Bleeding
Definition
Diffusion of a soluble dye from the substrate through a paint system. In most cases, bleeding leads to a spot-like discoloration of the topcoat, often producing a reddish or yellowish color shade. Excessive peroxide in a polyester body filler can also cause similar stains due to a chemical reaction with the pigments.
Causes
- Excessive peroxide from a polyester body filler causes a yellow-brownish stain in the topcoat. Blue and green colors are particularly vulnerable to this problem
- Soluble dyes from the old paintwork are dissolved by the solvent of the repair materials and thus change the color of the surface.
- Residues from bitumen and tar.
HOW TO AVOID
- Only use the recommended amount of peroxide hardener for the polyester body filler. Mix hardener and body filler thoroughly.
- Carry out a solvent test. Soluble dyes have not been used in OEM coatings and in any Glasurit repair materials for many years.
- Remove all residues from bitumen and tar before painting.
REPAIR
To repair areas damaged by “bleeding”, use suitable isolating products, such as Glasurit 1109-1240/4 Stone Chip and Underbody Protection or Glasurit 801-72 VOC EP Primer Filler, if applicable. In case of major damages, sand the paint system down to a “sound” surface. Refinish using the recommended undercoats and topcoats.