1/2" plywood (a half sheet will do, use a nice clean piece) oak,maple,birch, whatever you like
1/4" plywood (one piece 12"x18", you can buy a 2'x2' at the big box store)
1/8" Baltic birch plywood (this is the tough one to find, try a real lumber yard or plywood supply place, you need one piece 12"x18")
Scrap wood (enough to make 3 blocks, say around 2"x3")
Oak cove moulding (buy an 8' piece) for the 'frame' and corner supports
#6 x 1/2" wood screws (I use antiqued brass or copper for looks) about 16
1" dowel, about 12" long (I use 1" oak, but if you have a broomstick or toilet plunger handle you'd rather use go nuts)
1 drum snare (aka strainer), cut right down the middle + 2 little wood screws to secure snare to dowel
1 cup hook (or similar hook with a screw)
1 small turnbuckle with a loop and hook
1/16" metal cable (sold by the foot, grab 3') plus a package of ferrules for 1/16" wire
Clamps (2 ratchet straps come in handy as well)
Stain or finish or poly or lacquer, your pick
Step 1: Step 1: Build-a-box
Okay, so the first thing you need is a box. Most of the cajons you'll find are about 18"x12"x12", and that's a good place to start. It's like a medium Tshirt- it'll fit most people fine. If you're taller or shorter or longer-legged you may consider making it taller or shorter of course, or if you're shooting for a different sound. I urge you to make sure that it's not too tall to sit on comfortably or to wide to wrap your legs around.
First we'll take the 1/2" plywood and with a large square and pencil lay out the first side piece - 12"x18". Make sure when you lay out your cuts you've got the grain running uniformly around the box, I like to have the grain vertical up n down the sides and then side to side on the top piece and bottom piece. I don't think it'd matter structurally, I think it looks good to have the grain appear continuous. I use a circular saw with a clamped down straight edge OR a table saw to cut the plywood, depends on the size of the piece...a full sheet is a bit big for my table saw setup. Once you've got one side cut, I lay it down and trace it, and then cut out my second side to get the 2 sides matched perfectly (keep in mind what sides which when you trace and cut, plywood has one good side so it's gotta be cut with what side will face out in the front of your mind). Follow these same steps and cut 2 pieces for top + bottom, 12"x12" . Now we're gonna rabbit the top inside edge and bottom inside edge of the side pieces. You want to make a little "shelf" for the top and bottom pieces, so it sits together nicely. I take a piece of the 1/2" plywood and lay it perpendicular right up to the top/bottom edge of the side piece and make a pencil line right across...this way your rabbit is the exact thickness of the piece that'll sit in it. Adjust your table saw blade (assuming you haven't a router) to go just halfway or so into the side pieces, I try to get it right to the beginning of a layer in the plywood for uniformity. Make a pass right on your pencil line at all four edges (top and bottom of both side pieces on the inside) and then keep moving towards the edge. Of course, if you have a more sophisticated means of joinery at your disposal, all the better...work with what ya got. We are ready to glue! Lay the 4 pieces of your box in position face down on a flat surface and dry fit it. It helps to have help for this step because you have to work fast. Apply a fair amount of wood glue all over the rabbiitted edges and fit all your pieces together. Keep a square nearby to keep popping it into the inside corners to keep your box true. What I do is wrap 2 ratchet straps around it and crank em down tight (I slip little scraps of wood under the metal bits to keep the wood nice). Wipe away any squeezed out glue as you go. Keep checking for square!
Step 2: Step 2: Yo Don't Front, I Got Your Back
Now that we have a box we can mark and cut our back piece and our tapa- the front, or playing surface. Lay your 1/4" plywood face down and lay the box on it (back side down) and trace out your back piece. Make sure you cut true to the line or a little big, you can always sand some overhang away but you can't make it grow!
Now for the tapa- lay the 1/8" plywood face down and lay the box face down onto it , trace out your drum surface. Again, cut it carefully insuring that it's just right or bigger. Because you have to cut with the "good" side underneath, which is generally not ideal, you may be likely to get some blowout and splintering. First off, you can usually get your pieces with only 2 cuts...assuming you have 2 good edges on your plywood to work with,you can put the box right into a corner to trace, so that's 2 sides done. I like to lay out some wide masking tape on the good side (you can guesstimate it by looking at your pencil outline and lining up the tape underneath) right across all the cuts I have to make. It helps keep your cuts clean and comes right off. Once the front and back pieces are cut, I like to make my soundhole in the back piece. It's up to you if you want to do it now, or wait till the back piece is glued in place and then cut out your hole. I steer clear of the boring old perfect circle and do something cool... Maybe an organic shape that mimics the grain in the wood, or a symbol or shape you like, anything you can cut out with a jigsaw is fair game!
Step 3: Step 3: I Was Framed
Once your box has dried, we can build a frame inside the face that the tapa will screw into. Nows a good time to use an electric sander to make sure we have nice, flat, even surfaces at the front and back so our pieces sit flush against all edges. Be careful not to make any dips, we need straight edges...the plywood back piece will conform a little and the tapa really sits on the frame, but the straighter your surfaces the better.
Okay,the frame...I use an oak cove molding (3/4") ,it's perfect for the job and I just butt the pieces, no miter joints. Measure the inside dimension across the top and bottom of the box, and cut 2 pieces of oak to fit nice and tight. Glue them in place and clamp em down...MAKE SURE that the oak pieces are juuuuust a hair proud of the face edge of the box. It's crucial that the tapa makes contact with the oak frame ALL around so it cannot be recessed even a tiny bit. Once these 2 pieces are secure, measure and cut the 2 side pieces of oak, glue and clamp. Pay attention here to nice clean joins and again- make sure the oak frame is the foremost surface all around...the tapa doesn't screw into or touch the plywood,it screws into and sits tight on the oak frame.
Step 4: Step 4: There's a Snare in My Soup
Ok, this is what makes a snare cajon a SNARE cajon- the snare! I have tried/played lotsa cajons and to my ear, the best sound is from an actual drum snare...it really gives you that drum-kit-in-a-box sound that I like in a cajon. I've been using 14", 20 strand snare but feel free to use what's handy. I cut the snare wire right across the middle so I always get 2 cajons worth from 1 drum snare. I use a Dremel, tape the snare down to a scrap-piece, draw a pencil line on the tape across the middle and cut it neatly. This "half-a-snare" will then get mounted to the dowel with 2 small wood screws.
The mounting "system" for the snare is pretty simple but ingenious, sadly I can't take credit for it but I can tell you it works! For this we need 3 smallish blocks of solid wood and a solid wood dowel. I use 1" oak dowel and some 3/4" thick maple, but almost anything will do. The 3 blocks can all be the same size, say 2"x3". 2 of these will go on the inner sides of the box just behind the frame to hold the dowel, so they need holes for the dowel to sit in. Find the center of your 2 blocks,mark it, and then use a Forstner or spade bit to drill a hole about halfway into the blocks (if using a 1" dowel,use a 1" bit,and so on). Then on one block we need to make a channel from the hole to the bottom edge, so we can get the dowel in and out. Once you've got the 2 blocks done and the snare mounted to the dowel, you can kinda dry fit the blocks and figure out how long to cut the dowel AND where to glue the blocks so that the snare contacts the tapa right at the top.
The third block is gonna be glued to the "ceiling" of the box, but first you need to drill a pilot hole in the center where the hook will go. It's crucial to drill the pilot hole so that the wood doesn't split when we screw in the hook. Glue this block with the hook in it towards the back of the box, centered, and hang your small turnbuckle from the hook. Now we need to drill a small hole through the dowel just big enough to fit a 1/16" wire...it needs to be in the middle of the dowel lengthwise BUT off-center widthwise. When we feed a wire through that off center hole and pull up on it, it will make the dowel want to roll forward, pressing the snare against the tapa. So feed your wire into the hole from the bottom up through the top, and either tie a knot or crimp a ferrule on top. The other end of the wire needs a loop, so put your ferrule on the wire and loop it around but before you crimp it figure the length by attaching the loop to the turnbuckle (loosen the turnbuckle a lot to start so you can tighten it later to add tension). Also, lube up the threads on the turnbuckle so it turns nice and smooth, it makes it easier to adjust on the fly by reaching in through the soundhole.
Step 5: Step 5: Just Glue It, Let's Do It
Ok, we've got everything made, now we just need to do the finishing touches. We can start by gluing on the back piece. Dry fit it and make sure all is well, and then glue it up and clamp it down. You want a nice, airtight seal here so make sure it's clamped well. Let it dry overnight.
Now to secure the tapa to the frame... (remove the dowel/snare for now, it'll go in at the end) Lay your tapa piece in place and mark your spots to drill holes for the screws. There are many variations on the pattern of screws, everyone does it differently. I like to leave the top corners unscrewed so you can get some 'slap' from wood on wood in the corners. Whatever pattern you pick, make sure your holes are marked to sit in the center of the oak frame and NOT on the plywood. The topmost screws are going to be right where your hands will hit for a snare sound, so ideally you'd like those screws to be flush for comfort. B VERY careful when countersinking them because you've only got 1/8" of wood...it's super easy to go right through. I like to use an antiqued copper or brass wood screw so it looks nice (I go with #6x1/2") they're usually used for cabinets where the screws are visible.
Go ahead and drill your screw holes through the tapa and oak frame (making sure the tapa is down tight and not moving at all while you drill). You can screw the tapa down now!
Step 6: Step 6: Smooth It Out Now
alrighty, we've got the back glued on, the tapa screwed on and now we need to make this box nice and shmoove. First I sand down any overlap on the back piece and the tapa so everything's flush. Be careful on the top/bottom edges,you don't want any splintering or anything...the sides are easy because they run with the grain.
Once you have everything flush, you want to really knock down the edges of the box as well as the back top comers. I use a sander and round over the edges, and grind down those back corners pretty aggressively. You can use a rasp if you have one to take off the corners, I use 80 grit paper. You slide onto the cajon from the back and them sit straddling it,so you want those top edges to have a decent radius and back corners to be rounded and smooth so it's comfy to sit and play. On the bottom you can be a little less picky since it's just for looks , so I just barely round it and break the corner on bottom.
Now it's just sand,sand, and sand some more...
Step 7: Step 7: Are You Finished?
if you've got all your corners and edges the way you want and everything's all nice and flush, you can unscrew the tapa and take it off. It's time to finish this bad hombre!
I like to use a spray bottle of clean water and spray a very fine mist all over the outside surfaces and the front of the tapa. The water will raise the grain, which we will then sand down. It helps to do this first so that whatever stain or finish you use doesn't raise the grain so much (once raised, the grain will not raise very much next time)
I recommend treating the tapa with something that will really soak in and "harden" the wood. If you're going to stain the tapa, stain it first and then treat it with whatever you chose. I've used Waterlox on the tapa with success both with and without stain. I do both the front and back of the tapa. As for the box part of the cajon, it's personal preference. I think it looks good to contrast the tapa with the box, so I'll stain the tapa but leave the box natural or vice versa. You want the tapa super smooth when you're done... Once it's all stained/oiled up, I spray the tapa with clean soapy water and wet sand it with 1200 grit.
Some builders like to coat the inside of the box with something, supposedly helping it to resonate by making the surface less absorptive. I have tried it, but I'm not sure if there's a difference or not. If you'd like to try it, a mixture of wood glue and water can be painted on with a brush all over the inside of the box. I do like to hit all the inside corners with some caulk or silicone just to get it super airtight all over. Just like a speaker box, except you make the bass!
Ply woods (particularly Birch) can be finicky about staining and prone to splotching and such so I personally stay away from water-based stains. I may try one out, just because lots of the cool colors are in the water based stains, but I can vouch for the successful use of oil based products. Other than that, there's tons of info out there about staining and finishing and such so I won't get into all that here...
Get creative, stencil, draw, spraypaint, do what you like and make it your own.
Step 8: Step 8: Drop Some Fresh Beats
hey, YOURE DONE! Sweet, now it's time to play it. Well, I can't help you there but there are a zillion good tutorials online to get you started. And virtuoso or not, it's always fun to play something you made yourself. So play it loud my friend, and be proud!
Thanks for looking, I'd be more than happy to hear any questions/comments and of course I'd love to see what you've made!