That question has come up  too infrequently for me to become an authority, but I still need to know a lot about it. I’m not a woodworker, but I am a homeowner with fences, chairs, stairs, decks, railings, cabinets and retaining walls. Each different wood lives in different environments ranging from indoor cozy to outdoor assault. Some wood gets constant human contact; we may even eat with it. Other wood is out of sight. How does the average homeowner care for all these woods without becoming a fibrous scholar?
I was unable to answer that question to my own satisfaction, so I decided to once-and-for-all study what goes best on wood.
Walking the aisles of hardware stores is a rough place to start. It can be overwhelming. Interior or exterior? Are you penetrating or coating? Paint? Stain? Oil? Teak? Tung? Varnish? Shellac? Lacquer? Water or oil-based, or will it be beeswax?
I started with a notebook and something that has been bugging me for years. What goes best on redwood deck railings? When guests lean on my railings with their white cotton long-sleeve shirts and slide to the left, will my railing stain rub off on their shirts? (That happened!) I tried exterior spar polyurethane (plastic in liquid form with UV protection) for years, but it required annual sanding and reapplication to keep it sharp and spiffy.
I turned to internet research. Instead of Googling “What’s best for blah blah,” I flipped to Reddit and subscribed to their woodworking group, where real humans hang around and discuss favorite topics. “Hey, guys, novice here. What’s the best finish for deck railing to bring out the grain without the pain?”
As usual helpful replies came back almost immediately. A few said to live with the pain and polyurethane. Others said to paint and forget it. Then one guy suggested I try Penofin.
This was not a familiar name. My research began. Penofin is a product name, a penetrating finish if you will, based on Brazilian rosewood oil mixed with solvents, binders, resins, mildewcide, and other pigments. That fits a broadened definition of varnish – oil, resin, solvent. No trees are cut to make Penofin; they use only the seeds.
I couldn’t find it around these parts. Had to Prime it in. While waiting, I sanded my railings down to bare wood and washed them. When the gallon arrived and the lid came off, the sun rose behind me, and I could see my reflection in the oily gold. I was smiling.
With a new nylon brush, I made long liberal one-way strokes. My exhausted redwood sighed and opened up under the brush’s gentle massage. The rosewood oil spilled from the brush tips into open fibers. I left a trail of sunshine. Once the oil was inside, Penofin’s binders closed the door to the outside world with a nice hard UV-fightin’ finish. It’s been two months. Water still beads. Love it.
About oil, you can use it straight. When you add resins for protection or color, which need a solvent to keep them viscous, you have varnish.
Tung oil, linseed oil, and teak oil are popular treatments for exterior and interior wood. Tung comes from tung-tree nuts. It is waterproof and non-toxic. You can wipe your salad bowls with it. Boat owners likely have a can lying around. It fights back the sun. However, boat owners may also have a can of teak oil because it is great for UV protection. I am now using teak oil on the seats of my outdoor benches.
Teak oil is not made of teak, just like motor oil isn’t made from motors. It’s usually linseed oil, varnish, and mineral spirits. Danish oil, for interior use, has varnish in it that hardens inside the wood, not on top of the wood. That describes what the Penofin did on my railings. Perhaps I will nickname it as an exterior Danish oil.
What about wood coatings? Do you use varnish, lacquer, polyurethane, or spar. Spar belongs outside, and people have their preferences on the other three as a protective cover for fine wood. Varnish is oil, resin, and solvent, we know; lacquer is nitrocellulose and a solvent; cellulous comes from plant walls and vegetable fibers. Lacquer is most durable, favored, and sprays on nicely.
About resin, plants make it for protection around injuries, like viscous scabs. It’s then added to varnish to help protect the treated wood, and sometime enhance it. Hashish is a resin. So is shellac. It comes from the secretions of the female lac bug. The resinous insect secretions collect on tree limbs. They are chipped off in flakes and sold in bags to woodworkers who mix them with a solvent to create shellac. Shellac slipped out of vogue after the World War II invention of polyurethane, but people still use shellac to coat metal hinges, clamps, tools, and children’s toys. It’s popular in nail polish.
Chad, my son-in-law, who is undergoing chemo until September but is still on the move, came by my house the other day. “Here you go. I have a project for you.” We lifted a large slab of redwood from his truck bed. “You say you’re studying wood finishes. Make me a coffee table. I can’t do it right now. I have cancer.”

Steve Gibbs is a retired Benicia High School teacher who has written a column for The Herald since 1985.

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