Skip to content
Woodworking Math

Spar urethane

General Finishes Exterior 450

The figures General Finishes prints for General Finishes Exterior 450 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
30 min
Recoat
2 h
Ready for use
Not on the sheet we read
Full cure
21 days
Coverage
up to 600 sq ft per gallon
Thinning
Water, GF Extender or GF Accelerator
VOC
Under 123 g/L
Conditions
70 °F, 50 % RH
Indoors or out
Interior and exterior
Food contact
The sheet we read makes no food-contact statement

One source: General Finishes, the maker of that product

From the sheet: Water-based acrylic/urethane blend with UV absorbers.

What the maker names it for

Against its kind

General Finishes Exterior 450 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. General Finishes, Exterior 450 Topcoat technical data sheet (July 2025), read 2026-11-07.

How the tags work: How we source every number.