gdguarino was heard to mutter:

For the uninitiated, a cajon is a percussion instrument, essentially a wooden box with one thin side and a hole in the opposite side.
I'm a keyboard player, but have recently developed a hankering to dabble in percussion. Plus, I have a pile plywood scraps lying around.

I've seen various plans online, and I'm sure that there are any number of sound-related variables to consider, but I'm mostly here
to ask about structural strength.

One plan I saw calls for a box 12"x12"x18" tall, made with 1/2" plywood. The wrinkle is, one plays a cajon while *sitting* on it. And
some of us wanna-be percussionists have put on a few pounds over a lifetime. I'm wondering about the strength of what is effectively
a five-sided 1/2" ply box (the front side is made with very thin ply, maybe 1/8")for say, 250 pounds. Will it need corner braces? Or 3/4" ply?

Last year I finally got around to purchase a Cajon on discount. I had
searched around locally and found only one model that I truly liked
which was at Sam Ash. I played around with it for two weeks and
decided I still was not satisfied with the sound. I decided maybe this
summer I would try and build my own.

I searched for plans and ideas and there are lots out there. Some
really good YouTube videos too. Many I have watched use plywood with
good results. Including weight handling. Check YouTube for ideas.