tryingtosail
New member
Hi looking at a boat, hull looks as if it is "chalked" is that a bad sign?
what does chalking mean?
- Thread starter tryingtosail
- Start date
AndrewB
Well-known member
Chalking is a condition of paint failure. It is the result of breakdown of the paint binder allowing release of pigment, as a consequence of poor application, UV or weather degradation. The symptom is a chalky feel and even powder when you run your finger over it.
It depends a bit on what type of paint you've used. Cheaper acrylic and enamel paints always chalk after a while - sooner rather than later if you have used interior grade paint. With two pack epoxy and polyurethane, early chalking is a sign of a poor mix, insufficient catalyst, or application at too low a temperature. Its rarely so bad that one cannot just rub back, wash with thinner, and recoat.
Chalking also occurs on gelcoat with older GRP yachts - after all gelcoat is not so very different from polyurethane paint. Others can advise on the implications here, there is currently a thread below on 'dull boat' for example.
It depends a bit on what type of paint you've used. Cheaper acrylic and enamel paints always chalk after a while - sooner rather than later if you have used interior grade paint. With two pack epoxy and polyurethane, early chalking is a sign of a poor mix, insufficient catalyst, or application at too low a temperature. Its rarely so bad that one cannot just rub back, wash with thinner, and recoat.
Chalking also occurs on gelcoat with older GRP yachts - after all gelcoat is not so very different from polyurethane paint. Others can advise on the implications here, there is currently a thread below on 'dull boat' for example.
jerryat
Active member
Hi! This term is a generic term covering any finish that has the characteristics noted by AndrewB. Commomly applied to GRP finishes, it is most noticable on darker colours e.g. reds and blues, and gives the effect of someone having rubbed or dusted the surface with chalk. Often this can be removed via abrasive polishes/ pastes to 'cut back' the chalk and restore the (almost) original colour.
There have been many threads on this subject, so a search will give you a huge amount of info and opinion.
Good luck
Jerry
There have been many threads on this subject, so a search will give you a huge amount of info and opinion.
Good luck
Jerry
snowleopard
Active member
i had it happen with international 2-pack when dew formed on freshly-set paint.
a mild case on gelcoat can be cleared up with T-cut.
a mild case on gelcoat can be cleared up with T-cut.
30boat
N/A
Epoxy paint will chalk for sure if used outside.Its ultraviolet resistance is very low and should always be painted over with a suitable product such as poliurethane paint,two pack preferably.
Other threads that may be of interest
