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From: n295vv@aol.com

I have always been mystified by the term, amine blush.  I finally came to the conclusion that it was describing an opaque film on the epoxy and glass sandwiches which we saw when we laid up bids on high-humidity or rainy days.

Although I am a chemist, I never took the time to figure out if this was the amine reacting in some way with the moisture, or whether the mixture was simply hygroscopic and pulling in moisture like a sponge.  I did, however, feel that the moisture seen as an opaque coating was probably going to make a weak bond, and when we saw it, we stopped for the day until we got a drier day.

The fact that some people have seen something when they have fuel heaters in their shops may only indicate that moisture is being built up as a combustion product and the humidity level is too high in the shop.

We did see a change of color over a period of time in the TETA amine hardener which we used.  I concluded it was reacting with the o-rings in the dispenser.  The resevoir of my unit was fairly tightly closed.  Since it takes only 2-3 ppm of impurities to color compounds such as this, I ignored the darkening of the amine hardener.

David Jones, Pecatonica, Illinois

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