Oil stain is the go-to finish for furniture, shelves, and other woodworking DIY pieces.
This article covers:
・Why oil stain is the recommended finish for DIY
・What oil stain is
・How to apply Watco Oil
using “Watco Oil” — a classic oil stain — as the example.
The application section also covers a fine-finish technique using wet/dry sandpaper, and the question of “can you topcoat Watco Oil with varnish?”
◆ Related: water-based stain finish — see this article (Japanese version available; English version forthcoming).
Why Oil Stain Is the DIY Finish I Recommend
One-line summary: oil stain “levels up your build, easily and enjoyably“.
・Easy (uneven application is unlikely)
・Beautiful texture, vintage feel
I was the same — most DIY beginners don’t even know what oil stain is. But applying oil stain is the easiest way to bring out a piece’s natural-wood texture and a vintage look.
If you’ve been avoiding finishing because “painting is fussy”, oil stain is exactly the place to start.
For me personally, Watco Oil is what made me fall in love with finishing in the first place.
Caveat — about oil stain odor
Oil stain contains organic solvents — you’ll need to ventilate during application and drying.
If the smell bothers you, or you live in a one-room apartment with no separate space to dry the piece, water-based stain is a better fit. (Most water-based stains then need a topcoat — varnish or wax — for surface protection.)
What Makes Oil Stain Special
“Penetrating” finish — preserves the grain
Paint and traditional lacquer (urushi) form a film on top of the wood (“film-forming” finishes), which adds color but covers the grain. Stain soaks into the wood (“penetrating” finishes).
With penetrating stain, the grain is preserved — the wood texture stays intact.
Wood protection
Beyond color, finishes also protect the wood from wear/aging.
Penetrating finishes don’t protect as strongly as film-forming finishes (paint, varnish, etc.).
That doesn’t mean oil stains have no protection. Watco Oil is sold as an “oil finish”, meaning it functions as a finish coat with real wood-protective properties.
That said, its protection is below what you’d get from varnish or paint. If you really need maximum protection, topcoat Watco Oil with varnish.
Personally I usually leave it at Watco Oil with no varnish.
Oil stain vs. water-based stain — and “oil finish”
What’s the difference between oil stain and water-based stain?
→ It’s the solvent. Oil stain uses paint thinner; water-based stain uses water.
Oil stain — solvent: paint thinner
Water-based stain — solvent: water
As above, Watco Oil is one type of oil stain that’s also branded as “oil finish” — meaning “you can use it as a finish coat”.
So is the rule “oil stain doesn’t need a topcoat, water-based stain always does”? Not exactly — some oil stains do need a topcoat, and some water-based stains include varnish ingredients that make a separate topcoat unnecessary.
→ Confusing in the abstract, but the package will tell you. Look for instructions like “topcoat with varnish”.
・How to tell if your stain needs a topcoat — read the package warnings.
How to Apply Watco Oil
Core workflow: brush it on, wipe off the excess with a cloth.
Oil stain is hard to clean off your skin, so wear rubber or vinyl gloves.
What You Need
<Required>
・Brush
・Cloth (rag)
・Sandpaper (#240–#400)
<Nice to have>
・Gloves (rubber, polyethylene — anything paint-impermeable)
・Wet/dry sandpaper (#400+) — only if you want a particularly clean finish
Wet/dry sandpaper is used between coats for an extra-clean result. Optional.
① Sand the wood (#240–400)
Prep the surface with sandpaper.
“Is sanding before staining required?”
→ Don’t be obsessive about it, but sanding does help the stain absorb evenly.
Plus, if you don’t sand, surface roughness will catch a Swiffer / cleaning rag once the piece is in use.
#240–400 sandpaper, sanded with the grain.
② Brush on the stain
Brush on a generous amount of oil stain.
③ Wait 15–30 min, then wipe with a cloth
Let the stain soak into the wood for 15–30 min.
Then wipe off any unabsorbed stain with a clean cloth.
※ Two coats are recommended, but for DIY a single coat is also fine — in that case, skip to step ⑥.
④ Dry for ~1 hour
Let dry for about an hour before the second coat.
⑤ Brush on second coat (+ optional wet-sand)
Apply a second coat to the entire surface.
Use less stain than the first coat.
<Optional wet-sand for extra-clean finish>
To eliminate raised grain and unevenness for a particularly clean finish: wet-sand (#400+) while the second coat is still wet on the surface.
⑥ Wipe off with cloth
Wipe the surface completely clean.
Sometimes oil that has soaked in seeps back to the surface an hour later — wipe it again if so.
⑦ Dry
Let it dry — done.
Watco’s instructions say “dry 24+ hours”, but the smell takes longer than 24 hours to fully fade. About 1 week to be totally odor-free.
⑧ Result: pine glue-laminated panel and SPF examples
The walkthrough above used pine glue-laminated panel; I did the exact same process on SPF lumber too. Same stain, different feel.
■ Watco Oil (Dark Walnut), two coats
1. Pine glue-laminated panel
2. SPF
[Bonus] Can you topcoat Watco Oil with varnish?
Bottom line: yes, no problem.
Watco Oil already provides reasonable protection, but for surfaces that need extra durability, you can apply varnish over the top.
That said — Watco Oil’s appeal is the natural feel it leaves on the wood, and varnish degrades that feel somewhat. (Personally, I usually skip the varnish.)
If you want some of the oil-finish feel preserved, picking matte varnish over gloss is a reasonable compromise.
Examples with varnish topcoat
Examples with water-based urethane varnish — clear gloss vs. clear matte.
Pine glue-laminated panel — Watco Oil + water-based varnish
Left = clear gloss, right = clear matte.
Watco Oil + related products:
Watco Oil:
Cloth rags:
Brush:
Polyethylene gloves (article uses rubber, but I use these often too):
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