How To Build a Cajon - Finishing Touches PDF Print E-mail
Written by Casey   
Friday, August 14 2009 14:43
Article Index
How To Build a Cajon
Goals
Wood and Frame
Hole
Gluing
Door and Feet
Snares
Finishing Touches
Micing and Audio
Other Links
Readers Respond
License
All Pages

Ocaña suggests you take a swallow before you hit it the first time since you may well be disappointed. It's true. But play around with it, stick it in a corner and play it, get used to your tapa and how to strike it, and it's true character will likely reveal itself to be a lot better than your first impression. After giving it some time and practice, i have grown to love this one as it is, and i haven't taken it much further than the original design (e.g. by coating the inside with glue as Ocaña suggests, trying other tapas, placing wood inside to direct the waves, whatever). The snare, though: You will probably want to spend some time on your snare.

Ocaña recommends not gluing the tapa. Apparently some builders glue it, probably because it's easier to make but possibly because it seals better. Many cajon players, myself included, like the top corners of the tapa to be free (thus the lack of screws there, or with glued tapas, the lack of glue in the top third) in order to get a slapping sound as the tapa corner hits the frame (Inserting paper shims in the corners to raise them up a tad may help you get a good corner sound.) So the seal may not be as gravely important as it's made out to be, but perhaps the overall seal over the perimeter of the tapa really does matter. Having the corners lifted with shims in conjunction with slightly loosening the screws that abut the corners didn't seem to affect the bass sound much, as compared to no shims and all the screws tightened.

Ocaña recommends being generous with the number of screws. The tapa of this cajon lifts off a tiny amount at the edges, probably because of a slight, natural deformation from the tension of the screws. I am confident that the seal is nonetheless good. Drilling pilot holes is probably a good idea for the tapa screws to as to avoid splitting the hardwood frame. Before affixing the tapa, of course, you want to ensure (through sanding, if necessary) that the internal frame is appropriately flush with the edges of the plywood sides, top, and bottom. (I may even have tapered the plywood back a hair to make sure that the tapa contacted the frame fully, which may also help explain the slight gap between the tapa and the plywood.)

 

Straight-up organic locally-grown homemade fresh-squozed beet juice was used to dye the wood. As for the tapa, Ocaña recommends rigid finishes only as oil would soften or dampen the resonance. Not sure if he feels the same about the other faces: I think he advocates using similarly rigid finishes on the interior at least (or the glue method he described). It's hard to imagine that it matters on the external non-tapa faces. Anyway, given the horrid environmental and health aspects of most finishes, beet juice was used. As for finishing the tapa, it was left unfinished and we'll let nature slowly break down the plywood (which, of course, is itself full of toxic glues and will probably last lifetimes.) After the beet juice dried, a light pass with unrefined walnut oil, which is purported to be a "true drying finish", and is about as natural as it gets in that department, was applied. The inside is also unfinished.

Beet juice fades very quickly. A test piece faded dramatically after a week or two of mild sunlight. But it's beautiful, and you can always add another coat. Once totally dry it does not rub off on your clothes, though if it got wet it may well. I don't know if the walnut oil will make it harder to re-juice. I keep it under a cloth when not playing it in the hopes that the fading has more to do with ultraviolet light. Maybe the oil will help if in fact it has more to do with oxidation. Time will tell. After three weeks it still looks very strong, as opposed to the test piece, so maybe the combination of oil and storing under a cloth will work. Update: After 1 year the cajon was still nice and red, though it could maybe have used a fresh coat. After 2+ years it's more pinkish now. Still nice enough, but definitely ready for another juicing. This whole time i've kept a cloth on it to cut down on the UV.

 

The finish work basically involved making the edges meet up through the magic of sanding. All three of the top non-tapa edges were all generously rounded - it's definitely worth it! After sanding, the moisture in the beet juice will cause the wood to regain a rough texture, so don't spend too much time making it perfectly smooth, as obsessively fun as that is. Apparently you can sand, wet down the surface with water to bring out the grain, let it dry, then sand again, and this will cut down on the roughening phenomena.

Isn't it so beautiful?

 


Last Updated on Thursday, April 08 2010 16:01
 

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Comments (16)
16 Tuesday, September 07 2010 10:41
Celeste
Thank you for all the info ad the pictures. I been looking around to see how a cajon is made and this page has helped me a lot. Great work.
15 Friday, September 03 2010 10:51
mgmt
@Job:

Re: wood, see page 3, called, cleverly, "Wood and Frame": http://caseyconnor.org/jl/cajon?start=2 -- As far as species of wood are concerned, I doubt it makes much difference, since we're talking about laminate plywood here.

Re: Ocana, see the intro page, "Germán Ocaña".
14 Friday, September 03 2010 01:18
Job van Dieten
thank you for the advice. i have one more question. are there certain types of wood trhat are more preferable or better-sounding than others. And may i ask who/what Ocana is, i have to acredit this in my bibliography.
...
13 Wednesday, August 11 2010 17:25
mgmt
> what is the thickness for the tapa? im trying to build this cajon drum but im having problems making the snare thing.

Hi -

For the tapa, see page 3, called, cleverly, "wood and frame": http://caseyconnor.org/jl/cajon?start=2

For the snares, see page 7, called, cleverly, "snares": http://caseyconnor.org/jl/cajon?start=6

Good luck,
-Casey
12 Wednesday, August 11 2010 17:13
joe
what is the thickness for the tapa? im trying to build this cajon drum but im having problems making the snare thing.
11 Wednesday, July 28 2010 10:34
mgmt
Hi -

@Job - see http://caseyconnor.org/jl/cajon?start=3 for info about the hole size issues. The size doesn't seem to matter so much, in my experience. The function of the hole is to "let the bass out", in a simple sense; the cajon "kick" sound is making a "thud" wavefront. Without the hole, the thud hangs out inside the box and doesn't come across as loudly. My personal conviction (as explained at that link) is that the hole isn't part of a "Helmholtz" model, where it "tunes" an air spring, so much as it just prevents the air pressure of the internal space from preventing the tapa from moving and allows the thud wavefront to escape. If the tapa vibrated like a traditional drum head membrane, then the hole might be relevant, as when playing a djembe you can insert or remove a fist in the hole to change the pitch of the drum.

Gluing/nailing: see http://caseyconnor.org/jl/cajon?start=4 -- nailing or screwing into the edge of standard laminate plywood doesn't really work, so you basically need to glue. Ocana also recommends this for the sake of a good air seal via the glue. The exception, sometimes, is the tapa, which you screw into the frame (the frame is in turn glued to the inside of the plywood). Some people also glue the tapa, but i prefer to leave mine removable.

@Richard - Yeah, generally the back panel is the same as the sides, with 12mm or thicker plywood (glued all around). It's important that the cajon be sturdy/rigid. Regarding the snares, see http://caseyconnor.org/jl/cajon?start=6 ... I agree that the string-snares are not satisfying. There are a number of other ideas on that page, as well as links.

Glad the site is helpful,
-Casey
10 Wednesday, July 28 2010 00:41
Job van Dieten
Is it better to glue or nail the cajon together? And why?
9 Wednesday, July 28 2010 00:37
Job van Dieten
I am designing and creating a cajon for a school project neccesarry to finish the school and get my diploma. what is the relation between the size of the cajon and the hole? is the function of the hole to amplify the sound or to add an other sound function?
8 Thursday, July 15 2010 08:32
Richard Cowling
I built a Cajon 3 weeks ago, using plywood I had around. 12mm for sides, top and bottom, 3.6 mm for tapa and back panel, but the back panel was doubled up. really just a trial and will buy some better quality faced ply one day. I took some ideas from this site so thank you: I though I would respond with what I discovered.

My original design borrowed your first snare idea, but across one corner only thinking that I could have a 'slap + snare' corner plus a 'slap only' corner. The snares were not very successful: if given a lot of tension they produced a distracting sort of hum. Now I have them slack and with a few loose wires wrapped around which is OK played lightly but I am working on alternatives and will post here if I have a breakthrough.

I did find that there was a nasty resonance from the back panel even though it was well screwed on, and cured that by using frameseal (the stuff that goes around window frames) applied from the inside (with the Tapa removed). I also glued a chunk of MDF to the inside of the back panel to deaden it. The bass seemed more solid after that.

Just for fun, we put an ordinary cheap PC mic inside it and played it through a computer sound card: if you want to hear that, and see the cajon, go to youtube.com/expertanswers.

Even without a microphone I am amazed at the range of sounds and dynamics you can extract from what is just a box.
7 Wednesday, May 19 2010 19:56
Zack
Nate, i would like to use the same technique you used if you say that it is a better design. Let me know! Thanks
6 Monday, May 17 2010 18:15
CaseyC
Thanks David - please do report back if you do this experiment. My impression is that the helmholtz model doesn't apply very well; i originally kept the hole cut-out from my cajon with the idea that i would incorporate it as a "slide" over the hole, allowing me to vary the effective hole size and thus the kick pitch. In practice, it made no difference in the pitch (like, at all). In other words, i'm not sure there is really any resonance or vibration happening with the tapa; it seems like it is more of a "thud" wavefront. Perhaps with tapas of other sorts this would be different. Perhaps a tube would have a more dramatic influence. I'm curious too, so i look forward to anything you come up with. Thanks!
5 Monday, May 17 2010 13:56
David Hancock
I was wondering if it wouldn't make more sense to do something with the hole similar to what someone would do when designing a speaker and tune the cajon with a port tube. This would make it more of a Helmholtz resonator. The air inside the port tube would resonate and provide a boost in low end frequency depending on the length and diameter of the port. For instance, if the interior volume of the cajon is roughly 1.9 cu. ft. then a 3" inside diameter port with a length of 8.5" would have a tuning frequency of 30 Hz. There would be a 12 decibel per octave roll off below that frequency. At those frequencies it would not matter where the port hole was located as the wavelengths are quite long at those frequencies. I do plan on building one to experiment with this summer. I will be sure to keep you informed of my progress.
4 Tuesday, April 20 2010 00:55
Dietz
I would be interested in more exact instructions Nate
Thanks
3 Monday, March 22 2010 16:02
mgmt
Sorry, had an issue with the commenting system (fixed now). Here are two comments in response to "instead of using guitar stirngs or a snare":

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I am thinking about building my own canjon and your experience will be very helpful I think! Can't you create a blog or something like that and share your experience? I'm sure there is many people that will appreciate!
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Yeah same here!
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-Casey
2 Sunday, February 07 2010 11:14
Gervacio Garcia
I was recently introduced to this instrument by a friend from my church, I decided to build a cajon based on the dimensions and features from the one we have at church and from the information you have posted.
Like i said am not a pro or anything else but love the sound of this instrument.
The one i built is 18 inches tall by 12 inches wide. i did not install any type of resonating devices in it, just pure sound from what the tapa (face) would make.
I use it for the first time today at church, like i said am not a pro, but i got good results.
Thank you for all the vital information you have share with everybody else.

Thanks
1 Thursday, January 28 2010 05:13
nate
a different way of making your own cajon is too use small pieces of bamboo or just a bunch of wooden rods they should be a little more than a quarter of the length of your cajon and about the size of a instide of a bic pen(the part that hold the ink), basically you run them up and down which would be perpendicular from the bottom and top of your cajon. So you take your bamboo or wood sticks and line them up all nice on the inside of the front side, after you have them lined you want to glue them at the bottom of the sticks(the side closest to the ground)leave the top unglued so the bamboo has room to reverberate then you take a piece of wood that will connect to the front (basically this piece of wood is used to hold the bamboo in place it is placed parrallel to the floor a little less than half of the way up the bamboo sticks connect that piece to the frame you made that fits the front (where most directions tell you to connect the guitar strings). Another thing to keep in mind is that the front top of your cajon should have some play in it basically you should have screws that can adjust the front to get the snare sound. I WOULD HIGHLY RECOMMEND LOOKING?PLAYING A CAJON AT YOUR LOCAL MUSIC STORE (hopefully you are lucky enough to have a store that carries a cajon or two) Basically i built my first cajon following the instructions above plus a little extra except i used snare wires instead of guitar strings, then i had the pleasure of playing a cajon in dales drums and i examined the build of the ones there. Building my next cajon i had a much better design and got much better results. if you would like more exact instructions let me know i would be happy to help.