Extending shelf life of two part epoxy chemicals

Folks - I've read where you can stretch the pot life of two part
you've already mixed, but my concern is stretching the shelf life of
the individual chemicals once they are open.

I'd like to begin spraying 2 part over some of my smaller fittings.
I'll also have other parts preped so that if I have extra epoxy, I can
use it up ,. however, I'll still be left with more work to do in
three-six months and now, chemicals on the shelf which have been
exposed to air and probably will start to go downhill.

Anyone have suggestions for stretching the shelf life of the
individual chemicals? - Mike

Michael Horowitz wrote:
Folks - I've read where you can stretch the pot life of two part
you've already mixed, but my concern is stretching the shelf life of
the individual chemicals once they are open.

I'd like to begin spraying 2 part over some of my smaller fittings.
I'll also have other parts preped so that if I have extra epoxy, I can
use it up ,. however, I'll still be left with more work to do in
three-six months and now, chemicals on the shelf which have been
exposed to air and probably will start to go downhill.

Anyone have suggestions for stretching the shelf life of the
individual chemicals? - Mike

Keep them in the fridge.

I've done this with proseal and it still works two years after the
expiration date.

On Aug 26, 2:58 pm, Dave wrote:

...
Anyone have suggestions for stretching the shelf life of the
individual chemicals? - Mike

Keep them in the fridge.

I've done this with proseal and it still works two years after the
expiration date.

Keep them well-sealed, especially in the fridge, presuming
that you also keep food in the fridge.

I'm not aware of a specific airborne contamination issue
with epoxy chemicals and food, but, as I recall from my
days as a lab tech, some chemicals kept in a refrigerator
will contaminate some foods that way.

More likely this is an issue with volotile sovents, but
why take a chance? Sealing the containers well is
sure to minimize oxidation and condensation also.

--

FF

I keep my supply of epoxies at room temperature and I believe they will have
a very long shelf life; years if not decades. Of course, for any critical
bonding application, you should do a simple adhesive test to confirm it's
still good before proceeding. Using epoxy before its expiration date is
always the safest course, if not the cheapest.

Keeping some types of epoxy at cold temperature, such as in a refrigerator,
will cause them to crystallize. The crystallization should be reversed by
slowly heating the jug of epoxy in a pan of water until the crystals
dissolve before the epoxy is used.

Dennis Johnson

I keep a gallon tin of West Systems epoxy in my (room temperature) basement,
for general purpose use. It usually lasts about 5 years. I have never
noticed any degradation in performance as it gets older. The only change is
that the hardener gets a mahogany color after a year or so, but it still
works fine.

I've got some cheap ($30/gal on EBay) stuff down there now that's several
years old. It's still clear and works fine.





"Dennis Johnson" wrote in message
. ..
I keep my supply of epoxies at room temperature and I believe they will
have a very long shelf life; years if not decades. Of course, for any
critical bonding application, you should do a simple adhesive test to
confirm it's still good before proceeding. Using epoxy before its
expiration date is always the safest course, if not the cheapest.

Keeping some types of epoxy at cold temperature, such as in a
refrigerator, will cause them to crystallize. The crystallization should
be reversed by slowly heating the jug of epoxy in a pan of water until the
crystals dissolve before the epoxy is used.

Dennis Johnson

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Mike,

Here's a neat trick. When I purchase a new epoxy kit, I always go to
Krogers (or similar low end food market) and get two rubber maid juice
containers with snap top lids. You've probably seen these on the
shelves, you know, the one where the actual top of the container screws
off, and there's a little snap top port off center attached by a loop of
plastic so it can't be lost. Then, I go to my local camera shop and get
one of those cheaper cans of dust off. These are the ones that have a
light, liquefied hydrocarbon under pressure in the can. This hydrocarbon
is heavier than air, and when sprayed into the juice container, will act
as an inerter (I just made that word up) for your epoxy and hardener.

Evan
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In article ,
"Ron Webb" wrote:

I keep a gallon tin of West Systems epoxy in my (room temperature) basement,
for general purpose use. It usually lasts about 5 years. I have never
noticed any degradation in performance as it gets older. The only change is
that the hardener gets a mahogany color after a year or so, but it still
works fine.

I've got some cheap ($30/gal on EBay) stuff down there now that's several
years old. It's still clear and works fine.


That mahogany color is moisture that gets into the hardener. For best
results, heat it to remove the water -- the water reduces strength of
the bonds.

"Orval Fairbairn" wrote in message
news
In article ,
"Ron Webb" wrote:

I keep a gallon tin of West Systems epoxy in my (room temperature) basement,
for general purpose use. It usually lasts about 5 years. I have never
noticed any degradation in performance as it gets older. The only change is
that the hardener gets a mahogany color after a year or so, but it still
works fine.

I've got some cheap ($30/gal on EBay) stuff down there now that's several
years old. It's still clear and works fine.


That mahogany color is moisture that gets into the hardener. For best
results, heat it to remove the water -- the water reduces strength of
the bonds.

What would be a good temperature?

In article ,
"Blueskies" wrote:

"Orval Fairbairn" wrote in message
news
In article ,
"Ron Webb" wrote:

I keep a gallon tin of West Systems epoxy in my (room temperature)
basement,
for general purpose use. It usually lasts about 5 years. I have never
noticed any degradation in performance as it gets older. The only change
is
that the hardener gets a mahogany color after a year or so, but it still
works fine.

I've got some cheap ($30/gal on EBay) stuff down there now that's several
years old. It's still clear and works fine.


That mahogany color is moisture that gets into the hardener. For best
results, heat it to remove the water -- the water reduces strength of
the bonds.

What would be a good temperature?

I'm not sure. A friend who used to work at SRI and researched epoxies
told me about it. I would suggest trying a few samples and temperatures.

I may be the one misunderstanding the OP's request, but I thought he
was asking about 2 part epoxy - Paint - not laminating resin. If so
there isn't much that can be done about extending the shelf life once
the hardner has been opened. Maybe blow some argon from the TIG in
the can and do the same with a zip-lock bag around it for storage?

The last place to store it is in the fridge with food. (been there,
done that, and the fridge made the food taste strange for more than a
year) The stuff reacts with moisture and the innards of a fridge is a
very moist place.
================
Leon McAtee