No matter which finish you apply, smelly lacquers and polys or the waterborne stuff, you still have to sand it to smooth the grain. They all affect any loose fibers, leaving many of them sticking up and the wood's surface feeling like sandpaper.

For smoothing the PSL, Jeff suggested I use 400 grit 3M FreCut Gold, #216U. I like to try new things so I said OK.

As it turned out, this sandpaper is pretty great. Sometimes when I need to sand large, freshly sprayed surfaces, the only way to avoid clogging even the best stearate papers, I need to use an orbital sander. Hand sanding clogs the paper too quickly.

Not this stuff. It cut quickly and cleanly and nothing would stick to it. When given the choice between hand sanding or working in a cloud of dust from my orbital, I'll take the hand sanding every time!

One of the reasons I tried to get lots of finish on yesterday derives from the knowledge the more material on the wood, the less likely you will sand through it. If you cut through the lacquer, any new lacquer will re-raise the grain and you have to start over.

Edges are particularly vulnerable since most finishes, as they dry, shrink and pull away from the edges. This leaves them thin to start out with and any pressure applied to the sandpaper on the corners will definitely sand through.

To get the corners smooth AND avoid sanding down to bare wood, I let the stiffness of the sandpaper apply the pressure.

The real key to a good sanding job, as mentioned above, is to not sand through the finish. As long as the dust is white, you're doing good. If it starts to turn brown, you're going too far or you need to apply more finish before attempting the sanding stage.

Another thing - just looking at what you're doing isn't enough - you have to feel the surface to know when you've sanded it just right. When it feels smooth, move on to the next area. When you find a rough spot, just sand that.

In this picture of the door cabinet side, you can still see white dust in the wood pores after wiping down the surface. The plywood is affected the same as the solid wood faceframe.

Even though there are lots of techniques for really cleaning a surface prior to topcoating, my favorite is using compressed air to dislodge the embedded dust. You don't get it all, but any small bits left in the pores just melts into the finish during spraying.

There are other things I do before topcoating, to ensure a clean-looking job. Using the blowgun, I de-dust the section of the shop between the two windows, which feed the fan, and the fan itself. I try to get as much of the airborne dust headed out the exhaust fan so my shop stirrings don't kick up anything which will flaw the topcoat. I also thoroughly de-dust myself. Who needs a dandruff shampoo when you have compressed air? ;)

Finally, with the part sitting in the spray area and using the air-only trigger setting on the spray gun, I wipe my free hand over the whole surface to loosen any debris still clinging to the wood.

Of course, the proof is in the pudding and I'm really happy with the PSL. With 30% solids, it builds much faster than my regular lacquer and I'm inclined to call these "done".

Still, I put an extra coat on one of the drawer face backs just to see what it looks like. In the morning, after it's fully dry, if it doesn't end up looking too plastic, I'll go ahead and put two topcoats on everything for that added layer of protection. From what I can see now, it won't be necessary.

FYI, the PSL can be re-coated without sanding up to 24 hours after spraying. And each coat burns into the previous coat just like nitrocellulose lacquer, eliminating any possibility of witness lines showing should it get sanded through. Could be handy if anyone ever wants one of those piano finishes.

If you have any questions or comments about Mr. D's Walnut Wall Unit, please post them at the Info Exchange.

Jim Mattson