Questions: Toxicity of Odorless Superglue

by Bill Hunter

Originally published in American Lutherie #82, 2005 and Big Red Book of American Lutherie Volume Seven, 2015

Ralph from Austin, Texas asks:

I recently read on a luthier e-mail list about a guy using odorless cyanoacrylate glue for filler. The brand he uses is by Satellite City, maker of Hot Stuff™ and UFO™, which stands for “user-friendly odorless.” I know from experience that vapors from CA glue are not friendly to the eyes or to the respiratory system. My question is: if it has no scent and you don’t have any skin exposure, does this mean it’s rendered totally nontoxic or nonirritating? The bigger question is: how are products made odorless? Are there just blocking agents so that we are unable to detect them, but they’re still there, and therefore still irritating or toxic?

Bill Hunter of Simi Valley, California, cofounder of Satellite City, answers:

“Toxic,” in general implies a lasting or long-term harmful effect. Cyanoacrylate adhesives are not toxic except to those who are allergic to them. The same could be said of milk, peanuts, and grains. “Irritating” is comparable to the feeling one gets in the eyes and nose when dicing onions. The scent is not what irritates the eyes, nose, and throat, it’s the fumes. And, of course, if the fumes are masked, a product can give the unrealistic impression that there will be no irritation. In fact, the scent of many chemicals is a good gauge by which to judge exposure. If, on the other hand, there is no scent because there are no fumes, you have the best possible working conditions. Hot Stuff “UFO” instant adhesives have been relied on by folks who have allergic reactions to typical cyanoacrylates since 1988. Many of these people can’t be in the same room where an instant glue is being used without a violent reaction. No problem with “UFO.” It’s the only CA they can use. Regarding skin exposure: Skin exposure, even for typical cyanoacrylates, is not a consideration for 99.99% of users, and in thirty-five years, I have never, ever heard of anyone being bothered in any way by skin exposure to “UFO.”

Note: Mr. Hunter also sent me the MSDS on CA glues, which didn’t help me understand. I tried to follow-up Mr. Hunter’s answer and he repeated the above information. I’d like to hear from some of you with sensitivities to the regular stuff and perhaps others who understand the chemical lingo. A product so seemingly integral and essential to modern lutherie certainly deserves a little scrutiny.