Thursday, May 26, 2016

A Simple, General Purpose Woodworking Finish

Finishing is a complex subject which can seem a tad bewildering to beginning woodworkers. There are a multitude of products on the market, and numerous special finishes for particular applications or visual effects. The following, however, is a good general purpose finish that should give good results for most indoor projects regardless of the type of wood used. It doesn't require any special tools or knowledge and the supplies are available at any hardware store.

Supplies Needed

  • Several Lint-Free Rags - Scraps from a worn-out t-shirt are ideal. Heavy-duty paper towels will also work.
  • Cotton Swabs or Small Cheap Brush - For getting into tight spaces.
  • Disposable Rubber Gloves - Unless you don't mind staining your hands brown.
  • Oil Based Stain - All of the brands give similar results. The shade is a matter of personal preference; when in doubt go with any of the "medium" brown colors.
  • Premixed Shellac - I use Zinser brand, which is widely sold here in the States.
  • Denatured Alcohol - For thinning and cleaning up after the Shellac. This is just high-concentration rubbing alcohol.
It is often a good idea to sand and finish a scrap first to see what a finish will look like when it's done. If you write notes on the back of the scrap you can save it and start building a "library" to help remember what different finishes look like on different kinds of wood. If you're satisfied then go ahead and finish your project.

Step-by-Step

  1. Sand everything to 180-grit. Try to sand hard-to reach spots before you glue together your project.
  2. Thin shellac about half-and-half with alcohol to make a sanding sealer. Rub this over your whole project and allow it to dry for at least half an hour. The sealer will fill in the pores of the wood keep the stain from streaking--a particular problem with pines and maples.
  3. Lightly hand-sand with 220-grit.
  4. Stir up your stain and wipe it onto your project with a rag. You can put it on fairly thick. Use cotton swabs or a brush to push stain into corners and small details.
  5. Give the stain about 15 minutes to soak in then wipe off the excess with a clean rag.
  6. Optional: If the stain is uneven or you missed some spots, repeat the last two steps for a second coat.
  7. Let the stain dry completely. Depending on how dry the air is, this can take up to 18 hours.
  8. Use a clean rag to wipe on two coats of premixed shellac, waiting at least 20 minutes between coats.
That's it, you should now have a beautiful finish that looks professional and shows off the grain of your wood. With basic dusting and occasional polishing with a good (non silicone) paste wax, the piece should last for generations.

Safety Concerns

Neither shellac nor wood stain is particularly nasty stuff--certainly not compared to most modern lacquer or epoxy finishes. It's still a good idea to do your work in a well ventilated area, however. The biggest safety concern is properly disposing of the oily rags. Stain-soaked rags are highly flammable and can spontaneously combust if they get too warm before they are totally dry. It is not safe to through wet oily rags directly in the trash. Back when I had a wood stove in my shop I used to just burn them there. Nowadays I hang them on an old coat hanger until they are dry enough to throw away.

A Variation for "High Abuse" Applications

Shellac is a good general purpose finish, besides being economical and environmentally friendly. Unfortunately it isn't tough enough for surfaces like kitchen tables that see heavy daily use, including spilled liquids and coffee rings. For these sorts of surfaces you can follow the steps above, but substitute wipe on Polyurethane for the Shellac, which will give you a thicker, more liquid resistant top coat. Minwax makes a wipe-on Polyurethane that I've used several times with good results. You can also make your own by thinning regular polyurethane with mineral spirits.

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