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paul wiser
05-05-2012, 11:17 PM
anybody have any input on ca toxicity if it used on cutting boards? i inlay some of my boards and fill them with crushed gemstones and epoxy. ca would be much easier to sand. the epoxy tends to melt when i try to sand it level! any suggestions?? thank you :confused::confused::confused:

Ken Fitzgerald
05-05-2012, 11:52 PM
According to Wikipedia..... "There is no singular measurement of toxicity for all cyanoacrylate adhesives as there is a wide variety of adhesives that contain various cyanoacrylate formulations."

Sid Matheny
05-05-2012, 11:57 PM
As long as you let it cure completely to the point you can not smell the CA, you will not have any problems. IMHO.


Sid

John Coloccia
05-06-2012, 1:11 AM
File the epoxy level with a coarse, single cut file. It will flatten the epoxy and skip over the wood. Ditto for anything hard that you put into wood....metal, shell, stone, etc. File first and leave the sandpaper for last.

Goes for CA too.

If you stay with epoxy, switch to a finishing or fiberglass resin. It will sand much easier. ZPoxy finishing resin is a favorite. So is West Systems. ZPoxy is a dream to work with, though. Pick some up and try it out on scrap with a file.

Bob Fraser
05-06-2012, 2:05 AM
it has documented usage for closing wounds in humans (for many years, now), I don't spoze it would be THAT toxic given your application.
bob

Guy Belleman
05-06-2012, 2:41 AM
Lots of MSDSs out there for the super glue formulas. Toxicity by ingestion (LD50) on one MSDS is published as 12.2 CC/KG, with a density of 1.05. Which means that for a 150 lb person (68Kg) that it would take about 832 CC, or 792 grams (1.7 lbs) to give a 50% chance of death. In other words, the toxicity is really low.
MSDS at http://www.biosci.ohio-state.edu/~safety/MSDS/SUPER%20GLUE.htm

To give a little perspective on this, the toxic amount of peanut butter is about 5 CC/Kg.

Perry Holbrook
05-06-2012, 8:39 AM
A few years ago I spent the afternoon at the medical clinic due to breathing CA fumes. In my case I had used it to tack some small steel plates together before welding. The welding burned the CA, producing fumes that as it turned out were very bad for me. Apparently I had a high sensitivity to it. I can't use it any more except in very low amounts and outside. If I sand a wood joint that has been glued with CA, I can still have some minor breathing issues.

Perry

William Payer
05-06-2012, 10:50 AM
it has documented usage for closing wounds in humans (for many years, now), I don't spoze it would be THAT toxic given your application.
bob

Medical grade CA is a different chemical composition than the formulations used as general purpose adhesives today. I would expect then general purpose formulations use less costly ( and likely more toxic) ingredients .
I would check out the adhesives MSDS before using.

ian maybury
05-06-2012, 11:46 AM
I worked for some years on CA development projects Paul. The stuff is actually pretty safe by all accounts, it's more or less inert once cured barring heating/burning etc. The latter risks creating all sorts of by products, and while none I think is very toxic they can be a bit nasty. Sanding will of course create dust that could be problematical if inhaled as in the case of any other broadly inert dust.

Whatever problems do arise seem to be as a result of the fact that the monomer (the basic uncured resin) is quite volatile at room temperature. The blooming effects you get with it on polished surfaces are the result of this air borne vapour curing where you don't want it. it's also the basis of its use in fingerprint kits.

Even in liquid form it's not reckoned to be nasty per se, but it does seem that the vapour can trigger irritation and other reactions in the very odd person, and that if the latter happens (you get sensitised) the likelihood is that this will happen on renewed contact in future. (you can actually get sensitised to almost anything e.g. soap ingredients if it enters the body and the immune system types the particular compound)

It's common enough apart from any allergic reaction for more heavily exposed people to experience sore throats and eyes too due to simple tissue irritation - not surprising since the vapour presumably results in tiny particles attached to tissue when it cures on contact. Used in industry the H&S people seem to require extraction at the point of work, but no more.

My personal view is that like most chemicals there's the possibility of unanticipated issues, and that it's better not to breathe it - but that extraction as above should avoid most problems.

A more basic issue is perhaps that while the cured resin is itself pretty much waterproof (not totally), the electrostatic/polar/wetting aspect of the bond is unzipped on exposure to water. This is especially an issue on smooth surfaces that rely on wetting for adhesion - where the adhesive cannot penetrate the substrates as on e.g. wood to create mechanical interlocking as well.

It may be for that reason that it's not ideal for use on a cutting board that may be exposed to water or will be washed - definitely not on impervious surfaces anyway. it's going to struggle to cure on mildly acidic surfaces too, although an activator can often overcome that....

ian

Alan Lightstone
05-06-2012, 1:18 PM
FWIW, I watch it being used every day to close surgical wounds.

Bruce Volden
05-06-2012, 8:13 PM
I've never had problems with the toxic part other than it being an irritant (burning of eyes nose etc), but I couldn't imagine it for use on a cutting board. IIRC it is water soluble (after time it breaks down). I too use it with inlay in my laser business and have been using it for better than 15 years. $.02 from me.

Bruce

Steve Meliza
05-07-2012, 11:12 AM
I'm one of those very odd people that has developed a sensitivity to CA (I have no other alergies), and I know of plenty others. At one point I could use it all I wanted, then one day I got a nasty cold, or so I thought. It took months of being sick followed by brief periods of being well to finally match the pattern and discover the source. I was so miserable at that point that every opened bottle of CA went into the trash and a week later I was better and I've never looked back. Now days if I can smell CA then I'm probably going to pay for it later, but it has been several weeks since my last exposure I might be fine.

The stuff is nasty even if you're not sensitive to it now, the dust is bad for you, and I've never heard of CA being praised for its ability to be sanded well so I would stick to a quality epoxy.