The schedule comes from the can
| Product | Coats | Recoat | Between coats | Use |
|---|---|---|---|---|
| Minwax Fast-Drying Polyurethane (oil) | 2–3 | 4–6 h | #220 paper | Light use after 24 h |
| Minwax Water-Based Oil-Modified Polyurethane | Not stated | 2 h | Not stated | Light use after 24 h |
| Minwax Wipe-On Poly (oil) | 2–3 | 2–3 h | #220 or fine steel wool | Normal use after 24 h |
| General Finishes Arm-R-Seal (oil) | 3–4 | 24+ h | Not stated in the data sheet | Cure 30 days |
| General Finishes High Performance (water) | 3–4 | 2 h | 220–320 foam pad | Cure 21 days |
From Minwax's product guide and General Finishes' data sheets; GF figures at 70°F and 50% humidity. Minwax notes that humidity, cold and thick coats all lengthen drying.
Applying it
Coat by coat
Prepare the surface
Sand to the finish maker's grit — Arm-R-Seal's data sheet says no finer than 220 — and remove all dust. Over stain, wait the stain maker's time first; see how to stain wood.
Choose the applicator the maker names
A brush for brush-on polyurethane — Minwax uses natural bristle for its oil-based spar urethane and synthetic for the water-based one; a lint-free cloth for Wipe-On Poly; a rag or, on flat surfaces, a foam brush for Arm-R-Seal.
Apply a thin coat
Along the grain, keeping a wet edge. Thin coats dry as the maker says; thick ones dry slower, Minwax notes, and General Finishes warns that its thin Arm-R-Seal is easy to over-apply.
Let it dry for the recoat time
Not the touch time. In the table, that is 2 hours for the water-based products and 4 to 24 hours for the oil-based ones.
Sand lightly between coats
Minwax uses #220 paper to remove dust nibs and, it says, to improve the next coat's adhesion; General Finishes uses a 220–320 foam pad on High Performance. Sand only enough to dull and smooth the surface, and never through to the stain.
Remove the dust and repeat
Minwax's test for enough coats: in bright, direct light, no dry spots should show.
After the last coat, the piece is ready for light use before it is cured: Minwax gives 24 hours before light use for its polyurethanes, while General Finishes gives 30 days for its oil-based Arm-R-Seal to cure and 21 days for its water-based High Performance. Treat the surface gently until the cure time has passed. The difference between these milestones is explained in polyurethane.
Removing it, or painting over it
- To get polyurethane off, see stripping wood — and refinishing furniture first, because a sound finish can often be recoated instead.
- To paint over it, the paint and primer makers set the preparation: Benjamin Moore says to sand glossy alkyd surfaces before its ADVANCE paint, and Zinsser says its B-I-N Advanced primer adheres to glossy varnishes without sanding. Test adhesion first; see paint and primers.
Safety— Oil-based polyurethane and rags
NFPA warns that rags wet with oil-based finishes heat as they dry and can ignite; General Finishes says to put Arm-R-Seal rags and brushes in a fireproof container. The other makers' and NFPA's procedures are compared in finishing techniques.
Applying polyurethane
- The product's own coats, recoat time and between-coat abrasive
- The applicator its maker names
- Thin coats, along the grain, with a wet edge
- The recoat time kept, not just the touch time
- Light sanding and dust removal between coats
- Gentle use until the maker's cure time has passed
Sources
Coats, recoat times and between-coat abrasives are each maker's for its own product, at the conditions it gives; 'not stated' means the document reviewed gives no figure. The schedule of the product in hand overrides anything here.
- 1.
Minwax Product Guide. Minwax.
Used for: Fast-Drying Polyurethane: 2–3 coats, recoat after 4–6 h, 24 h before light use, #220 between coats to remove dust nibs and improve adhesion, more coats if dry spots show in bright light, slower drying in humidity, cold or thick coats; Water-Based Oil-Modified Polyurethane: recoat after 2 h, 24 h before light use; Wipe-On Poly: 2–3 coats with a lint-free cloth, 2–3 h between, #220 or fine steel wool between coats, 24 h before normal use; brush types for oil- and water-based spar urethanes; no sanding needed between coats of brushing lacquer.
- 2.
Technical Data Sheet, Arm-R-Seal. General Finishes, 2020.
Used for: Arm-R-Seal: thin coats with a rag or cloth, a foam brush on flat surfaces, spraying not recommended; 3–4 coats; 24+ h recoat; 30-day cure at 70°F and 50% humidity; rags and brushes in a fireproof container.
- 3.
Technical Data Sheet, High Performance Topcoat. General Finishes, 2019.
Used for: High Performance: synthetic or foam brush; 3–4 coats; 2 h recoat; fine 220–320 foam pad between coats; 21-day cure at 70°F and 50% humidity.
- 4.
Technical Data Sheet, ADVANCE Waterborne Interior Alkyd Satin 792. Benjamin Moore.
Used for: Glossy alkyd surfaces sanded before painting over them.
- 5.
Technical Data BIN-01, B-I-N Advanced Synthetic Shellac Primer. Rust-Oleum (Zinsser).
Used for: B-I-N Advanced described by its maker as adhering to glossy varnishes without sanding or de-glossing.
- 6.
Safety with Oily Rags (safety tip sheet). National Fire Protection Association, 2019.
Used for: Rags wet with oil-based finishes heating as they dry.
About this guide
Written by BenchRoot Editorial. How BenchRoot sources, checks and corrects its pages is set out in the Editorial Policy. If something here is wrong or unclear, the contact page explains how to tell us.