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Woodworking Math

Spar urethane

Varathane Oil-Based Spar Urethane

The figures Rust-Oleum (Varathane) prints for Varathane Oil-Based Spar Urethane on its own data sheet, at the conditions it names. Where the sheet doesn't give a figure, this page says so rather than borrow one from another product.

Dry to the touch
2 h
Recoat
8 h
Ready for use
24 h (light use (full use after 3 days))
Full cure
Not on the sheet we read
Coverage
380–760 sq ft per gallon
Thinning
Do not thin
VOC
Under 350 g/L
Conditions
70 °F, 50 % RH; apply at 55–90 °F
Indoors or out
Interior and exterior
Food contact
The sheet we read makes no food-contact statement

One source: Rust-Oleum (Varathane), the maker of that product

From the sheet: Handle after 4–6 hours; sand lightly if a coat has dried more than 12 hours. Rust-Oleum names railings, fences, patio furniture, house and trim, and not decks, high-traffic areas, siding or rough-sawn wood.

What the maker names it for

Against its kind

Varathane Oil-Based Spar Urethane is one of the products in outdoor clear finishes; here is that kind across every maker we have read.

Outdoor clear finishes: recoat across makers

4 h

span 2–8 h

Median of 3 sources

Outdoor clear finishes: coverage across makers

570 sq ft/gal

span 380–760 sq ft/gal, per coat

Median of 3 sources

Related

Work it out for your project

Sources

  1. Rust-Oleum (Varathane), Varathane Oil-Based Spar Urethane technical data VAR-02, Rev. 050614 (retailer-hosted copy), read 2026-11-07.

How the tags work: How we source every number.