peeling paint

[Jack]

Hi all,
I am sure we are all scraping and fairing and painting the hulls these days so I am hoping that someone can help with a question. When the roller goes over some areas the old paint pulls off of the hull and sticks to the roller. We experienced this a little bit last season but this year it was considerably worse. What looks to be well adhered paint turns out to be paint only adhered to itself. As soon as the roller hits it it sticks and comes off.

Where did we go wrong? Was it the original prep? The primer? The paint choice?

We are using the WM ablative. Not sure of the original primer but the hull was prepped, painted and delivered by the broker in 2007. We have painted it ourselves since then.

We have thought of stripping all the paint off and starting over but that seems like such a waste of paint, not to mention not so hot for the environment.

Any thoughts would be greatly appreciated.

thanks,
J&R

 

[Bob McL]

I would strip off the old and start again. No amount of surface work will correct whats under.

 

[RichH]

Typical when ablative paints become 'built up' and the layers are thick. Probably what has happened is that the older 'below' layers have ablated away through leaching, etc. and have lost their adhesion.
The obvious is to remove all such zones and apply new.

FWIW - Since Im not into self inflicted shoulder-bursitis anymore, and still want a smooth and fair surface, what I do is use a plastic hammer and beat hell out of the zones with poor adhesion until I cant flake-off any more with the hammer, putty knife etc., sand the 'base' of the 'craters', and then 'fill'/fair the craters with a mix of micro-balloons and bottom paint and apply it with a large poly trowel to 'fair' the area smooth. Most times it takes several fills with thickened bottom paint to get to 'fair'. Then, I rough sand and repaint the entire hull ... seems to work and the repaired 'craters' dont reappear.
I like my ablative bottom paint to be smooth as a baby's ass ... easier 'release' of slime, etc. and 'faster boat'. I use a foam roller and 'level' the paint with a trowel to knock down the 'roller pimples' ... I do this in stripes.
I prefer a hull surface thats as smooth as a baby's ass, and I dont use HALF the amount of paint as when using a 'just a roller' .... and I get less 'flaking' because the lessened 'build-up'. Only when I start seeing the contrasting 'indicator' color do I apply ablative bottom paint 'thick'.
My reasoning is that if Im not seeing my blue 'indicator' color showing up, Im putting on too much (red) ablative bottom paint .... I usually put on 8-12,000+ nMi per year.

Also FWIW --- about 5 years ago Interlux probably changed its formulation of Micron CSC and Micron Extra, and those applied layers have a resultant hard texture & 'heavy whitish' cast to them ... and this is especially prone to flaking and no matter what is below or on top of that layer. Those paints in recent years dont seem to have the easily flaking 'hard-whites' in them any more.