Knot bleeding

 

Knot bleeding

Causes

  1. This problem usually affects woods with knots containing resin (pine, spruce and fir). Solvents in coatings dissolve resin. During the drying process, solvents evaporate through the paint film giving it a brownish colouration. Knot bleeding is not the same as resinous exudation which occurs under heat or sun. In such case, the resin oozes through the coating giving it a yellowish colouration after a few months.

Solutions

  1. Seal bare wood knots with a shellac. Apply a solvent-based primer-sealer, GoPrime 190-135 or Polyprep 145-022.