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Post by krazydiamond on Jul 12, 2005 11:12:50 GMT -5
i started experiencing glue failure with some (over a year) old 330 epoxy. at first i thought i didn't mix it well enough, with it being clear it's hard to tell if it's mixed properly.
then i blamed myself for getting the proportions wrong.
still more failures, wasn't drying hard at all, so i blamed the humidity!!
finally i said, well, you can imagine the blue air, and i tossed out the old stuff, opened up a brand new package and it dried clear and hard (LIKE IT'S SUPPOSED TOO!).
anyone got a comment to share on this?
KD
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themax
having dreams about rocks
Member since April 2005
Posts: 61
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Post by themax on Jul 12, 2005 13:17:54 GMT -5
KD,
I think epoxy must have a "shelf life." I don't remember exactly which brand or type of epoxy I was using but it was a two part, clear drying epoxy that was supposed to be effective on all types of surfaces including rock, wood, glass etc. One time it worked like a champ. Several months later I mixed another batch and it never set up. I went through the same gyrations you did; mixed more, nothing. Squeezed out a bunch attempting to get to "the fresh stuff" and mixed a bigger batch with the same ineffective result. I too just threw the old tube out and got new which again worked as advertised. At the time I remember looking at the packaging to see if there were an expiration date and didn't find one. I suspect once either or both chemical is exposed to air and humidity it effects both substances. At least that's my two cents.
Max
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joanna
spending too much on rocks
Member since November 2004
Posts: 385
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Post by joanna on Jul 12, 2005 15:06:02 GMT -5
Some glues have a temperature range they should be stored at. Sometimes it will be listed on the containers, sometimes not. I believe with my wood glues I've read that it shouldn't be stored under 50 degrees (not sure of the high end temperature - maybe that doesn't matter as much).
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Post by Alice on Jul 12, 2005 22:47:34 GMT -5
I find that if you put in more of the "non-clear" stuff then the "clear" runny stuff, I get better results. If you put too much runny stuff, it won't dry.
the non-clear stuff sure is a bugger to get out of the tube though, but worth it in the end.
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MichiganRocks
starting to spend too much on rocks
"I wasn't born to follow."
Member since April 2007
Posts: 154
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Post by MichiganRocks on Jul 13, 2005 7:04:06 GMT -5
Most adhesives do have a shelf life, and it's normally a year. Like Joanna said, keeping it in a refrigerator will normally keep it active longer. Heat acts as a catalyst and these hot summer days can spell the end of a tube of epoxy.
The hardener that is added to the resin in epoxy is only used to accelerate the setting process to a usefully short time, however; the resin will take a set without the hardener. It just takes longer. After a year there has been enough chemical reaction occur in the resin that too high a percentage has already undergone change and will no longer act as an effective adhesive. It's kind of like if you took epoxy that has set up and ground it up into a very fine powder and then made a paste. It might look like the orginal epoxy resin, but it won't act like resin since it has already been transformed at the molecular level.
By the way, most superglues undergo a similar process.
Ron
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stefan
Cave Dweller
Member since January 2005
Posts: 14,113
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Post by stefan on Jul 13, 2005 9:21:09 GMT -5
I have some unopened Epoxy (for x-country ski repair) that is over 5 years old- stored in a coll dry dark place, and is as good as new- But I also had some that was opened- used once then reclosed- stored in the same location- would not hold for a damn!
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MichiganRocks
starting to spend too much on rocks
"I wasn't born to follow."
Member since April 2007
Posts: 154
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Post by MichiganRocks on Jul 13, 2005 13:14:32 GMT -5
Once it's been exposed to the air, the clock starts ticking.
Ron
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stefan
Cave Dweller
Member since January 2005
Posts: 14,113
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Post by stefan on Jul 13, 2005 13:36:38 GMT -5
Tick Tick Tick- KD Better start using that stuff up faster!!!!
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Post by Tweetiepy on Jul 13, 2005 13:39:54 GMT -5
I have a bike repair kit where the glue was used once and then KAPUT nothing left in the tube! - but I bought another repair kit at the dollar store and will be keeping this one - cuz I know I'm gonna need it
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