I'm about to start assembling my first project of expensive veneer
plywood, which happens to be SWMBO's Christmas present. I don't skydive
so I have to get my thrills somehow.
Anyway, what about sanding?
Everything I've built so far has either been inexpensive Borg veneer or
wood at least a dozen sanding mistakes thick. At roughtly 4x the
price/sheet, plus time to reorder, I'm nervous.
I've been careful and managed to avoid any expensive mistakes *knocks
wood* How do I sand this stuff?
I plan to hand sand. Start at 120 or 150? 180? Sand to 220? Don't
sand at all?
You have to be very careful when sanding veneer with any type of power tool.
Usually the veneer is only a 32nd thick so you can go through it very
easily. When sanding, you are removing the scratches that were made by the
previous grit of sandpaper. I would sand by hand, start with 100 or 110
and go to 150. You may want to go to 180 but not 220. This will just start
to polish the surface and will make finishing more difficult.
Use a padded sanding block when you sand, with a cork bottom or a folded
paper towel even between the block and the sandpaper.
fancy veneer ply is usually sanded at the factory, so you can start
pretty fine. the coarsest I'll usually go on it is 120, and not too
much of that.
the exception to the rule about not sanding too fine is wet sanding
with oil. then you can go as fine as you want. sanding to 600 grit
with watco leaves a gorgeous surface.
I would do this on the lacquer top coat for to get nice consistent scratches
on the sruface to increase sheen, but not on the wood surface itself. If
you spray anything on a surface sanded this fine, the finish will simply
bead off. It will not adhere.
Unlikely. Many finishes incorporate wetting agents or are otherwise
formulated to deal with surface tension issues. I've sprayed shellac,
lacquer, varnish, oil-based poly and water-based urethanes on surfaces
sanded to 600 grit without any application problems or long-term adhesion
Well... first off, always ask yourself what you are sanding for. It is not
necessary to sand just because it's wood. Think about it for a second. You
sand to flatten surfaces. You may have to flatten large deviations in the
surface and for that you'd use coarser papers to take it down quicker.
But... that's the only reason you use coarser papers - to take it down
*faster*. After that you're stuck working your way up through lesser grits
until you get all of those nasty sanding scratches out. If however, you
don't have major deviations you don't use coarser grits - you use much finer
grits or even no sandpaper at all. You're only sanding to take out minor
imperfections. It's conceivable that you could simply need to clean up a
piece and find that steel wool or scotch pads are all you need. Start fine
and if it's not enough then move up a bit. Remember, you could do it all
with fine papers - even taking out the scratches from 80 grit paper, it just
takes longer. So, after all that, the message is look at what you're
working with. If it doesn't need a lot of sanding then don't sand the hell
out of it. Again - why are you sanding?
Nah - it's only money man.
So - why? What is either magical about 120, or what is wrong with your
piece that requires 120? If you can answer those questions, then go ahead
and use it... sparingly. If you can't answer those questions, then start at
180. Does it do all you need? Then quit. You should hate sanding anyway,
so it should be a good feeling to be able to quit. I think it even says
that in the Bible...
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