Trad Gang
Main Boards => The Bowyer's Bench => Topic started by: soy on September 24, 2014, 12:22:00 AM
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Opened up my part b (yellow) to find it has separated and smells like ammonia is it still good to use if I mix it back together?
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I would use it. Mix some up and see how it works for you, let us know how it works out.
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the way you phrase that makes me think that you could have been giggling writing the whole darn thing :laughing: I'll mix some for a test run just thought maybe it is a common thing or an it went bad indicator :dunno:
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So your a glue sniffer huh? :)
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how old is it?---it has a shelf life
I use the tail end of old cans for gluing jigs and household fixes
bow materials are too expensive to be guessing on the glue!
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Here is a answer for you. I googled it.
Epoxy gets its strength when a matrix is formed, which happens because "amine" (NH3) groups on each hardener molecule form strong bonds with "epoxy" groups on each resin molecule. (This part I am sure of; all the rest is a guess.)
When hardener ages, some of the NH3 bonds are broken by water and CO2 in the air. NH4 (ammonia gas) is released (thus the smell), and amine blush molecules are formed.
Now there are fewer NH3 groups to bond with the epoxy groups. Thus, the curing reaction time increases.
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I shut down my business about 6 years ago and from time to time still build a new bow and still using the same smoothon.It has the ammonia smell like that but still works fine.
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Thanks guys....and Roy, I cannot confirm or deny your question :dunno:
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I get that smell everytime I open my smooth-on from the day I bought it practically ... and I went through the whole pint kit in about 6 weeks.
I think it's fine. It's relatively non-critical ratio since it can be mixed from 1:1 to 1:2 hardener to resin. As mentioned, might cure slower, but if you're baking it it's probably irrelevant because a ridiculous amount of curing happens in those 4-8hours.
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Have used smooth on after sitting for well over a year and it has worked fine.
I don't know the chemistry behind the bonding in smooth on - but I do know that amine groups are NH2 that are usually bonded to a carbon in an organic molecule. Ammonia gas is NH3.
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When the brown part starts hardening/drying out on it's own, don't use it. If it mixes different than you are used to... throw it away.