WWR: Finishing Myth #1

by Pappy October 3rd, 2007, Posted in: Woodworking


Woodworker’s Resource has a ten-part special report they release to newsletter subscribers, entitled “Finishing Myths: BUSTED!“.  Here’s myth #1:

Finishing Myth #1:

The higher grit of sandpaper you sand to the better the finish will
look.

If you were to leave the piece unfinished, a grit of 400 or higher
would “polish” the wood.  This would give the piece  a nice feel
and a gloss sheen.

However, if you use a film finish (varnish, shellac, lacquer, or
water base) you won’t be able to see or feel the difference.  What
does that mean?  It means you’re wasting your time if you sand past
220 grit if you plan on using a film finish.  I normally stop at
180 grit.

Myth #1: BUSTED!

For oil and oil/varnish blends (danish oil) I sand to 180 - 220
grit.  I then flood the wood with oil and let it sit on the wood
for a few minutes before wiping away the excess.  Let it cure
overnight and then go over the piece with 220 grit to remove any
dust nibs or other imperfections.  Remove the dust and then wet
sand the piece with 400 wet/dry sandpaper with the second coat of
oil.  This will give the piece a nice smooth feel and look, much
like the film finish described above. Just keep in mind that the oil
finish will not protect the wood like a film finish can because an
oil finish doesn’t build up on the surface of the wood.

I highly recommend you subscribe to the Woodworker’s Resource newsletter, and don’t forget to check out their video blog while you’re there.

First Project: Workshop Stool (Part 2)

by Pappy September 23rd, 2007, Posted in: Woodworking


When we last left off with the workshop stool project I’d completed the legs, crossbars, and seat support. That left the seat and finishing to be done before calling the project complete.

The oak I bought for the seat was too thin, only 3/4 inch. So the first order of business was to cut two matching 12 inch by 12 inch pieces and glue them up to achieve a thicker seat. The very first advice I got from every woodworking community online was that you can never have enough clamps. Apparently, I didn’t listen to this close enough, because I thought 2 clamps (all I have at the moment) would be enough to handle the glue job. They weren’t.

After taking care to choose which side I wanted visible, I doled out a liberal amount of Titebond wood glue, aligned the two pieces, and clamped them down on opposite corners. To start with, this left too much play and the top piece kept floating on the excess glue, and two clamps did not provide enough even pressure across the entire surface to force out the excess glue. Now, in a panic as it was too late to stop, I pulled the bench vise off and used it to clamp down a third corner, which did help enough for me to be able to keep the two pieces lined up right and squeeze out much of the excess. Then I covered the piece with a shop rag to keep it from getting marred and placed 20 pounds of cinder block on the 4th corner.

Sloppy, sloppy, sloppy, and unfortunately it showed in the results. The three clamped corners formed a nice tight seal, while the fourth left about a 1/16 inch gap, with the dried glue forming a sort of wedge between the pieces. I’d have included a picture, but my crap-o-matic $10 digital camera won’t capture that kind of detail no matter how well I light it or how close I get…

It then bears repeating: you can never have enough clamps. In hindsight I would have placed clamps on the corners, in the middle, plus a clamp over each of the edges to guarantee proper alignment.

“Red Four, this is Red Leader. You need more clamps.”

“Cap’n, I don’t think the dilithium crystals in the warp core matrix can handle the stress: we just don’t have enough clamps.”

Oh well, live and learn I guess. Next I used Minwax Wood Filler to fill the holes inside the gap where air pockets had been. Using a 1/2 inch round-over bit, the next task was to route all the edges of the seat to give it a nice smooth top that wouldn’t poke me in the arse. A full course of sanding, from 80 grit, 100, 150, and then 220 and the seat piece is finished.

Attaching the seat was an easy affair. A little alignment and 5 woodscrews later and construction is done.

E gads! It was right about this point that I realized I should have done all the stain and finish work prior to buttoning it all up. I was so concerned that I wouldn’t get all the angles lined up right I didn’t even think about the order of putting it all together. Fortunately, the stool design is open enough I can reach everything with a brush without too much trouble.

The finishing pattern was as follows: single coat of Minwax Golden Oak stain, one very thin coat Minwax Polyurethane High Gloss, no sanding between this and a second coat of polyurethane (see note below), very light sand with 380 grit, and a final coat of polyurethane. Although the Minwax guide recommends sanding polyurethane between each coat, I’ve read that with polyurethane it is very easy to sand through the first layer and into the stain beneath. If this happens, the only way to fix it is to sand off all the stain and finish and start over. Instead, it’s recommended to apply a thinner than normal first coat and to sand only after the second and successive coats.

Workshop stool - final coat of polyurethane dryingSo, while enjoying my morning coffee this morning and waiting for the second coat to dry, I came across an interesting tip I wish I’d known about a few hours earlier. Wood magazine has a special issue out this month called “215 Fixes for Common Woodworking Mistakes“, and on pages 110-111 they have an excellent article on grain fillers. I never knew such a thing existed. With open grained woods, such as oak, ash, mahogany, and walnut, it is impossible to get that glass-smooth surface with just stain and topcoat. Run your fingers across one of these woods and you’ll feel the pits created by open pores and channels in the wood fiber. Grain filler, a mixture of solvent with silica, is designed to level up these pits and give you a surface worth bragging about.

Although I came across this information too late to use it this time around, you better believe I’ll be trying it out the next time I work with oak.

Well the only thing left to do is nail the steel furniture feet onto the legs - close enough that for the purposes of the blog it’s all complete. Hindsight is a great teacher and I definitely learned more of what to do and what not to do. Thank you to everyone that gave their advice, sent me emails telling me I was doing it all wrong , and of course the authors of the million or so articles I’ve read in the last few weeks.

Stay tuned, cause Pappy’s gonna be back soon with another project and I’ll need lots of correction and ass-kicking by wiser and more experienced folks than I.

Count on it. :)