General Finishes Stain Blocker - Quart

$ 40

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

Stain Blocker is General Finishes' revolutionary water-based stain-blocking primer for interior projects. Stain Blocker can be used to protect pigmented finishes from stain, dye, and wood tannin bleed-through. Brush or spray over an existing finish, raw wood, or MDF as a base coat for light-colored General Finishes Milk Paint and Pigmented Polys. 

This primer has a sophisticated resin system and an atypical formulation. Use on pieces where you are concerned about bleed-through. For DIY customers or professionals painting a surface any shade of white or light gray, look no further than General Finishes Stain Blocker.

Also available in gallons.

Don't forget your brushes and sandpaper!

Note: Do not thin Stain Blocker with anything but distilled water. Do not add more than 5% distilled water. Do not use water-based products with Linseed Oils or Danish Oils.


Base Type: Water
Interior or Exterior: Interior only
Type: Stain Blocking Primer
Tintable: No
Coats: 2 coats
Application Method: Brush, Roll, Spray
Usable over existing finishes: Yes
Spray Tip Sizes: HVLP 1.8-2 mm
Dry Time - Recoat: 2+ hrs.
Coverage: 125-150 sq. ft.
Viscosity: Thick


Raw Wood

  • Sanding Schedule: 120-grit followed by 150- or 220-grit
  • Remove dust with a water-dampened rag or oil-free tack cloth.
  • Let dry completely before applying GF product.

Sealed Surface

  • Scuff clean with a non-woven abrasive pad and a 50:50 mix of denatured alcohol and water. Dry 1-2 hours. Avoid cleaning with products containing phosphates (salt), which can linger in the substrate and produce a white haze.
  • Sand lightly with a fine-grade (220-320) sanding pad.
  • Remove dust with a vacuum, compressed air, an oil-free tack cloth or a water-dampened rag.
  • Let dry completely before applying General Finishes product.
  • Work in a well-ventilated area.
  • Stir thoroughly to reincorporate solids that have settled to the bottom of the can before and throughout the application process.
  • Test for adhesion over existing finishes and test entire finishing process. Not all bleed-through can be prevented with primer.
  • Do not mix or tint with paint, stain, or topcoat as contamination from other finishes will cause product failure.
  • Thin with caution up to 5% with water only. Over-thinning will reduce the stain blocking properties.
  • Rinse applicators & spray guns with water immediately after use.
  • Apply 2 coats.
  • Hand application: Apply using a synthetic bristle brush, foam brush, pad applicator or roller with smooth, even strokes.
  • Spray application: Before spraying, strain paint through a medium-mesh filter. Spray wet films at 3-5-mil thickness. HVLP: 1.8mm-2.0mm spray tip, medium air cap. Verify tip sizes with your equipment supplier. See our spray tip size recommendations here. 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 (NIOSH/MSHA approved) respiratory & eye protection and work in a ventilated space. Visit this FAQ for more information on spraying techniques.
  • Face frames on cabinets: Stain Blocker can be applied successfully to cabinet face frames, edges or drawers with a brush, pad applicator or small cabinet-specific roller such as Whizz or AllPro brand.
  • Finish sand between coats with a 220-320 grit sanding pad to improve smoothness and adhesion. Do not use conventional steel wool.
  • Remove dust with a vacuum, compressed air, an oil-free tack cloth or a water-dampened rag.
  • Increase dry time if:
    • Humidity is over 80%
    • Cooler Temperatures
    • Thick coats are applied
    • Applying over products from other brands
    • Layering General Finishes water- and oil-based products:
      • Water over oil: Let oil-based products dry 72+hrs before applying water-based products
      • Oil over water: Let water-based products dry 24+hrs before applying oil-based products


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