Hey guys, I'm currently trying to wetsand the clearcoat of a guitar I'm building and I'm running into some problems I'm not sure how best to solve. I don't have a sanding block, so I tried using a water bottle cap instead. I started with 600 grit, letting it soak a bit first, but when I'm sanding no matter how much water or how little I use I'm still getting buildup at the edges of the paper, leaving some nasty black marks on the guitar that I have to rub out with a fresh piece. What am I doing wrong? Should I just go find some scrap block of wood to use instead? I still don't understand why gunk is building up even though Im dipping the paper back in water every ten seconds or so to try and clean it. Thanks for any help.
Use a sponge or something as backing, and make sure you're working in concentric circles if you're trying to smooth a large area.
alright thanks man, I'll go try that
Wow that works much better, thanks again
Add a little soap to it as well (the water). This will help prevent friction when sanding as well.
ok I'll do that as well, thanks
I use mineral spirits instead of water but not for oil based polyurethanes