Traditional Amber Urethane Application Troubleshooting Guide

The application of BRISTOL FINISH Traditional Amber Urethane requires the same basic preparation steps as any conventional coating product.  The old saying is completely true – proper preparation and application accounts for 90% of the final appearance and expected performance.

The Finish is developing Bubbles (reasons/possible causes)

  • If you are going onto bare wood for the first coat.
    Some wood, especially very porous wood types like mahogany can have excess air trapped in the wood grain. If bubbles form immediately, break bubbles with the brush by GENTLY applying another coat right away. You may also thin the working batch 5% to 10% with Bristol Finish Thinner, our Tropical Reducer, or acetone.
  • You may be overworking the applicator (over- brushing).
    Do not over brush the coating during application. This can mix excess air into the coating. Lay the coating on gently with a minimum of brush strokes.
  • There is too much wind or air movement.
    This can cause skin drying, leaving trapped solvent. Don’t perform brightwork projects on days that are too windy.
  • The coating is being applied too thickly.
    This can cause also skin drying, leaving trapped solvent. Brush on or spray a nice, thin even coat.
  • Applying cool material onto a hot surface?
    This can cause thermal shock. On a 70°F day in full sun, the surface may be over 100°F. If the coating material is stored below decks in a boat, or indoors in the shade, there may be too great a temperature differential. Warm the mixed working batch next to the project piece for 15 minutes or so.
  • There is moisture present.
    If the surface has too great a moisture content, or if the working equipment has moisture present, it will react with the urethane chemistry to produce carbon dioxide, and cause bubbles. Make sure the working piece is completely dry, and also the application equipment.
  • There is surface contamination.
    Oil, soap or wax contamination may cause bubbling or fisheyes (craters). Insure that the project surface is completely clean before application.