General Finishes Stain Blocker is designed for effectiveness, not price point. A successful primer requires a sophisticated resin system and an atypical formulation, which will result in a more expensive product. To maximize GFSB's effectiveness, our chemists formulated this product with the highest quality ingredients. Use ONLY for those pieces where you will really care if there is bleed through. GFSB will work every time, not some of the time. SURFACE PREPARATION: Existing Finishes (stain, lacquer, paint): Clean
and remove grime, grease or loose paint. Wash down extremely dirty surfaces with a mix of 50/50 denatured alcohol and water or a sulfate-free commercial cleaner. Remove any heavy buildup with a synthetic wool pad. Allow surface to dry completely. Prep sand the surface with 220 grit sand paper and remove dust. Raw Wood: Sand with wood grain. Prep sand with 120 then 220 grit paper. Remove dust. APPLICATION: Stir thoroughly. It is essential to apply 2 coats. The first coat will absorb contaminents in the wood, causing a color change during the first application, and the second will seal them. Brush or Roller: Apply a uniform coat with a high quality synthetic blend brush or short nap roller. Spray: Product is ready to spray from container and does not require thinning. Strain material through fine mesh filter. Spray medium to wet film 3-5 mil thick. Heavier coats will take longer to dry & cure. Spray with compressed air, HVLP, or Air Assisted Airless. Fluid tip sizes: Compressed Air- .040, HVLP -.043-.061 (1.1mm-1.5mm), AAA -.009-.013. Use medium size air caps.
Specifications
Type
Stain Blocking Primer
Base
Water
Interior / exterior
Interior/Exterior
Color
White
Apply with
Brush, Roll, Spray
Spray tip
HVLP 1.8mm-2.0mm
Coats
2 coats
Dry to touch
1+ hours
Recoat after
2+ hours
Coverage
125-150 sq ft/quart, 500-600 sq ft/gallon
Over an existing finish
Yes
Tintable
No
VOC
<50 g/L
Questions & answers
When do I need Stain Blocker?
When you paint a light color over wood that tends to bleed (oak, mahogany, poplar, pine) or over an existing finish. It is a chemical stain-blocking primer, General Finishes' most advanced. If bleed-through is not a concern, White Undercoat is the simpler choice.
How many coats?
Two. It is dry to the touch in 1+ hour and ready to recoat after 2+ hours.
Can it be tinted or mixed with other products?
No.
Mine is thick and clumpy in the can. Is that normal?
Yes, if it is soft at the bottom. Some settling and thickening comes with time and temperature. Stir it back in (a drill mixer helps). A hard layer at the bottom is not normal.
Is it guaranteed to stop bleed-through?
No primer can promise that. Some mahogany furniture from the late 1920s and early 1930s has a dye finish that can bleed through anything, so avoid light colors on those pieces.
Can I use it outdoors, and how do I apply it?
Yes, it is rated for interior and exterior use. Brush, roll or spray it (an HVLP 1.8 mm to 2.0 mm tip is recommended).
