Blistering on Wing Keel

[Ceilidh II]

My 1987 C34 wing keel that has developed some blistering on both starboard and port sides of wing keel. I can not tell if previous owner attempted to address the problem and it did not work or if it is just the slag becoming loose with age. I am finding a red rust coloured dust just above the lead and the top layer of the keel just comes away in my hands.  In any case I have started the process of repair and I am wondering if anyone else has come across this problem and what advise might you have. My plan is to take a grinder and get down to lead then build back up with Interlux Watertight, smoothing as I go, then primer and anti-fouling.
Open to any suggestions.
David
CeilidhII

[hump180]

Had the same problem and you are on the right track and I posted about this some time before. I chipped away what was loose, then ground down to fresh lead with a wire wheel on a drill. Once we removed the bad slag we used west system epoxy as it was recommended. When you get to the lead you can coat with a layer of west system to encapsulate (wire brush it in),  and then fill with thickened epoxy (410 microlight filler and epoxy) , then sand it fair. Barrier coat and bottom paint - no more problems. Now most important - protect yourself from lead dust. Wear a mask and gloves at the least.