Addendum to Gelcoat Repair Article
This is an article from WaveLength Magazine, available in print in North America and globally on the web.
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by Bryan Nystrom
After the Basic Gelcoat Repair article was published in the last issue, I received comments from a couple of readers that I feel are worth passing along. I would like to thank them for their input.
Chris Banner from Seaward Kayaks correctly noted that manufacturer’s recommended mix ratios for gelcoat and hardener should not be exceeded, a point on which I was not clear. Manufacturers often specify a range of acceptable amounts of hardener in order to allow for variations in working temperature. Select the mix ratio that’s most appropriate, but stay within their recommended mix and temperature ranges.
Michael Daly pointed out that there is some risk of exposure to the MEKP hardener when using nitrile gloves. As it turns out, the same is true of latex gloves. Only rubber gloves provide full protection from MEKP. For more details, here is a link to the US EPA article on the subject: www.epa.gov/ dfe/pubs/auto/gloves/. While the amount of MEK product to which one is exposed when doing gelcoat repair is much lower than that in this article (our hands aren’t immersed in it), you should always take appropriate steps to protect yourself when working with potentially toxic chemicals.
Michael also noted that Mylar may stick to gelcoat when used as a release film and suggested that polyethylene, polypropylene or PTFE (Teflon) are less likely to stick, which is true. The release film that came with the gelcoat repair kit I have is Mylar and some sticking does occur. However, it produces a very smooth and shiny surface, which is probably why the gelcoat manufacturer chose it. The other plastics won’t produce quite as smooth a surface, but since you’re going to be sanding and buffing the gelcoat, that’s irrelevant. They’re also much easier to find than Mylar. Remember, release film is only necessary if you’re not using finish gelcoat.
Speaking of which, I recently tried a different type of finish Gelcoat product, Evercoat Gel Paste. It’s much thicker than standard gelcoat, which makes it easier to use on repairs where a thick gelcoat layer is necessary. When filling chips along keels (as in the article), it stays in place and will not run. According to Evercoat, the paste is stronger, but their finish gelcoat produces a better gloss (though I didn’t notice any visual difference). The paste comes only in a neutral color (translucent clear), so you’ll need to add the appropriate tint to it before mixing in the hardener. It seems like a good product to have around. firstname.lastname@example.org