Staining/plastic bleed through

Yellow-brown discolouration appears in the topcoat over areas repaired with polyester body filler or glazing putty.

Cause:

1. Using too much or too little hardener in the putty/filler .
2. Insufficient mixing of putty/filler components.
3. Applying a surfacer, sealer and/or topcoat before putty/filler has thoroughly cured.
4. Applying undercoats and/or topcoats excessively wet.
5. Clear coating a white or light colour without using stain-free body filler.

Repair:

1. Allow topcoat to thoroughly cure.
2. Sand affected area, isolate with two component undercoats and refinish.

Prevention:

1. Use correct amount of body filler hardener.
2. Mix components thoroughly.
3. Allow putty/filler to cure thoroughly before topcoating.
4. Apply undercoats and/or topcoats in medium-wet to wet coats. Always allowing proper flash time between coats.
   
5. Use non-staining body filler, especially when clearcoating light colours.
6. Isolate suspected staining filler by applying a two-component surfacer and sealer. Allow to cure, following product recommendations then apply desired topcoat.