I noticed a thread today where a builder was worried about some scratches on the plate he planned to paint. In that particular thread, it sounded like the scratches were fine enough that the hammertone paint would almost certainly fill the voids.
After reading the thread, I did realize that some of the beginners might not know a good way to fill scratches/dings on the plate before painting (especially with paint with any gloss since it'll show pretty fine scratches).
The best filler for scratches in metal that's generally available is Bondo Spot Glazing Putty. You can buy small tubes of it at most auto parts stores and is made to fill scratches and dings in auto bodies in preparation for painting.
It's a lacquer based filler and it's main advantage over most any other type of filler is it's ability to fill very shallow voids and not come out as you sand it flush. Just be sure and let it dry overnight before sanding (probably much less for most voids you'd encounter on your top plate but if you try and sand it before it's dry through and through, it will rub out and you'll be back at square one).
Sand the dried Bondo putty with aluminum oxide 220 grit then aluminum oxide 320 grit sandpaper and prime (the putty is dark red and difficult to cover so spot prime, lightly sand and re prime until the the fill is invisible.
For the alder that Bottlehead makes their bases from, an excellent filler is Elmer's Carpenter's Wood Filler. It comes in several shades and Golden Oak works very well with alder. If you happen to be working with something like maple, the Natural color is best.
Elmer's Wood filler is stainable and while nothing will look natural if the fill is too large and you can't "fitch" the woodgrain (using dry brush techniques with the appropriate stain or ink to imitate the wood grain), the color should match pretty well after you've stained and finished the repair.
Once again, it's important to be patient and give the fill(s) 24 hours to fully dry before sanding. It will look dry before that but the filler will be rubbery until totally dry and it will take twice as much sanding to level the surface. When you have to struggle sanding a fill, your always in danger of "cupping" the wood around it making the problem worse.
Once the fill is flush, be sure and lightly sand the entire side (with the grain) to even out the pores of the wood and get rid of any crossgraining from the sanding (causes crosshatching scratches to show up after staining.
I hope this helps some of you guys.
