General Finishes Water-Based Exterior 450 Topcoats - Quart

$ 38.99

Have questions? Give us a call at 260-637-0054.


Exterior 450 Topcoat a clear-drying low VOC finish suitable for vertical exterior surfaces, such as fences, patio furniture, garage doors and entrance doors. It is not recommended as a deck finish. Exterior 450 is fortified with UV absorbers to stabilize and protect the integrity the finish*, and built-in mildewcides to slow mold and mildew growth. It performs well as a clear coat or as an optional topcoat over darker color General Finishes Milk Paint**. Do not use over light or white paints as yellowing may occur.

Exterior 450 Topcoat is not intended for decks. It can be used on tabletops that do not receive direct exposure to sun and rain. As with all fine furniture finishes, wipe up spills in a timely manner to protect the finish.

Don't forget your brushes and sandpaper!

*The UV additive in 450 Clear will protect the integrity of the film, but will not prevent the wood from changing color from sunlight. Brush or spray.

**Do NOT use Exterior 450 or any other clear coat, over white or light paints such as GF Milk Paint, or GF White Poly as it may cause yellowing. Any clear coat can become reactive over wood substrates or existing finishes, causing tannin or dye bleed-though regardless of priming. All of GF's white paints do NOT require a topcoat. 

Note: Exterior 450 is designed to let the water permeate the finishas it dries, the water releases back out to allow the finish to tighten down again. Temporary cloudiness may occur as the finish dries. The UV additive in 450 Clear will protect the integrity of the finish, but will not prevent the wood from changing color from sunlight.

Warning: We do not recommend Exterior 450 stains or topcoats for exotic woods Ipe, Teak, or other dense oily woods that will get exposure. 


Product Colors: Water White in can (dries clear)
Base Type: Water
Ambering: No
Sheen: Flat (10 or less), Satin (25-35), Semi-Gloss (50-60), Gloss (80+)
Interior or Exterior: Exterior
Tintable: Yes
Type: Urethane/Acrylic Blend
Coats: 2 - 3 coats
Application Method: Brush, Roll, Spray
Usable over existing finishes: Yes
Spray Tip Sizes: HVLP 1.1mm-1.3mm
Dry Time - Touch: 30+ min.
Dry Time - Recoat: 2+ hrs.
Dry Time - Light Use: 7-10 days
Dry Time - Cure: 21 days
Coverage: 140-160 sq. ft.
Viscosity: Medium
Durability (Highest, High, Medium, Low): High


Raw wood

  • 120-grit sandpaper followed by 150-grit or 220-grit sandpaper. Do not over-sand with fine-grit sandpapersthis will close and seal the wood grain, preventing ideal color absorption. Also, do NOT use steel wool on water-based based finishesthe particles will get trapped in the finish and rust.
  • Remove dust with a vacuum, compressed air, an oil-free tack cloth or a water-dampened rag.
  • Let dry completely before applying General Finishes Exterior 450.

Sealed surface

  • Scuff clean with a non-woven abrasive pad &amp50:50 mix of denatured alcohol &ampwater.
  • Dry 1-2 hours.
  • Sand lightly with 220-320 grit sanding sponge.
  • Remove dust.

Newly stained surface

  • Do not sand.
  • Apply directly to stained surface.
  • Work in a well ventilated area.
  • Stir topcoat to reincorporate solids that have settled to the bottom of the can before and throughout the application process. Do not shake.
  • Test for adhesion when applying over an existing finish.
  • Thin as desired with distilled waterstart with 5%, adding up to 10% by volume.
  • Increase open time, if needed, with 10-15% General Finishes Extender if allowed by local regulations. GF Extender will improve flow and leveling and increase open time, which is helpful in dry climates. California Residents: Adding more than 2% of GF Extender will make the products non-compliant per SCAQMD Regulations.
  • Apply 2-3 coats of Exterior 450. No more than three coats is recommended. More coats will not improve durability.
  • Hand application: Apply a liberal amount of product using a synthetic bristle brush, foam brush, pad applicator or roller. Avoid pressure and excessive back-brushing. Brush along the wood grain using smooth, even strokes with light lap marks. Let lap marks drythey WILL tighten down.
  • Spray application: Before spraying, strain topcoat through a fine-mesh filter. Spray wet films at 3-5-mil thickness. HVLP: 1.1mm-1.3mm spray tip, medium air cap. Verify tip sizes with your equipment supplier. Keep your gun at a 90° angle, 6-8" from the surface. On large, flat areas, use wet, even patterns 6-8" wide. For narrow surfaces, reduce the fan pattern to 2-3" wide to reduce overspray. Overlap each pass 25% to conceal lines. Wear a full filter respirator (NIOSH/MSHA approved) and work in a ventilated space.
  • Finish sand between coats with a 220-320 sanding sponge to improve smoothness and adhesion. Do not use steel wool.
  • Remove dust with a vacuum, compressed air, an oil-free tack cloth or a water-dampened rag.


Customer Reviews

Based on 1 review
ed rementer
Great stuff

Finally after 17 years and 7 re-do's of the doors, this product is showing that it's going to hold up longer than a few months. I'll know better the outcome after the winter of 22'.