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A gallon is the practical size for a fence run, a garage door, an entry door with sidelights or a full set of patio furniture. Exterior 450 is General Finishes' water-based urethane/acrylic clear for outdoor wood that stands upright: it carries UV absorbers that protect the film plus a mildewcide, stays water-white rather than ambering, and is not a deck finish. The TDS rates Satin at 30 on the sheen scale and asks for at least three total coats, with no separate sealer needed.
Free shipping at $75, no code needed (lower 48 + DC). Unopened cans can be returned within 30 days with a prepaid label; opened paint can't (refund policy).
GF's product page puts coverage at about 560 to 640 sq ft per gallon per coat. Divided over three coats that is about 185 to 210 sq ft of finished surface, a little more if two coats suffice on a sheltered piece. The TDS calls for 3 to 5 mils wet per coat and 2.5 to 5 mils dry for the full build. Store leftover between 50 and 80 F; GF says an unopened can conservatively lasts up to 5 years.
Sand raw wood no finer than 220 grit; the TDS cautions that sanding too smooth can reduce adhesion and leave an orange-peel texture. Prefinished wood gets scrubbed with a maroon pad and a 50/50 mix of denatured alcohol and water, then a light sanding. Don't put Exterior 450 over linseed or Danish oil, or over white and pale paint, which can yellow. Exterior finishes are maintenance coatings; GF's chemist Ryan Denny puts it plainly: Mother Nature will always win over one application. Plan a cleaning and fresh coat every few seasons. VOC is under 123 g/L per the TDS, which lists SCAQMD, CARB, Canada and OTC compliance.
Smaller jobs: Exterior 450 Satin Quart. Lower sheen: Exterior 450 Flat Gallon.
How soon can a finished piece go outside? General Finishes recommends waiting 5 to 6 days so the finish can cure a bit first. Exterior 450 keeps hardening for about 20 to 21 days.
Exterior 450 or GF Outdoor Oil? GF says Outdoor Oil soaks into the wood, is quicker to apply, can go on decks and typically needs reapplying about once a year. Exterior 450 builds a film with better moisture and UV protection, isn't meant for big horizontal surfaces such as decks, and typically lasts 3 to 5 years before recoating.
How do I keep a Douglas fir door from blotching under Exterior 450 stain? GF suggests a 50/50 mix of your Exterior 450 stain color and Exterior 450 Clear as a conditioner. Let it dry 2 to 3 hours, longer when humid, then stain. GF warns blotching can still happen.
Sources for this Satin gallon: the Exterior 450 technical data sheet, the GF Exterior 450 page, and GF's FAQ answers on outdoor timing, Outdoor Oil vs Exterior 450 and Douglas fir. Browse General Finishes.
Documents are published by General Finishes. Always follow the label and SDS.
Free standard shipping on orders $75+ to the lower 48 states and DC. Some large or heavy items are excluded at checkout.
30-day returns on unused, unopened items. Returns accepted within 30 days. We send you a prepaid return label. Contact us within 30 days of delivery to start a return. Opened paint, aerosols, flammables, special orders and sale items can't be returned. Read the full refund policy.
Use this product page for the exact item, then check the Weekend Project Carts for prep, applicators, patch, cleanup, and finishing supplies. If you are still choosing a method, start with the Project Guides before adding everything to cart.
