Ken & all - As explained to me by two technical people from Loctite, which manufactures a wide variety of CA and other adhesives, their Odorless formulation (408 Prism brand Instant Adhesive) accomplishes its odorlessness through a fornulation that has a heavier molecular weight than the odor-ful versions. This weight keeps any fumes from rising to nose level. This is measured as Vapor Pressure. The exposure limit for this formulation is set at the same level as the regular product, which is 0.2ppm TWA. The odor is perceptible at 1-2ppm and irritation occurs at 3-4ppm. Which means, if you can smell it, you're already over the threshold limit. We discussed the difference between allergic response and irritant response, the later being the issue in most cases. Allergic response is found more in skin contact than respiration. While the MSDS advises use of approved respirator, the document's author indicated that such dependance is strongly discouraged for a number of reasons. OSHA regulations require that: - Any respirator, apart from its appropriateness, must be properly fitted, (sorry, no beards allowed :() - Worker must pass physical to confirm ability to tolerate respiratory strain associated with pulling air through filter device - Ambient atmospheric moisture will cause fumes to polymerize on the mask's surface, rapidly restricting the available air flow Bottom line...respirators are not a desirable solution to CA fumes. Only truly advisable method is to generate air exchange. Simple air circulation, as with a fan is NOT advised, since it will distribute the fumes, though, if the space is large enough, and the elapsed time is not prolonged, a fan might work to displace the fumes from the immediate area of deployment. As to the post from Dorothy Bell, I can't address the chemistry, per se, however, the issue of respiratory irritation and the ensuing reactions seems to present itself at lower dosage than would be required to cause any symptoms of cyanide poisoning. The MSDS indicates a concern for the material as an irritant, not as a toxin. Bottom bottom line - Fumeless is better, fresh air is best. Last bottom line - MSDS for Accelerator indicates central nervous system irritant. The residue left after solvent dissolves is, in a word, nasty. I've been way to cavalier in my use of this stuff. David Skolnik Of course, I could be wrong At 11:26 AM 10/4/2005 -0500, you wrote: >I experienced similar symptoms a few years ago. A dealer I did some work >for had me CA the bridge pins on a grand he was rebuilding. I was stuffy >for a few days afterward and didn't make the connection. The second time I >used CA, on another grand bridge, I was plugged solid for a week. That time >I figured it out. Both these jobs used glue he got from Dryburgh, and both >times I was working in a fairly well ventilated room. I guess I'm just a >sensitive guy. I know at least two other people have done the same job in >the same room and suffered no ill effects. I haven't used CA of any sort >since, and I don't plan on any experiments. I haven't been in any >situations where epoxy or other more traditional substances wouldn't work >just as well. (OK, I know lots of you disagree vehemently with that >statement, so don't bother clogging up the list :-). I'm still never using >the stuff again.) > >Regards, >Ken Z. >Dear Friends, > >It is my understanding that "CA glue" = cyanoacrylate glue; > >cyanoacrylate is a molecule which is a chemical combination of the cyano >group and the acryl group; > >once hit with moisture (H2O, or HOH), the molecule breaks down into the >acrylate plus -OH, which makes its little plastic bond or sheath or however >we like to look at it (remember acrylics, for hairbrush handles?); > >and the cyano group gets hydrogenated and becomes our friend hydrogen >cyanide. Yes, the poison that we all know from murder and spy novels. >People are more or less susceptible to it. I don't know whether >susceptibility increases with exposure, either long-term or short-term. But >cyanoacrylate is very reactive, and the "zing" I feel in my lungs and nasal >passages is the chemical reacting with the moisture in my respiratory >tissues. It is possible to add perfumes to the material, I suppose, but CA >is CA. Less cyanide would always be better. > >Just some thoughts from previous employment as a chemistry teacher and a >nurse -- > >Dorrie Bell
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