle to be about 1/2" past the outer spacer. I was concerned about drilling such a deep small hole. I drilled the hole slowly with oil on the bit, stopping every so often to wipe off the extra metal and to let the bit cool. Even if I had nothing to worry about, I was concerned that the bit may break off in the hole if I was too aggressive.
I used that industrial pin instead of a cotter pin because I wanted to be able to remove the wheels in order to transport the trailer in the back of my small SUV, and it's best if the trailer doesn't roll around back there. I also may need to put the trailer on TOP of my SUV some day. If these needs don't apply to you, a cotter pin may be a better alternative for keeping the wheels and spacers in place.
Step 16: Finishing Steps And... on the Road
I used a wood stain to apply to the outside of both side panels. I then used a black sharpie to delineate a door on each side. To make the doors stand out even better, I applied another stain coat to the doors only. I took the teardrop off the chassis and turned it over so that I could apply extra glue to the intersections of wood members. A day or two later I applied an exterior urethane sealant to all wood surfaces - Inside and Out to help preserve the trailer from inclement weather.
One of the last things I did was to take the plexiglass panels and adhere them to the inside of the trailer's round windows using the clear silicone adhesive. You have to be careful not to get the silicone on the area of the window one looks through. It can get messy if you're not careful. I used masking tape to hinge the plexiglass at the top, and then pushing the plexiglass into the silicone that was pre-spread on the inside areas around the windows. I like to dry fit an item I am to be gluing, and drawing it's outline with a pencil. This way I know exactly where to put the glue and/or silicone. When the plexiglass silicone is dry you can apply more silicone around the window's perimeter from the outside to assure weatherproofing from rain, etc.
I have to admit that the trailer is not fully weatherproof as the hinge areas will certainly leak of there were a full on rain. I am not so sure how to weatherproof them, and welcome suggestions.
I just added a photo of the ice chest that I cut up and reconfigured to fit within the arched rear compartment. I also had to resize the lid to fit the ice chest's new opening. I used a small sheet of plywood to help strengthen the lid, and it also allowed me to make a new handle for the lid -- it was needed as I cut out the original finger-holds from the lid. I used the clear silicone to hold it all together. It works like a charm. I did line the trailer's bottom with soft foam panels to soften the ride for the ice chest. I have a sheet in the front compartment to soften the ride for any items up there as well.
If anyone wants any other photos of any part of the trailer, message me. The last photos are of me in my Rolling Elvi outfit, sitting on my Cadillac which is pulling my teardrop trailer...ready for the parade. The last photo is my rig at one of our pre-parade bar stops. You can see how I applied our Krewe's logo to the back of my teardrop.
By the way, y'all may want to check back periodically as I may decide to add some embellishments to the trailer as time goes on. Not too much... perhaps tail lights, chrome (nicely suggested by Valkgurl - thankyouverymuch). Also, probably a MUST: A proper trailer should have a safety chain in case the hitch fails. That will definitely be an addition in the near future.
Another nice thing about this build is that the teardrop body is held onto the chassis by only 6 bolts & butterfly nuts. In less that 2 minutes I can remove the teardrop and have a flatbed trailer. I'm thinking of constructing other tops for this trailer chassis... awesome.