This post is a follow up to my first article on blister repair using West Six/10 Epoxy. The initial process was very easy and convenient, but I've now travelled a bit farther down the path and an update is warranted.
The first thing I noticed was that most of the blisters I repaired were not fully filled by the initial coat. I will be the first to admit that this could be a lack of some skill in application on my part. That being said, I have no trouble using fairing compound in other places on my boat, so I don't think this is the case. I believe that the Six/10 is simply a bit more than I'd normally mix fairing compound, and as a result it depressed more easily when the spreader passes by.
This isn't really a failure of the product, as it doesn't indicate a lack of barrier coating or adhesion. I had the impression that most blisters would need a single coat from the Epoxyworks article. Had the article said I should plan on a re-coat in most cases, then I'd have no problem. Again, this could just be me screwing something up. I don't know... What I do know is that I'm going to spreading a second layer, and trying to focus on making it a bit thicker than needed so I don't need a third coat.
The second thing I observed today is purely on my shoulders as it's noted in the article. Sanding this stuff is brutal. I mean, it chewed through sanding sheets at an unbelievable rate. So when you apply Six/10 make sure the areas surrounding the blister are scraped as thin as possible. I had a few places where the listers were dense which I didn't pay much attention to, and that was definitely a mistake. The epoxy ended up like a titanium barrier coat over a square foot. I suggest using a random orbit sander, not a traditional palm sander, and make sure you use the good no-clog paper for it. Don't screw around with this one.
Another boater stopped by to ask me why I was repairing the blisters this way. He had far more experience than I did, and told me that the only way he's seen blisters repaired with success is by stripping the bottom paint, fairing them, and then then applying a new barrier then bottom coating. It's sometimes easy to doubt what I'm doing since I have no experience and am surrounded by people who have been sailing their whole lives. I certainly respect his concern and advice.
I think there's good rationale behind the Six/10 method, and good rationale to the traditional method. Blisters have been a black art for so long, and a failed blister job means a laborious and costly re-do. As such, I think blister repair methods have considerable inertia. I'm going to stay the course, and keep an open mind. If I'm wrong, then I'll be doing it over again next year. It would be depressing, but I can live with this as a worst-case.
My next step is to finish the 1/3 of the hull on the starboard side. I will focus on trying to make the epoxy site proud of the blister hole, and on minimizing unnecessary epoxy thickness. Seemingly contradictory goals... I'll post a final article as soon as I complete the job.
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