Bleeding
TRB0002
Causes
- Solubility of certain dyes and pigments when overcoated, causing topcoat colour to be slightly tainted
- Excessive amounts of peroxide hardeners in polyester fillers
- Traces of tar-underseal can bleed when oversprayed
Prevention
- Old colurs can be tested for bleeding by applying a light colour (white) over a small area and leaving for a few minutes. Bleeding will generally occur after a few minutes. Do not allow spray dust from bleeding colours to fall on other jobs
- Only use the recommended amount of peroxide hardener in polyester fillers
- Remove all traces of road tar and underseal during preparation
Rectification
- The best way to rectify an area of bleeding is to totally remove the paint and then re-coat. Alternatively, the use of isolator/sealers can seal in the bleed. However, avoid thick films of the isolator/sealer
- Bleeds occuring from peroxide hardeners can be sealed by the application of a polyester primer surfacer