Blushing

€0.00 €0.00
Levertijd:
Blushing During the drying of a freshly applied layer of epoxy a white deposit may occur on the coating. This phenomenon called blushing. Blushing is not beautiful to see, but has no effect on the properties of the coating. Why is it? Epoxies generally cure with a (poly) amine / amide-based hardener. This hardener causes a hard, dense and chemically resistant layer. After the mixing of the two components start the reaction between the epoxy (base), and amine / amide (curing agent). The mixed product can be made for a certain period of time. That time is called pot life. After the expiry of that period, the coating is too thick to process. Blushing can occur when during the drying of the freshly applied epoxy layer, is increasing the humidity. Even when rain falls on the surface, there may arise a white deposit. This is because the curing agent (to the wet surface) reacts with moisture in place of the molecules in the epoxy. What to do when applying paint next layer? The white film is only on the surface of the coating and as I said not affect the properties of the coating alone is not so nice. A bigger problem occurs when there is a subsequent coat of paint to be applied to the whitened coating. The white coating adhesion of the next layer can strongly influence. To obtain good adhesion to the white residue must be removed. This can be done by: - The blushing intensive wash off with clean water and detergent. - The white layer on the light to be sanded with a fine sandpaper. In order to verify that the white deposit has been removed, one can carry out a test with pH paper, and demi water. When the number pH 7 (neutral) is, one can assume that the stop is removed. During the winter, the chance of blushing greater than in summer. This is mainly due to the low temperature and higher humidity. Drying will be slower. The type of hardener influences the onset of blushing. Hardeners which have chemical resistance, are more 'blush sensitive "than those used in atmospheric coatings.
More Information
Article number Q1
Manufacturer Jotun
Write Your Own Review
You're reviewing:Blushing