Rusty keels - primocon?

[ianabc]

Zinc rich primer....

Zinc rich primers are considered to be self healing in that microscopic imperfections and scratches in the zinc primer coating will self repair by the electrically active zinc.

What is supposed to happen is that the zinc protects the scratched or exposed metal, zinc plating the metal.

Next coat after coat of high build epoxy.

Next fillers and

then cosmetic coats.

 

[BOATPOWER]

Primocon problems

Just a little more info on zinc or aluminum rich primers:
I worked in a haulout yard in Fremantle for 3 years where steel trawlers were serviced. My luck at having such a wealth of experience led to getting the best advice to paint the boat. Zinc rich and alum rich paint such as Primocon was definitely a problem. The paint is designed to sacrifice to protect the steel. When metal such as zinc steel or alum sacrifices (rusts) it swells and will eventually push off any other coating put on above it, also it does not provide as strong and adhesion to the steel as a direct epoxy coating. Putting 6 coats of Primocon will just delay the time it takes to show up. Protection against the odd scratch from reefs and grounding is well taken care of from the anodes and can be touched up at a convenient later date. Our Yacht is a twin keeler and we often take the ground so can vouch for the excellent protection and strength of a direct epoxy coating.
If the hull has zinc or alum rich primer it would at first sacrifice itself to protect any scratch the hull took and then keep sacrificing from under good paint until the problem becomes much bigger.

 

[theoldplucker]

How does one manage to all these treatments on a beach layup between tides ? !!!

 

[Dan the man]

momentarily confused thinking why a rust converter would be called Vatican....