Preparation / Application

Surface Preparation
The key to proper adhesion and long-lasting protection is correct surface preparation. In most instances, any surface to which Blue Seal will be applied must be sandblasted by an experienced sandblaster.

Once surface preparation is completed, Blue Seal may be applied using a sprayer, brush and/or trowel.


All metal surfaces must be sandblasted to NACE SP-5 and have a surface profile of four to six (4 – 6) mils). Before the application of Blue Seal Coatings, the substrate must also be free of salts and other chemical impurities and be completely dry.


There are two methods for preparation of concrete surfaces.

Method 1

High-pressure water blast concrete to be coated. In case of chemical contamination, the concrete surface should be water blasted with an industrial detergent additive; thoroughly dry prior to coating.

Method 2

Sweep blast concrete with abrasive blasting media.

Cracks should be filled and reinforced to maintain structural integrity before coating. Blue Seal base coat and fiberglass matting can be used as a reinforcement material.

Brush and Trowel Application
Apply Blue Seal immediately after blasting.

  1. Brush on one layer of Blue Seal Base Coat for adhesion. This coat should be approximately 10 – 15 mils thick. Be sure to rub the Blue Seal Base Coat into the freshly prepared surface to ensure there are no voids in the coating and that the substrate is 100% covered. This is especially critical on more porous surfaces.
  2. Brush on one layer of Blue Seal Reinforcement to build up more mil thickness for added protection and strength.
  3. Trowel on second layer of Blue Seal Reinforcement. This can also be applied with a brush, but for a better end result with less sanding we recommend using a plastic spatula or trowel applicator. Troweling on the second coat of reinforcement will build more mils thickness for strength and fill pits at the same time. With a little practice, the trowel lines can be blended smooth and will not require sanding before top coating.
    NOTE: If pits in the substrate are severe, more coats and/or extra glass flake may be added to the reinforcement to make the Blue Seal thicker.
  4. Sand to smooth any imperfections, runs, drips, or trowel lines from application of reinforcement coats.
  5. Brush on 1 layer of Blue Seal Top Coat to provide a smooth and hydrodynamic surface finish.

Spray Application
The Blue Seal Tank Lining application consists of two coats; a base coat and a topcoat. Each coat is to be applied using spray equipment or brush to a minimum of 20 mils thick. The second coat can be applied as soon as the first coat has cured and should be hard enough to walk on (usually in 2-3 hours).

Blue Seal can be sprayed using conventional airless gelcoat, wet out or fiberglass resin spray equipment. We recommend a spray system that mixes the catalyst with the Blue Seal, or draws from a premixed container.

Clean up
Prior to curing, the equipment can be easily cleaned.
Safety Recommendations
When spraying Blue Seal inside a tank, we recommend full body protection, a fresh air fed mask and or any other confined space safety equipment or procedures.
After coating, the tank should be inspected using a Porosity/Holiday Detector. All inside surfaces of the tank and baffles should be checked and any defects should be coated and re-tested.