Stain Blocker is General Finishes's revolutionary water-based white primer for
interior projects. Stain Blocker can be used to protect pigmented finishes from
stain, dye and wood tannin bleed-through. Use over an existing finish, raw wood
or MDF as a base coat for light colored
General Finishes Milk Paint,
and Pigmented Polys.
General Finishes Stain Blocker is designed for effectiveness, not price point.
A successful primer requires a sophisticated resin system and an atypical formulation.
Use on pieces where you are concerned about bleed-through.
Please click the below headers to reveal the instructional info for this product.
Step 1: Preparation for Stain Blocker
All wood projects require preparation sanding, and all existing finishes
require prep cleaning and sanding. If you skip this critical step, your
finish may fail.
Preparation for Raw Wood or Stained Raw Wood Projects
For high-use areas with heavy grime build-up and oil from hands,
give your project a deeper cleaning.
- Scuff clean with a Scotch Brite™ 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. If your project requires a deeper cleaning, see Power
Prep Cleaning Highly Used Existing Finishes below.
- Sand lightly with a fine-grade (220-320) foam 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.
Power Prep Cleaning Highly Used Existing Finishes
For high-use areas such as kitchen cabinets or table tops with heavy
grime build-up and oil from hands, give your project a "Power" clean.
- Scrub clean with a detergent, such as Spic and Span or Dawn, using a Scotch Brite™ pad.
- Rinse well with water.
- Scrub clean with a Scotch Brite™ pad and a 50:50 mix of denatured alcohol and water. Dry 1-2 hours.
- Sand lightly with a fine-grade (220-320) foam 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.
Alternative Cleaning Solutions For Existing Finishes (Not as aggressive
or effective as denatured alcohol; requires rinsing.)
- 50:50 mix of bleach and water
- 50:50 mix of vinegar and water
- Mineral spirits can be used when working with water-based products,
but only if the surface is thoroughly rinsed and allowed to dry for
72 hours.
- If you use with products containing phosphates (salt), which can
linger in the substrate and produce a white haze, be sure to rinse
thoroughly.
Step 2: How to Apply General Finishes Stain Blocker
General Finishes Stain Blocker is our strongest primer for light colored paints
and acts as a chemical barrier that adheres well to prepped interior raw wood
and previous existing finishes. Two coats are required. The first coat will
absorb bleed-through which can cause a slight color change to gray, and the
second coat will seal the bleed-through.
Stain Blocker Application Steps
- Stir paint to reincorporate solids that have settled to the bottom of the can before and throughout the application process.
- Thinning: Do not thin.
- Apply 2 coats of Stain Blocker under all light paints.
- Hand application: Apply using a synthetic bristle brush, foam brush,
paint pad applicator or roller.
- 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 general guide for spray tip sizes.
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.
- Face frames on cabinets: Stain Blocker can be applied successfully to
cabinet face frames, edges or drawers with a brush, pad or small
cabinet-specific roller such as Whizz or AllPro brand.
Dry 2+ hours between coats and before topcoat in ideal conditions: 70°F/20°C;
50-70% humidity. Be sure to allow adequate dry time. You can tell if a water-based
finish is dry if it forms a powder when lightly sanded with a fine-grade (220-320)
foam sanding pad. If in doubt, wait longer. Rushing dry time can cause
clouding/blush in topcoat due to moisture trapped between coats. Increase dry time if:
- Humidity is over 80%
- Thick coats are applied
- Applying over a previously existing finish
- 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
Finish sand between coats with a fine-grade (220-320) foam sanding pad to improve smoothness and adhesion.
Remove dust with a vacuum, compressed air, an oil-free tack cloth or a water-dampened rag.
Apply 2-3 coats of paint and then seal with 3 coats of topcoat.
Cure Time
Water-based finishes cure and harden for full use after 21 days in ideal
conditions. Avoid placing heavy objects on surfaces that have not completely
cured. Treat gently, and do not clean with commercial products during the
curing period.
What else you need to know:
- DO NOT tint Stain Blocker or mix with any paint, stain or topcoat. Contamination from other finishes will cause product failure.
- Interior use only under pigmented finishes.
- Stain Blocker does not adhere to melamine.
Warning: Do not use water-based products with Linseed Oils or Danish Oils.
Storage of Water-Based Products
Please be mindful of the manner in which water-based products are stored
and how long they have been in storage. They are not a forever product.
Life of Product
Water-based products do not last forever, even when unopened. General Finishes
products are best used within 1 year of the manufacture date listed on the can.
However, the life of the product may be extended with proper care and storage (see Storage Tips below).
Water-based products can last 3-5 years if the can is unopened, in good
condition and stored in correct temperatures.
Product that is 3 years old will not look like product that is 6 months
to 1 year old. You will see more stratification or separation as the product
ages. Always stir thoroughly before using.
Foul Smell
If your product has a foul smell, it is contaminated and no longer in
useable condition.
Clumps & Settling
Gravity can cause some solids to settle on the bottom of the can and slight
separation on the top. This is normal. If working with older product stir
with a paint mixing attachment on a drill.
If the solids dissolve and clumps smooth out after mixing from the bottom,
the product is in good condition for use.
Inability to reincorporate large, chunky lumps after stirring for several
minutes is an indication that the product has frozen and can no longer be used.
Storage Tips
Water-based finishes crystalize and form a skin due to evaporation when
the air-tight seal on a can is broken at first use. The following best
practices will increase the life of your product:
- Pry open sealed lids with a paint can opener by hooking under the lid's
rolled edge. The use of a screwdriver can disfigure the rim and lid,
impairing a complete seal.
- Keep lid closed while working. Pour what you will use into a bowl, paper
cup, or plate, and close can lid as you work.
- Clean the chime of the can thoroughly with a paper towel before closing
to create a complete seal. Product falling into the chime can be minimized
by using a pouring lid, such as Fitsall. Avoid wiping used brushes on the lid.
- Pound the lid in place using a rubber mallet to avoid distorting the
chime or lid. Dents in the lid from direct contact with a hammer can impair
a complete seal. Alternatively, place a flat piece of wood over can lid
and firmly pound shut.
- Store in moderate temperatures. Avoid temperatures below 50°F/10°C or
above 100°F/26°C. Keep from freezing. Frozen and heat-damaged product
cannot be revitalized. Temperature-controlled spaces, such as a basement,
are ideal for storage. Do not store product in an attic, garage, in
direct sunlight, or next to something warm like a water heater or furnace.
- Store can upside down to create a liquid seal, minimize evaporation and
reduce the chance of crystallization. Decant remaining product from the
can before stirring.
- Decant leftovers to a smaller container when the finish is almost used
up. Alternative storage containers for water-based products are plastic
FIFO bottles or glass bottles. Do not fill metal-lidded containers
completely to prevent them from rusting.
The following water-based product mistures can be stored:
- Product thinned with up to 15%
General Finishes Extender
or General Finishes
Accelerator, with the exception of thinned General Finishes
Water Based Wood Stain.
- Mixtures involving colors & sheens within the same product line, such as:
- High Performance Satin + High Performance Gloss
- Snow White Milk Paint + Coastal Blue Milk Paint
- Amber Dye Stain + Merlot Dye Stain
The following product mixtures should NOT be stored:
- Any water based product with thinned tap water; water often contains
bacteria that will adversely affect stored paint.
- Topcoat + Stain or Paint
- Milk Paint + Chalk Style Paint
- Water Based Wood Stain + Dye Stain
Furniture Care & Maintenance
Cure First
You have just finished applying a fine furniture finish. Treat gently
until the paint or topcoat have fully cured. Allow 21 days for a water-based
finish to cure and 30 days for an oil-based finish to cure before cleaning.
Regular Cleaning and Maintenance
- Remove dust with a water-dampened cloth. Dust can build up over time
and may scratch or dull finishes if not removed regularly.
- Remove fingerprints, cooking fumes and smoking residue with mild soap
and water. These contaminants will not harm the finish, but they accumulate
on surfaces and dull the original luster.
- As with all fine furniture finishes, avoid using furniture polish,
cleaners or dusting sprays that contain silicone, alcohol, ammonia and
anything acidic. Exception: We have successfully cleaned with Clorox wipes.
- Clean up water, alcohol and food spills in a timely manner and use
placemats & coasters to protect the finish.
- Future finishes or touch-ups may not adhere properly or perform as
desired over a contaminated surface. Some contaminants, such as silicone,
seep through finish into the wood and often cannot be removed.
- Avoid excessive exposure to direct sunlight, high temperatures or
high humidity. These can damage furniture and finishes.
Supporting Instructional Videos