Epoxy Reconsidered

My last post was, I admit, a bit negative and, frankly, not really in character. Any essay titled “Why I Hate Boatbuilding” requires further explanation.

This is sawdust, not epoxy, but you get the idea. I'm smiling here, but I wasn't so happy after sanding the epoxy.

You may recall that I was reacting to a day spent sanding (or “fairing” to use the appropriate terminology) the epoxy-coated hull. Grinding away the uneven surface with a belt sander exposed me to a nasty cloud of epoxy dust, which is both unpleasant and unhealthy. I kept reassuring myself that I was taking extra precaution by using a respirator, but I still developed a persistent cough that lasted for several days.

I was ready to swear off epoxy and fiberglass forever and even now I am aggressively investigating building techniques that limit the use of epoxy. Who knows, my next boat might be a traditionally planked cruiser. More likely, it will simply be another plywood boat, but one that is held together with non-toxic glue, such as Titebond III, and no more fiberglass than necessary to cover the seams.

But I still need to finish this boat, which means that I need to make at least temporary peace with epoxy. Happily, I discovered several strategies that significantly lessen the amount of dust in the air.

First, and most obviously, I needed to get the dust out of the garage. I moved the boat closer to the double garage doors and positioned a fan behind the boat so that, in theory, dust would blow out and disappear. This helped, at least psychologically, as did my decision to keep the respirator on even after I finished sanding. I didn’t want to breathe in particles that lingered in the air.

But what most helped were changes in how I applied epoxy and how I sanded it down. New to the process of fiberglassing, I applied thick and uneven coats to the underside, which simply ended up as dust when I ground it down with the belt sander. But as my skills improved, I learned to apply thin, even coats that require less sanding. That was a major step forward.

Finally, and most recently, I discovered the advantages of wet sanding. This is not really part of my repertoire as a woodworker (you don’t wet sand a cherry table, for example), but a passing reference to this technique by an online correspondent made me curious and I immediately went to the garage, dipped some 80 grit sandpaper in water and discovered that it’s possible to fair the hull without making any dust at all. The disadvantage is that I need to sand by hand (for god’s sake, don’t dunk your belt sander in a bucket), but that’s small price to pay for peace of mind and, besides, I don’t like belt sanders anyway.

So the end of the story is that I no longer worry so much about epoxy and I think I can finish the project without having a visit by the EPA. But I still feel that epoxy and fiberglass—which are treated as necessary and magical ingredients in boat building—deserve to be treated with caution and used sparingly. Time and time again, I see builders deride old or nontoxic techniques for assembling and waterproofing boats. “Don’t use [fill in the blank]; epoxy is better!” is the common refrain. And in some ways, they are right. It’s the strongest, most waterproof adhesive available, as far as I know. But there are always other factors worth considering when choosing glues and coverings—ranging from cost (epoxy is more expensive than other kinds of glues) to environmental considerations (why do I recycle plastic bags in the house, but build a plastic-covered boat in the garage?) to justifiable worries about health (people can develop allergic reactions to uncured epoxy and dust is bad for the lungs).

And, finally, there are aesthetic considerations. At the very least, it’s an unpleasant substance to work with—a material to be tolerated more than enjoyed as it fills the air with acrid fumes and sticks to the skin with irritating tenacity. And anything that takes joy away from a hobby deserves scrutiny.