Friday, January 29, 2010

The Finish Line

When I'm in "the zone", it can be difficult to resist the desire to glue up a project before I add finish to inside pieces of a drawer or cabinet.

But you do yourself a favor if you finish first, assemble second. That's because trying to achieve a flat, brushed- or ragged-on finish when you're dealing with inside corners is next to impossible.

I fixed the drawer on my sawbuck table but, tempted as I was to glue it up, decided to first conduct a comparison study of different finishes on a practice piece to see which looks best.

The sawbuck table is made from curly cherry, a wood that's tricky to plane and tricky to finish, at least in my world.

My normal finishes of choice are shellac, Watco wipe-on poly, and boiled linseed oil (BLO). I never stray too far from them because I'm not an enthusiastic finisher and prefer to get the process done and dusted.

I consulted with friends and researched a few ideas and chose the following to try on a test piece, which was sanded to either 220 or 320 grit (I can't remember).

1. 2 coats of garnet shellac; 8 coats of blonde shellac; rubbed out with 0000 steel wool.

2. 1 coat of tung oil, thinned 30%, and dried for 24 hours; 2 coats of 100% tung oil, with 24 hours drying time in between.

3. 1 light coat of BLO, dried for 24 hours, then lightly sanded with 320 grit paper; 1 coat of garnet shellac; 6 coats of blonde shellac; rubbed out with 0000 steel wool.

4. 1 coat of BLO, dried for 24 hours, then lightly sanded with 320 grit paper; 1 coat of garnet shellac; 6 coats of blonde shellac; 1 coat of Watco wipe-on poly; rubbed out with 0000 steel wool; 1 coat of dark paste wax, rubbed out with a soft cloth.

Two woodworking buddies visited my shop last night and I asked their opinions. Neither one saw a difference between #3 and #4 (I thought #4 looked a little darker). Neither one liked the tung oil (nor did I). Both preferred the straight shellac (as did I).

#3 and #4 popped the figure the most and were darkest, although they did look a bit blotchy (maybe sanding to a higher grit would fix this?). I also thought they looked a little too shiny for a rustic piece, but they would look terrific on fine piece of furniture.

The tung oil looked dull and uninteresting and did not bring out the figure as I thought it would.

The shellac looked most natural and had a soft, buffed sheen. The figure did not pop as much (but there was not as much figure on the end of the board), however, it did not look at all blotchy.

I'm no finishing expert, so in the hands of someone else, all four finishes might look fabulous. But I've decided to stick with shellac. For this experiment, I applied more layers of shellac than I had ever done before, and I can say without hesitation, that the more layers, the better-looking the finish. I usually stop at four layers, but applied 10 to this sample. The result is beautiful.

Recently, there was discussion on the SAPFM forum regarding BLO and shellac. Two points that grabbed my attention: BLO will turn black over time, and shellac might peel if poly is applied on top of it.

One thing's for sure—if you're going to spend a lot of time building a project, it's worth it to invest the time in researching the best finish. Even if you end up using the same old standby.