Hey Stuart,
I’m just guessing here, based on a similar experience of my own, but I can’t help but to notice the piece of black sandpaper in your photo. I also can’t help but to notice that those pieces of paper have some bare spots showing.
I don’t mean to insult you, but is it possible that you used a black sandpaper that LOOKED like wet-or-dry paper, but which was really not suited for wet work? I only ask because I did the same thing some years back, and made a mess that took a while to clean up.
3M (and maybe some other companies as well) makes a black paper, that looks like wet-or-dry paper, but it’s really only for dry sanding. If you sand wood wet with that kind of sandpaper, it will leave a residue of black glue and grit on the wood. It can also leave tiny little pieces of grit embedded in the wood.
A mild blackish residue in the low spots is probably no big deal. As the other guys said, it will probably disappear under the stain. If you wanted a mildly aged finish, then that gets you headed in that direction anyway. (Maybe the acetone will help.)
BUT if the paper left little pieces of grit in the wood, that can become a big deal. If the light hits the stock just right, they will sparkle just like a piece of glitter on a high school cheerleader’s face. The only way I know to get them out is to put on a magnification visor or at least a strong pair of reading glasses, turn off the lights, then go over the stock closely and very carefully with a flashlight held at an angle (so as to reflect the light). If you do that and can see grit sparkling back at you, then you can pick it out, one grain at a time, with a very sharp needle.
I would also recommend you lay the stock down (on the kitchen counter for example), so that you can look at it very closely without holding it. Even the slight movement of your hands is enough to keep you from seeing the sparkle easily, but if you lay it down so that it is still, and then move the light over it, those little guys sparkle and shine like they are proud of themselves.
Might I also, while I’m at it, suggest that you do this while the wife and kids, and maybe dog as well, are either out of the house or at least well out of the way? Maybe some calming music in the background?
Would grit like this show up in a stock out in the bright sun? I don’t know. But I would think that if you want it out, you have to get it out before you apply any varnish, etc. You cannot pick it out once you have glued it in! In my experience, I noticed it after I had applied stain. The contrast against the dark stain made it easy to see the sparkle, but it was a real bear to get it out and I basically had to rework the entire piece with scrapers so as to deal with the little picked marks in the wood, etc.
If, after this experience, you still like finishing by sanding and want to try wet sanding some more, then you might want to try 3M Wetordry ™ paper. It is available at auto supply stores, where it is sold for working on autobody repair. It is available in grits from 220 or so up through 1200. I use it quite a lot on metal, and it’s great stuff.
By the way, just before posting this I ran some tests with some old scraps of cheap black paper that I had from back when, and compared it to a test with some of the Wetordry ™ stuff in 220 and 400 grits. I tested both kinds of paper, first dry and then wet, on a scraps of curly red maple. It was just as I remembered. Black smudges and grit in the wood with the cheap stuff. No residue and no grit with the Wetordry ™ stuff.
Whet
PS: nice work on the beavertails!
