For Christmas last year I built my very first musical instrument for my son-in-law, Joe. In the process I accidentally wound up creating a whole new class of musical instrument - I was aiming for something called a Pixie Lute or a Stick Dulcimer, but wound up with something we're calling a Chrome Dulcimer. I'm planning to do an Instructable on that when I get the time to put it together. But I also wanted to make a travel case for it - something that would protect it as he goes from place to place performing. Since the instrument has unusual dimensions - 36 inches long by only 5 inches wide and less than 2 inches deep - there really isn't anything out there that would fit it well. Besides, since the instrument is unique I thought it would be appropriate to have a unique travel case for it. I also wanted it to reflect who Joe is - and he's a very down-home guy - so I thought simple materials like pine and burlap would give it a rustic look that would be right up his alley.
As I began designing the box I realized that by simply plugging in a different length, width and depth for a different instrument I could make a box for essentially any size instrument using the same design...and so can you! So I put together this Instructable to show you how to do it. Since the design is scalable I don't dwell too much on the dimensions of this case in my Instructable, but rather on the design decisions that went into making it a sturdy, good-looking and versatile case. Also, since a major portion of the outside of the case is covered in burlap and I assumed that it may not take significant use without showing wear, I designed the case so that all panels can be easily removed, re-covered and replaced to keep the case looking good.
So the positive attributes of this design are:
1. Scalable - The beauty of this design is that you can easily adapt it to build any size box you want. The only thing you need to do is to measure the length, width and depth of the object you want to carry in the box. These measurements will determine the lengths of the frame pieces and the dimensions of your panels - and I've done the math for you so that all you have to do is plug in your own instrument dimensions and you'll have every measurement you need. Every other measurement in the build will be exactly the same as it is in the Instructable - the width and height of every frame piece, the size and placement of every routed notch and channel - all exactly the same.
2. Versatile - I used burlap for the inserts. You can use whatever material you like - fabric, vinyl, leather - or simply use plywood or veneer for an all-wood box. The box can also be used for anything you want to protect as you travel...except maybe the kids.
3. Repairable - Suppose the fabric or finish on a panel insert gets torn or damaged. By removing a maximum of four screws you can remove any given panel, refinish or re-cover it, and slip it back into place, completely eliminating the damage.
4. Easy Construction - All joints are simple butt joints, glued and screwed. There are only two router bits necessary for the entire construction - a 3/8" straight bit and a 1/4" round over bit. The 3/8" bit will always be set to a depth of 3/8". On top of that, the bits are used sequentially: by the time you use the round over bit you will not have to go back to the straight bit at all.
5. Fairly Inexpensive - While I strongly recommend select grade lumber to ensure straight and square construction, the box does not use that much lumber. The most expensive item in the build is the foam for the inside padding.
2x2 select pine for the body of the case except for the top edge - I needed 2 eight foot pieces for my build
1x2 select pine for the lid and the top edge of the box - I needed three eight foot pieces for my build
One 2 ft. by 4 ft. piece of 1/4" chip board
One approx. 9 inch piece of 2x4, 2x6 or 2x8 depending on how deep your box is going to be
2 yards of burlap or whatever panel covering you want to use
One handle - Mine was salvaged from a suitcase I found at a thrift shop for four bucks
Foam - for my case I needed three inch foam for the inside of the case and one inch foam for the inside of the lid
Hot glue & glue gun
Strong spray adhesive
Four small L brackets
Two 1 1/2" x 3/8" corner braces - usually sold in packs of four
Assorted screws, #6 throughout the build
Four #6 pan head stainless steel machine screws approx. 2 inches long (depending on the handle you obtain) and four nylon insert locking nuts
Stain and finish to taste
Router with 3/8" straight bit and 1/4" round over bit
Miter or table saw
Dremel tool with carbide cutoff wheel
Clamps, strap clamp and L square
Box cutter with a long, segmented blade - or the longest razor edge you can find
Narrow wood chisel or Xacto knife with narrow (1/4") chisel blade
Step 1: Doing the Math - Calculating Your Custom Dimensions
Let's get the hard part out of the way first - figuring out exactly what size your box needs to be. Measure the size (length, width and depth) of the object you want to put in to the box. These will be the bases for calculating every dimension for your box.
Calculating the Foam: This project is designed to provide a minimum of one inch of foam protection on every side of your object, so add two inches to your length, two inches to your width and one inch to your depth. The resulting measurements will be the dimensions of the foam piece you will need to fill your box. You only add one inch to your depth because the inch of padding on top of your object will be provided by an inch of foam attached to the underside of the lid. The foam for your lid will be one inch thick, two inches wider than your object and two inches longer than your object.
Now for the precise dimensions for your frame and panel inserts. If you want to know how I came up with these figures just let me know. I think I bruised my brain in the process and will probably have to bruise it all over again if I try to explain it in full, but basing everything on the length, width and depth of the object you want to put in the box, here they are:
Exterior length of the finished box will be 4 1/2 inches longer than the length of your object.
Exterior width will be 4 1/2 inches wider then the width of your object.
Exterior depth (including lid) will be 3 1/8 inches greater than the depth of your object.
Now on to the individual pieces:
The longer pieces of the frame bottom, top and lid are cut to be 1 1/4 inches longer than the length of your object.
The shorter pieces of the frame bottom, top and lid are cut to be 4 1/4 inches longer than the width of your object.
The four corner posts are cut to be 1/8 of an inch longer than the depth of your object.
The top (lid) and bottom insert panels are both 1 3/4 inches wider than your object width and 1 3/4 inches longer than your object length.
The side panel on the side opposite the side with the handle is 1 3/4 inches taller than your object depth and 1 3/4 inches longer than your object length.
The two short side panels opposite each other on the box are 1 3/4 inches wider than your object width and 1 3/4 inches taller than your object depth.
The last two panels - on either side of the handle - are trickier. They are both 1 3/4 inches taller than the depth of your object, but here's the tricky part: their length is 1/2 the length of your object minus 1/2 the length of your handle brace plus 1 1/8 inches.
So there you have it. Just measure the length, width and depth of the object you want to schlep around in your box, plug those measurements into the calculations above, and you will have every measurement you need for the project. You could do this all ahead of time and make a chart of your measurements - which will probably save you some time in the long run - or you can refer back to this section every time you need to cut a particular piece and find out the dimensions you need for that particular piece.
Step 2: Building the Frame
I'm going to approach this from the bottom up, first building the bottom side of the box, then adding the posts at the four corners, then the top edge of the box and finally the lid. The good news is that all joints are butt joints, glued and screwed for strength. The bad news is that all sides of the box need to be constructed with either channels or grooves to hold the burlap inserts so that they will be removable and replaceable, so there's a lot of router work involved. But it's a good project for someone without much experience with a router because only two different bits are used, each bit is always set for the same depth, and there are no fancy or complex cuts of any kind.
The Frame Bottom: You need four pieces of 2x2 to form the bottom. For this case I needed two pieces 40 inches long and two pieces 7 inches long. Consult Step 1 to determine how long you need these pieces to be for your box. Either mark or make a mental note to establish which face of each 2x2 you're working on. You have:
(A) the side of the 2x2 that will be on the very bottom outside of the box,
(B) the side of the 2x2 that will be facing out on the sides of the box,
(C) the side of the 2x2 that will face up on the inside of the box, and
(D) the side that will face inward on the sides of the box. You won't have to do anything to sides (A) and (B) of these pieces.
The two long pieces are routed in the following manner: Side (C) - Using a 3/8 inch straight bit, cut a 3/8 inch deep channel the entire length of these pieces that is 3/8 of an inch from the outer edge.
Side D - With the same bit set to the same depth, make a series of passes to rout away all but the outer 3/8" of this side on both pieces. The resulting pieces will look like Figure 1 with dimensions shown in the Figure 1a cross section.
The two shorter pieces are routed exactly the same way except that you should begin your channels 1 inch from one end and end your channels 1 inch from the other end. In the 1 inch areas on either end of these pieces where you did not rout a channel. you need to rout a notch 3/8 of an inch from the end and 1/2 inch long. Each end of these pieces will look like Figure 2 with the dimensions shown in Figure 2a.
NOTE: In every case during the build where you are routing channels that do not go the entire length of the board, there is no need to square off the channel ends. All of these areas will be on the interior of the piece where they will not be seen and the measurements I've given are long enough so that the rounded edges do not interfere with the fit of the pieces. The diagrams all show squared channel ends, but as you will see in the photographs I have not actually squared any of them.
Lay out the four pieces on a flat surface, glue the butt ends of the longer pieces to the shorter ones and use a strap clamp and L square to clamp everything together until dry. If you don't have a strap clamp you can use whatever clamps you have, but rely heavily on your L square to make sure all your angles are a true 90 degrees. See Figure 3.
Once the glue has dried, reinforce each butt joint with a 2" screw, being careful to place the screws so that they don't emerge into the channels you've cut. I countersunk my screws and filled over with wood putty. ALWAYS drill pilot holes for your screws - it will help you get the screws in straight and drastically reduce the possibility of splitting the wood when you set the screw.
Step 3: The Frame Corner Posts
Since my box was fairly shallow, I only needed four 2x2 pieces, each 4 inches long for the sides. Refer to Step 1 to determine how long your corner posts should be. Again, the two sides of these 2x2s that will face toward the outside of the box can be labeled A nd B and you won't have to do anything to them. The sides that face inward can be labeled C and D and are both cut the same way. All four pieces are routed as follows:
Sides (C) and (D): Still using the 3/8" straight bit set at a depth of 3/8 of an inch, cut a channel the entire length of both sides that is 3/8 of an inch from the outer edge. Also use the router to cut a 3/8" by 3/8" notch into the inside corner of each piece the entire length of the piece. Your resulting posts should look like Figure 4 with the dimensions shown in Figure 4a.
Note on Design Decision: As you build your box you will notice that in every case the corner joints are butt joints. In addition, they are all designed so that the shorter (width) piece runs the entire width while the longer (length) piece runs up to the width pieces so that they wind up being three inches shorter than the total length of the box. There is a reason for this. The handle is mounted along the length - as it should be. This means that when you pick the box up by the handle, the weight of the box exerts force parallel to the line of the butt joints. The screws in those joints, however, are then perpendicular to the force of the box's weight. By designing the box in this fashion, it ensures that the force of the weight is exerted against the strongest possible configuration of the joint. If I had designed it the other way around, the weight would pull parallel to the screws, attempting to pull them right out of the wood. With the force of the weight pulling sideways against the screws it makes it much more difficult for anything to pull apart. Just thought you might want to know.
Step 4: The Frame Top
We're now working with 1x2s rather than the 2x2s we have used up to this point. You will need four pieces of 1x2 cut to the exact same lengths as the four pieces of 2x2 you used for the frame bottom, as you calculated in Step 1. You will only be routing these pieces on the side that faces down into the box.
The Longer Pieces: As you did with side (C) of the long pieces of the frame bottom, use the 3/8" straight bit to rout a 3/8" deep channel the entire length of these pieces that is 3/8 of an inch from the outer edge. The resulting piece is shown in Figure 6 ad 6a.
The Shorter Pieces: As with the shorter pieces of the frame bottom, rout a channel the same as you did for the shorter pieces, beginning the channel 1 inch in from the end and ending the channel 1 inch in from the other end. This channel is also 3/8 of an inch in from the outer edge. Also, in the 1 inch areas on either end of the short pieces where you did not rout a channel, you need to rout a notch 3/8 of an inch in from the end and 1/2 inch long. See Figure 7 and 7a.
Assemble (as in Figure 8), glue and clamp these four pieces with a strap clamp if you have one. If not, use regular clamps and rely on your L square to square everything up. Once the glue has fully dried, reinforce each end with a 2 inch screw through the outer edge of the short piece and into the long piece. You need to position the screw so that it does not come through the channels you cut or, of course, through the outer dimensions of the piece. If you're going to countersink the screws you should use a bit shorter screw - 1 3/4 inches or 1 1/2 inches - as long as it's long enough to engage the longer piece once you've countersunk it. Missing the channels you've cut means driving these screws at an angle, and I highly recommend that you mark a line on the piece at the desired angle and carefully drill a pilot hole at this angle. Don't worry if your screw slightly infringes on one of the channels - this area will not be seen in the finished piece and a bit of a cut through will not have a negative impact. See Figure 9.
Attaching the Frame Top to the Corner Posts: I want to make sure that you understand that when we attach the frame top to the corner posts they will be screwed together but not glued! This will allow you to unscrew the frame top and remove the side panels so that you can re-cover or replace them any time you want. We're not actually going to attach the frame top yet because we haven't made the panels we'll be inserting - just wanted to give you a heads up.
Step 5: The Lid
Again four pieces of 1x2 exactly the same lengths as you cut for the frame top.
The Longer Pieces: Not the same as the other long pieces - rout a 3/8 inch deep notch into one edge of the width running the entire length (Figure 10 and 10a).
The Shorter Pieces: Rout a 3/8 inch deep notch as you did for the long pieces - except start the notch 1 inch in from the end and stop it 1 inch short of the opposite end (Figure 11 and 11a).
Assemble and glue these pieces just like you did for the frame top. When the glue is dry, reinforce each corner with a screw like you did for the frame top, taking the same precautions as you did then.
Step 6: The Handle Base
Because the design of this box relies solely on the frame for its strength, we need a strong base for the handle that is firmly connected to the frame and will bear the weight of the box well. You'll need a piece that is the appropriate size for your build. For mine, I used a nine inch long piece of 2x4 cut down to 1 1/8 inches thick. The 3 1/2 inch width of the 2x4 was exactly the right measurement for mine - it needs to be 3/4 of an inch wider than the space between the frame bottom and the frame top. If you're making a deeper box - which you probably are - you'll need to start with a piece of 2x6 or 2x8 or more to have sufficient width. The 9 inch length I used was based on the handle I salvaged for the piece - 2 inches longer than the distance between the outside edges of the handle brackets. You'll be constructing a tongue and groove configuration to hold this piece between the frame bottom and the frame top.
Cutting the Handle Base: Rout a 3/8 inch notch along the length of the piece on both sides of the two long edges. This will produce a 3/8 inch wide "tongue" that will fit into the channels in the top and bottom frames. On the short edges, rout a 3/8 inch deep channel straight down the center of both edges. The resulting piece will look like Figure 12. Center this piece in the bottom frame channel on the side where you want the handle to be and glue and clamp it in place, checking with your L square for a true 90 degrees. DO NOT glue to the top frame. We'll wait to attach the handle until we have the panels inserted and the top frame screwed on.
Step 7: Making the Panels
You will need seven panels. Determine the dimensions of the panels by using the calculations in Step 1. The idea here is that each panel should slide (for the side panels) or drop (for the top and bottom panels) into place with about 1/8 inch leeway all around, which will mostly be taken up when you wrap the panels in whatever fabric you're going to use. If you've decided you want just plain wood surface rather than panels wrapped in fabric (or leather or vinyl or whatever) then you should cut your panels just a wee bit wider and longer to more snugly fit into their respective channels/notches.
Loosely wrap each panel in a piece of the fabric you're using and slide the panel into place to check for fit. If it's too tight, sand the appropriate edge down a bit and try again. If it's too loose, well, um - cut another panel and try again - the quarter inch chip board is really cheap!
Once you're satisfied with the fit of the panels it's time to wrap them. The process is the same for everything except the lid panel. For all but the lid, cut a piece of your cloth about two inches wider and longer than the panel. If it's wrinkled, steam iron it a bit to flatten it out. Lay the fabric on your work surface and lay the panel down on it. Begin with any edge and hot glue the fabric to the panel. Do a few inches at a time and, while the glue is still hot, press down on the glued area with a piece of scrap wood and wipe inward to flatten it out as much as possible. After the first edge is done, glue the opposite edge in the same manner, being sure to keep the fabric stretched a bit as you go so the finished side will be free of wrinkles. Cut the fabric in at the corners so you won't be doubling over when you glue the other two edges. Glue the opposite edges in the same fashion. When you're finished gluing the fabric onto the panel you may cut off any excess fabric on the inside with an Xacto knife. Do this for all six panels. The back sides should look like Figure 13.
The lid panel is a special case as the lid fits flush to the frame top and there is no interior space available for glue or fabric thickness. For this reason, the hot glue needs to be applied to the out-facing surface and the edge of the panel. Trouble is, you don't want the glue to show on the outside of the box which means you've only got roughly a 1/4 inch wide area around the side of the panel and the edge of the panel to apply glue. This means that if you want a great looking box you have to be very careful in gluing this panel. Instead of laying the fabric down and laying the panel on top of it, do it the other way around - with the panel on the bottom and the fabric on top. Mark the side of the panel at 1/4 inch all the way around if you think that will help your accuracy. Lay a line of glue a few inches long within the 1/4 inch space and press it down and around the edge with the piece of scrap wood. Continue this all the way around - one side, then the opposite side - until you have the lid fabric glued in place. Trim of any excess fabric. The lid panel edge should look like Figure 15. Put all the panels aside for now.
Step 8: Rounding Over the Outside Edges
It's time to attach the top frame to the corner posts - at least for a while. Use one 1 1/4 inch long screw at each corner, down through the top frame into each corner post. Remember that you have a screw running in the other direction at each corner of the top frame, so you need to sight your pilot hole carefully to miss both the screw that's already there and the channels in the bottom side of the top frame. You can do it - I have faith in you. You may have to angle these screws just a bit, but do not countersink them as they need to be removable. Just drive them as flush as possible. Actually, at this point you don't even have to tighten them down all the way because we're going to take the top off again after this step.
Sanding Flush: If there are any edges that are not fully flush, now is the time to sand them down to flush.
With the top frame attached and the joints sanded flush, use the 1/4 inch round over bit on the router to round all outward facing edges EXCEPT the bottom edge of the lid and the top edge of the frame top (see Figure 15). Don't forget to round over all the outer edges where the panels are going to be. After you've rounded all the edges, remove the frame top.
Stain and Finish: I know that your box isn't fully assembled, but now is the time to apply stain and finish as you like. I used a dark walnut stain and a 3X polycrylic finish on mine.
Step 9: Insert the Panels
Drop the bottom panel into place. Secure it in place with four small L brackets, one centered on each edge of the panel and screwed into the frame. See Figure 16.
Slide the side panels into place. They do not need to be secured because attaching the frame top will hold them in place.
Attach the top frame to the corner posts, tightening the screws to flush.
I used two corner brackets for securing the top panel to the lid. Using a Dremel tool with a carbide cutoff wheel, I cut each corner bracket off at the beginning of the leg to make four straight metal pieces as in Figure 17. Since the lid lies flush against the frame top, these pieces need to be set in grooves so that they are flush. Mark a place for each metal piece at the center of each inside edge of the lid. Use a small chisel or an Xacto knife with a narrow chisel blade to cut recesses into both the lid and the panel at these places deep enough for the bracket piece to sit flush. Your corner brackets probably came with 3/4 inch screws which are too long. Use a 1/2 inch long screw to secure each metal piece to the inside of the lid as in Figure 18. There is no need to screw the metal piece to the panel.
Step 10: Attach the Handle
This is going to depend on what sort of handle you managed to scrounge up. I strongly encourage a safari to the local thrift stores to find an old suitcase or briefcase you can salvage. I happened on a suitcase at my second stop that had an excellent handle and got it for four bucks. You'll almost certainly have to improvise here according to the handle you manage to find and I'll describe the process I went through, but the point to this step is to attach the handle securely in a manner that will not allow it to come loose.
I brought the suitcase home and began disassembling it to remove the handle. The brackets that held the handle to the suitcase were also serviceable. I discovered that the brackets were attached by a tang that was driven through an aluminum strip that formed the edge of the suitcase - sort of like a huge staple. I straightened out the tangs and pulled the handle off. I also kept a strip of the aluminum edging that would be useful in the build. Next I cut the tangs off the handle brackets. I then drilled a 5/32" hole into each end of the brackets. I set the handle and brackets down on the handle brace and marked the position of the holes I had drilled in the brackets. I drilled a 5/32" hole at each of these marks down through the handle brace. Next I marked and drilled the piece of aluminum I had kept from the disassembly of the suitcase to correspond to the position of the four holes I had just drilled. I placed the handle with the brackets on the handle brace, ran #6 pan head stainless steel 2 inch long screws down through the brackets, through the holes in the handle brace and through the aluminum strip on the inside of the box and secured the screws with nylon insert lock nuts. Mission accomplished. Figure 19 shows the handle brackets with the screws in place and Figure 20 shows the inside of the box with the aluminum strip in place and the nylon insert lock nuts secured. Since the build is pine and the screws and nuts are pretty small, you need some sort of piece on the underside of this assembly to keep the weight of the box from gradually pulling the screws right through the pine. The aluminum strip served the purpose nicely, distributing the force of the weight across the length and width of the metal strip.
Step 11: Attaching the Lid
Hinges: Two hinges, evenly spaced along the back. Didn't even notch them in. Figure 21. 'Nuff said.
Latches: Since the construction is frame, there are only three places to put latches - one on each post and one at the center on the handle brace. I decided I only needed the two latches at the posts. Very small latches, very small screws. This is one place where you don't really need pilot holes, but at least use a small nail to make an indent where you want to start the screws to help them go in straight. Depending on how flush your lid and frame top are, you may need to notch the upper part of the latch in a bit so that it will catch properly. You may choose a hook-type latch which would probably be a bit more secure and less effort to install properly, but I thought the type of latch I used looked better with my overall design. See Figure 22.
Step 12: Cutting and Installing the Foam
The box is now completely assembled and all that's left is cutting and fitting the foam for the inside. Warning - foam is outrageously expensive! I don't know why, but it is. I got mine from the local Joann Fabrics store - the kind they use to stuff pillows and furniture cushions and such. The dimensions of my box dictated that I needed a three inch thick piece for the inside of the box and a one inch piece for the inside of the lid. You can use multiple pieces to construct thicker inserts, gluing them together with high-strength spray adhesive. You need two pieces of foam - one to fit into the body of the box - this needs to be thick enough to fill the box to within one inch of the top of the frame top. The second piece needs to be one inch thick and the same dimensions as your lid panel insert. Since the foam is so pricey, cutting it is nervous time. You only get one chance. First, you need to cut the foam to the approximate inside dimensions of your box. I used one of the box cutters that has long, segmented blades that let you break off a piece to get a new edge (Figure 23). I took the entire blade out and used it without the holder. This gave me about a four inch long blade to cut my three inch thick foam. Some important tips here: Cut with long, slow strokes, trying as hard as you can to keep your cutting edge perpendicular to the foam. Let the sharpness of the blade do the work, applying almost no pressure. This will give you the straightest, cleanest possible cut.
Measure the interior dimensions of your box. Mark the foam and cut accordingly. Now trace an outline of the instrument for which you're building the box onto cardboard and cut it out. Place the cardboard centered on your foam piece and trace it onto the foam. DO NOT put the foam into the box to do this step - I'll explain why in a minute. Carefully cut the outline all the way through the foam, again trying your best to keep the blade perfectly perpendicular to the foam and letting the blade do the work. I recommend standing the foam up so you can easily cut all the way through it. It is also very important to cut this as a single piece - don't cut portions of it out - so that the piece you have left over looks like a silhouette of the instrument. Remove and save the piece you just cut out.
If there is room in the box you might also cut a hole for holding accessories (picks, reeds, straps, whatever) at this time. I angled my cut-out so that I had lots of room on one side of the neck to cut an accessories compartment.
Now place the foam in the box. You'll immediately notice that you just screwed everything up. Not really, but the compression resulting from fitting the foam in the box (and you should have cut the foam so there is at least some compression to give it all some degree of firmness) has caused your instrument outline to squish in on itself. Not to worry. Take the cardboard template you used to cut the foam and place it over the squished-in opening in the boxed foam. Mark the outline and once again, remove the foam from the box, carefully cut along the lines - which, now that the foam is out of the box, looks like a terribly overweight version of your instrument. Don't worry - it will slim down again once you put the foam back in the box. Don't you wish it was that easy for us? The reason you did it this way is because you wanted the silhouette piece you made on the first cutting - because you're going to put part of it back in the box. Put your re-cut foam back in the box.
Take the silhouette and - once again carefully and smoothly - cut a one inch thick (or however thick you want your bottom padding to be) slab off of it. This piece will now fit nicely into the re-cut hole you made in the foam. Push it into place and it will look similar to Figure 24. (Note: If you're building for something like a guitar, you can contour this piece as you cut it to put thicker padding under the neck, for example.) You can now fit your instrument into the box - if you've cut properly it should fit snugly into the foam and be flush with the top surface of the foam. If your instrument rises above the surrounding foam, you need to take the silhouette piece out and cut it down a bit more so the instrument will be flush with the top of the foam when it's resting in place.
Cutting the Foam for the Lid: Mark the one inch thick piece of foam to the size of the lid insert panel and carefully cut to these dimensions. Now go back and cut again so that you have a 30-45 degree angle all the way around the edge. With the insert panel in place on the lid, mask around the panel then spray the panel with a high-strength adhesive spray. Remove the masking, place the piece of foam into the box and close the lid. Open the lid and the foam will have adhered to the insert panel. Smooth the foam firmly down on the panel so that it is securely fixed to the panel.
A Special Note on Frugality: Like I said, foam is ridiculously expensive, but you can do a lot to fix this. I mentioned that I buy things like this at our local Joann Fabrics. What I did not mention is that Joann Fabrics ALWAYS has sales going on. I highly recommend - no, scratch that - I DEMAND that you take advantage of this fact. Any given week of the year, Joann Fabrics will have coupons both in store and online for either 40% or 50% off the cost of any one regularly priced item. Foam is seldom on sale, so wait for the 50% off coupon and go grab your thick foam. Then go back the next day and grab your one inch foam. I'm not kidding. The three inch thick piece for my build would have cost me over 40 bucks without a coupon - and since I'm a senior citizen I went on senior's day and got both 50% off and another 20% off as a senior. If you don't do it this way then you probably have a lot more money than I do.
That's it - your instrument travel box is complete and I hope it looks every bit as great as Joe's - he was happy beyond words with it. I know this has been a long Instructable but I hope you've found it worthwhile and realize how easy it will be to adapt it to any dimensions you care to use. If you have any questions at all feel free to ask, and...