
Originally Posted by
Peter
A sad sight, it is obviously not working as "anti" fouling.
Looks like a strip and start again. Been there done that got the t shirt. Wet sanding back to gel-coat is a horrible experience.
What was the age of the paint?
Did you personally inspect the paint when the tins were opened?
Were they stirred correctly?
Did they adhere to the timings between coats? Too soon blisters resulting from solvents in the first coats not escaping. Too long surface too shinny and not re- abraded.
Metal based AF paints copper and tin separate out when left standing. If it is not stirred, using powered mixer and or the lid has been left off the solvents will evaporate leaving a viscous liquid with metal content at the bottom. It is very hard and time consuming to mix in this state. Less knowledgeable folk, professionals included will then thin the paint, but still leave the active metal ingredient undisturbed at the bottom of the tin. During the painting process it is imperative to keep the paint properly stirred even in the tray.
Hard AF paints are still expected to erode in order for the active ingredient to be released adding thinner may interfere with this process meaning once the initial active ingredient is washed off no new will be exposed. Thinned paint will also take longer to go green so adding additional coats too soon will trap un-evaporated solvent - blisters! Use of an incompatible thinner, contamination or poor mixing would also explain the the blistering and or poor adhesion.
FWIW Despite the myths surrounding TBT it is not that effective for sailing yachts, because they remain stationary for long periods and do not sail that fast, where the large ships that it was originally designed for are constantly moving. There are also much better AF paints nowadays that are far less "toxic", knowing that your bottom is very toxic, although in your case probably not, are you happy to scrub it in the water or even swim around it?