Types of Finishes

There are two major categories of finishes: penetrating oils and films.

Penetrating oils …uhhh…penetrate the wood fibers, get into the cells and then cure to a hard material. It’s hard to sand penetrating oils off a piece of wood for this reason. These finishes often give wood the gorgeous amber pop you want in a project. Boiled linseed oil and hard-wax oils are examples of this finish. I have used Tried and True Original, Odie’s and Rubio Monocoat to great effect. Osmo requires some finesse to apply, but it does work. Penetrating oils give some protection, but make up for this by often being easy to repair.

Film finishes drop a film of binder on the top of your wood project. The finish does not penetrate the top layer of wood. Polyurethanes (both oil- and water-based), lacquer, epoxy and shellac are examples of film finishes. Film finishes are great choices for hard wearing surfaces, such as table tops, but don’t often don’t repair very well. Two exceptions: shellac and tung oil both get high reparability marks.

The Parts of a Finish: Resins, Pigments, Solvents

Resins are the dissolved solids in a finish that will eventually coat the workpiece after the finish cures. Pigments color the finish and solvents dissolve the solids. Most finishes bought at the big box stores need to be thinned with the appropriate solvent in order to perform at its peak. Woodworkers can introduce pigments to certain finishes - such as lacquer - to create spectacular custom stains and looks. These are Advanced Finishing techniques. There’s lots learn in these advanced topics. A great resource is Bob Flexner’s **Understanding Wood Finishes.**

Some Rules of Thumb (With Gloves On!)

No matter which finish I use, I always follow these rules of thumb:

1. For lacquers, polys and shellacs, thin the finish to a ratio of 1 part solvent to 3 parts finish. Water based finishes I thin only about 10%. I use mason jars with graduation markings to rough out my proportions. All wood finishes at the big box store are too thick for easy application with brush, rag or spray gun. So I pour some finish into a pint-sized mason jar and top it off with the solvent. The result is a finish which needs more coats, but applies without brush marks, drips, etc. associated with thicker finishes.
2. Double check my application process using a finishing reference. And that reference is Bob Flexner’s Finishing 101.
3. Wear gloves. Over the years I’ve developed some mild allergies to the contents of finishes – a case of one too many applications without gloves. I also remove any jewelry from my hands – my rings tend to exacerbate the issue.
4. Test it on a piece of scrap sanded to a comparable grit. Because if you don’t, your finish will be a surprise!
5. When in doubt, Odie’s Oil. This is a go-to finish for many, many people for good reason. It works.

My Go-To Finishes and Why They Should Be Yours Too

I have three go-to finishes for different applications.

For anything which will contact food or mouths, I soak the workpiece in mineral oil. I use wood butter to maintain these projects.