I've got a guitar with a hard, glossy black finish (likely urethane), and I can't say I'm really a fan. Would I be able to spray a satin clearcoat over it? I think it would be neat for most of the guitar to be satin but have the gloss come through in more worn areas. Good or bad idea?
Quote by LeviMan_2001
You can just lightly wetsand your current finish to achieve a satin look. Probably 1000 grit or 2000

this.....you can also use scotch brites
If you want to dull the sheen, then just wetsand it with a really high grit sandpaper(as was already suggested).

If you want an actual satin finish, then scuff sand it with 320 grit sandpaper an spray on a satin finish.
You can also use 0000 steel wool. I use that to kill the gloss on the back of a neck for faster sliding. And yes, I suppose you could top it with a touch of satin clear, but it would be more durable to merely sand the current finish. Plus, you could easily buff it back out later if you were so inclined.
I just want to add that if you do wetsand, you should avoid getting water on bare wood anywhere on the guitar. This includes any hole were drilled into the body. If water gets in the wood, it will expand and crack the finish. Some people use super glue and a little brush to seal exposed wood, and some people use a mixture of mineral oil and mineral spirits instead of water(I haven't done that, but supposedly the oil/spirits will not expand the wood).