Breathable fabric for protecting musical instruments?

[BBQchicken]

First time Burner here! I'd like to bring my cajon to the burn, but I'm worried about the inside of the instrument getting filled to the brim with playa dust. Is there any good fabric or material I can use to cover the sound hole in the back that won't keep all the air in and deaden the sound?

[Eric]

Do not bring an instrument to the playa & expect it to come home the same. Period.
It's not just the dust, there's also the heat & the fact the dust is a desiccant, so it will be sucking moisture out of the wood your cajon is made from - but if it gets wet, say from sweaty hands or a some spilled water, it turns into a really sticky clay. It's not sand, it's not really dust - think of it as extremely fine talcum powder, and it will get everywhere, no matter what you do to try to avoid that.

If you want to bring an instrument to play, your best bet is to find a second hand one or cheap version you don't care about and bring that. Hundreds of people do it, and there are marching bands, live blues, live bluegrass, etc, out there, all playing away and sounding great.

Never ever ever bring anything you can't afford to lose - or don't want to lose - to the playa. Especially if it would be expensive to replace.

[BBadger]

Probably not, otherwise people would have covered every screen, air intake, or whatever with it already. The dust is fine enough that it'll go through everything that would provide sufficient airflow for an instrument (I doubt a HEPA filter would work on your instrument). You could try some panty hose or something for a first line of defense, but it's not going to keep your instrument clean, and may deaden the sound slightly.

You'll probably have to accept that your instrument is going to, at the very least, get covered in dust. It may even get ruined by the playa dust, or be permanently imbued by the dust. The dust is not your typical dirt. It's an alkaline dust that sticks to everything that is hard to remove without a slightly acidic solution. An air compressor spraying out the dust will help get rid of the loose stuff, but there will always be that coating.

I wouldn't bring anything that you wouldn't be heartbroken to have permanently scarred or wrecked by the playa.

[gaminwench]

I agree with Eric and Bbadger.

And

Many bring instruments to the playa, I have done so myself.
Do you have a case for your cajon?
If not, get one.
The dust issue will be minimal if you only take it out of the case to play it.
I wouldn't worry about covering the sound hole.
When you store it, wipe it down with a vinegar/water solution and put a moist sponge in an open baggie inside the instrument.
Should be okay.

[Token]

I'd be more worried about warpage on account of the radically low humidity.

Depends on how classy of a Cajon you want to bring out. If you have a junk-er or can quick build one from pressboard or mdf, might be better.

[Elorrum]

I have a small guitar and I keep it in the shade in a pillowcase... and then in the car after dark. It's a little beater that I've consigned to a burning man eventuality, but it keeps coming home with me, gets wiped down and keeps on keeping on.

[Canoe]

BBQchicken: When Eric raises his head to reply, it's very advisable to pay attention to what he has to say.
Leave the good one at home.

That said, you've enough time to build a cajon, then before the back goes on, seal it inside and out with something that is water and water vapour impermeable. I'm thinking tung oil or epoxy resin. Treat the back the same way. Let it all completely cure, then assemble. It will not sound the same (as violin varnish changes the velocity in the wood vs varnish), but sealed that way it should be playable & survive.

For the assembly, do NOT use hide glue, no matter how traditional that may be for instruments. Violin family instruments assembled with hide glue then left in a car in the sun can be heated to the point where the glue lets go. Handy for dis-assembly, and rather dramatic with a chello.