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Bleeding

Definition

Diffusion of a soluble dye from the substrate through a paint system. In most cases, bleeding leads to a spot-like discolouration of the topcoat, often producing a reddish or yellowish colour shade. Excessive peroxide in a polyester body filler can also cause similar stains due to a chemical reaction with the pigments.

Causes

  1. Excessive peroxide from a polyester body filler causes a yellow-brownish stain in the topcoat. Blue and green colours are particularly vulnerable to this problem
  2. Soluble dyes from the old paintwork are dissolved by the solvent of the repair materials, changing the colour of the surface.
  3. Residues from bitumen and tar.
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HOW TO AVOID

  1. Only use the recommended amount of peroxide hardener for the polyester body filler. Mix hardener and body filler thoroughly.
  2. Carry out a solvent test. Soluble dyes have not been used in OEM coatings or any Glasurit repair materials for many years.
  3. 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. Where there is major damage, sand the paint system down to a sound surface. Refinish using the recommended undercoats and topcoats.