Paint over stained wood: yes, says Sherwin-Williams, with light sanding, deglossing and a primer, and it warns about stain bleeding through; Zinsser makes primers it says grip varnish without sanding. Stain over paint is another matter: no maker we read says its gel stain goes over paint. The closest is Varathane, whose gel stain data sheet gives a route for wood with an existing topcoat.
Painting over stained wood
Sherwin-Williams’ Stain FAQ answers “Can you paint over stained wood?” with yes, warns of the risk of “the stain bleeding through the paint,” and names light sanding and deglossing. Over a water-based stain it says to use a water-based latex primer first. Over an oil-based stain, it says to wash with a trisodium phosphate (TSP) and water mix, let it dry, then use a water-based bonding primer.
Zinsser’s B-I-N data sheet says not to use TSP as a cleaner before its own shellac primer. That is a different product from Sherwin-Williams’ route, so we’d follow the cleaning line of the primer you actually buy.
Painting over varnish or gloss
| Product | What it says | Prep it names |
|---|---|---|
| Zinsser Bulls Eye 1-2-3 | Adhesion to “enamel paints and varnishes” | “without sanding or deglossing” |
| Zinsser Cover Stain | Adhesion to “enamel paints and varnishes” | “without the need for sanding or de-glossing” |
| Zinsser B-I-N Shellac | “Excellent adhesion to glossy surfaces” | “without scuff sanding”; no TSP |
| Sherwin-Williams Extreme Bond | Names “Varnished Woodwork” | Sand or dull glossy, very hard surfaces with an abrasive cleaner |
| Benjamin Moore Advance | Paint, not primer | “Sand glossy alkyds before applying Advance” |
| Sherwin-Williams Emerald Urethane Trim Enamel | Paint, not primer | “Glossy surfaces should be sanded dull.” |
From each product’s data sheet. Zinsser’s 2017 comparison chart rates B-I-N, Bulls Eye 1-2-3 and Cover Stain “E” (excellent) on glossy paints and clear finishes; for tannin bleed it rates B-I-N and Cover Stain “E” and Bulls Eye 1-2-3 “G” (good).
Krud Kutter Gloss-Off is a liquid deglosser. Its page says it “Cleans and deglosses without sanding,” for “all paints, varnish, lacquer, and polyurethane,” and can be coated over any time after 10 minutes. Its data sheet lists it as non-flammable.
Old paint
Sherwin-Williams’ Paint FAQ says latex can go over oil-based paint, but “it is vital that the surface be properly prepared.”
EPA says that if your home was built before 1978, it is more likely to have lead-based paint. If you sand or scrape old paint yourself, EPA says to use its lead-safe work practices, and not to attempt to remove lead-based paint yourself. See epa.gov/lead.
Stain over paint
No maker we read says its gel stain goes over paint. General Finishes blocked our requests, so it isn’t here. What the makers we read do say is about staining over an existing clear finish or a factory-coated door:
| Product | What it says | Prep it names |
|---|---|---|
| Varathane Premium Gel Stain | Data sheet: “Finished Wood/Wood with Existing Topcoat” | “Lightly sand previous finish to improve adhesion”; dry times on finished wood “may take up to 24 hours”; test on a hidden spot |
| Varathane Total Control Gel Stain | “works best on factory-coated fiberglass and metal doors” | Lightly sand the previous finish with 220 grit; not directly over ferrous metal; not for floors, decks or siding |
| Minwax PolyShades | Over a polyurethane finish, “you can change the color without stripping it off” | See Minwax’s article |
| Minwax Gel Stain | “wood, plywood, veneer, fiberglass, metal and molded fiberboard” | None given; it doesn’t name paint or an existing finish |
From each product’s data sheet or page. Rust-Oleum’s own gel stain blog says to “Use sandpaper or a stripper to remove any existing coatings,” while the Varathane Premium data sheet gives the light-sand route for wood with a topcoat; we’d follow the data sheet.
Minwax’s Gel Stain label warns that rags used with it “may spontaneously catch fire,” calls it “COMBUSTIBLE,” and says “VAPOR HARMFUL. Use only with adequate ventilation.”