Shellac vs polyurethane
Shellac is far quicker between coats: Zinsser’s later coats recoat in about an hour, against 3–4 hours or more for oil-based polyurethane. Zinsser also says plainly that shellac is not as durable or scratch-resistant as polyurethane or floor finishes.
On using them together, Zinsser says Bulls Eye Shellac is not recommended under polyurethane and names its dewaxed SealCoat for sealing wood before a polyurethane topcoat.
Side by side
| Property | Shellac | Oil-based polyurethane |
|---|---|---|
| Touch-dry | Zinsser Bulls Eye Shellac: 10–15 min | General Finishes Arm-R-Seal: 12+ h |
| Recoat | Zinsser Bulls Eye Shellac: 0.33–1 hZinsser Bulls Eye SealCoat: 0.75–1 h | Minwax Fast-Drying Polyurethane: 3–4 hGeneral Finishes Arm-R-Seal: 24+ h |
| Ready for use | Not printed by the makers we read | Minwax Fast-Drying Polyurethane: 24 h (light use) |
| Full cure | Not printed by the makers we read | General Finishes Arm-R-Seal: 30 days |
| Coverage | Zinsser Bulls Eye Shellac: 400–600 sq ft per gallonZinsser Bulls Eye SealCoat: 400–600 sq ft per gallon | Minwax Fast-Drying Polyurethane: 125 sq ft per quartGeneral Finishes Arm-R-Seal: up to 500 sq ft per gallon |
| Thinning | Zinsser Bulls Eye Shellac: Denatured alcohol (premixed at a 3 lb cut; Zinsser recommends thinning)Zinsser Bulls Eye SealCoat: 1:1 with denatured alcohol as a pre-stain conditioner | General Finishes Arm-R-Seal: Mineral spirits |
| Makers say it is for | Zinsser Bulls Eye Shellac: furniture, cabinets, floors, toys | General Finishes Arm-R-Seal: furniture, cabinets |
| Makers say not for | Not printed by the makers we read | Not printed by the makers we read |
The products behind it
| Product | Touch-dry | Recoat | Use | Full cure | Coverage | Thinning and notes |
|---|---|---|---|---|---|---|
| Zinsser Bulls Eye Shellac One source: Rust-Oleum (Zinsser), the maker of that product | 10–15 min | 0.33–1 h | — | — | 400–600 sq ft per gallon | Thinning: Denatured alcohol (premixed at a 3 lb cut; Zinsser recommends thinning).Conditions: 70 °F; not above 85 % RH.First coat on bare wood: sand and recoat in about 20–30 minutes; later coats touch-dry in 10–15 minutes and recoat in about an hour. Not recommended under polyurethane. |
| Zinsser Bulls Eye SealCoat One source: Rust-Oleum (Zinsser), the maker of that product | — | 0.75–1 h | — | — | 400–600 sq ft per gallon | Thinning: 1:1 with denatured alcohol as a pre-stain conditioner.Dewaxed shellac sanding sealer, the one Zinsser names for sealing under polyurethane; sand after 45 minutes, recoat in under an hour. |
| Minwax Fast-Drying Polyurethane One source: Minwax (Sherwin-Williams), the maker of that product | — | 3–4 h | 24 hlight use | — | 125 sq ft per quart | Sand lightly with 220 grit between coats; 3 coats for most durability. |
| General Finishes Arm-R-Seal One source: General Finishes, the maker of that product | 12+ h | 24+ h | — | 30 days | up to 500 sq ft per gallon | Thinning: Mineral spirits.Conditions: 70 °F, 50 % RH.A thin oil-based topcoat GF says to apply in thin coats with a rag. |
Related
Work it out for your project
Times are the makers' own at the temperature and humidity they name, and several of them say cooler, damper conditions slow their finishes. For how much to buy, the finish coverage calculator uses these same coverage figures. Every finish side by side: the finish dry time chart. What the federal rules say about finishes and food: food-contact finishes.
Elsewhere in finishing: shellac and the shellac cut calculator; for repairs before the finish, wood filler vs wood putty; and for the glue-up, wood glue types.