July 29, 2015
I'm really glad to have this miserable, dirty task come to completion. The removal of the bottom paint was necessary, as mentioned earlier, due to the apparent osmotic blistering across the hull. Once I had a significant portion of the bottom paint removed, and the "barrier coat" sanded down to the original gelcoat, I slowly concluded that the blistering was not through the fiberglass structure, but was due to a poor application of the barrier coat. The blisters seem to be isolated to the layers between the barrier coat and the anti-fouling paint.
Tonight's task was to remove the anti-fouling in order to prepare for sanding the balance of the surface (barrier coat) to arrive at the original gelcoat. Once the gelcoat is reveled, I plan to assess the hull for issues (voids) within the fiberglass structure itself, and then address those will filling and fairing. The photo below shows the port after removal of a majority of the anti-fouling paint.
Another photo of the port side...preparing for sanding application.
Total Time: 1.5 Hrs.
Been there, done that - on our CD36. And I did it (mostly) for the same reason: what I thought were blisters (and we switched to VC17, so the old ablative had to go). Turns out that, just like your experience, there were no osmotic blisters, just water trapped between the barrier coat and the gelcoat. And like you, I concluded that either the prep wasn't sufficient or the PO didn't build up enough thickness to keep the water out. Whatever the case, it was a waste of money on his part and a nuisance for us. Too bad. Good luck with your project! Sorry to see the Westsail go, but sometimes that's the way it goes.
ReplyDeleteYep; there's too much in the schedule to justify keeping and building out the W32 - the bigger boat will come later! The bottom job is a nasty one, but I was happy to see no "real" issues with the hull. I plan on using Jamestown's TotalBoat barrier coat, and the finishing it off with Pettit's SR-40. The CD 36 is a beaut!
ReplyDeleteWhy apply another barrier coat when you've just determined that the old one was actually causing issues where none would have existed before? This is more often than not the case with barrier coats. Consider NOT applying one. You don't need it: it's a solution looking for a problem in your case, and there's a good chance that the same problem will simply arise again. Put your time and money into things that will actually make a positive difference.
ReplyDeleteWell, I have already purchased the epoxy-based barrier coat...and I feel that, if anything, it will serve as a "sealer" and provide another layer of protection between water and glass substrate. I found, through sanding of the bottom paint and old barrier coat, that the adhesion was a little suspect, and I think this ultimately caused the issue of what appeared to be blistering. I plan on taking the bottom down to the original gelcoat, grinding out and filling any suspect areas, and then applying the barrier coat. I will also plan on painting on the bottom paint while the barrier coat is still green. I think the issues arose from the last "barrier coat" because the application process suffered poor technique. There are very different paint application / products from the boot strip to the keel - read inconsistent application process. I hope that I do not see this problem after my efforts here :)
ReplyDelete