Bleeding
Paint Defects
Causes
- Soluble pigments or dyes from the old paintwork are dissolved in the solvent of the repair materials, and change in the shade at the surface
- Bleeding can also occur when excessive peroxide from a polyester filler reacts with the pigments in the repair materials causing a yellow-brown stain
- Blue and green colours are particular vulnerable to this problem
- Residues from Bitumen or Tar if not cleaned off thoroughly
Prevention
- Carry out a solvent test to check if soluble dye exists
- Only use the recommended quantity of peroxide hardener when mixing polyester products and mix the hardener in evenly and thoroughly
- Never allow the coloured hardener to look streaky in the filler when applied
- Before painting ensure all contamination, especially bitumen and tar deposits, are thoroughly removed
How to repair
- To repair a bleed-through area, the whole area should be isolated with an appropriate sealer
- If the bleed through is severe then the paint layers should be removed back to a sound substrate and then be refinished with the correct primer and top-coat process