Extending shelf life of two part epoxy chemicals

[Michael Horowitz]

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

[Dave[_16_]]

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.

[Fred the Red Shirt]

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

[Dennis Johnson]

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

[Ron Webb]

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
>

[Evan Carew]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

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
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.1 (GNU/Linux)

iD8DBQFG0uAGpxCQXwV2bJARAhWkAKDC7f3u9xpjMyovLB9L21 mvnvrSqACgsvT1
urxSKdbG+DA8oHcmNyA5G3o=
=pTAr
-----END PGP SIGNATURE-----

[Orval Fairbairn]

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.

[Blueskies]

"Orval Fairbairn" > wrote in message
...
> 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?

[Orval Fairbairn]

In article >,
"Blueskies" > wrote:

> "Orval Fairbairn" > wrote in message
> ...
> > 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.

[[email protected]]

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

[BobR]

On Aug 28, 1:51 pm, "
> wrote:
> 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

Leon,

You may be the only one who caught the "spraying" part of the original
post. Yes, I believe he was referring to two-part epoxy paint and
everyone was answering for two-part epoxy adheasive and resins. I
don't know of any way to extend the shelf life of two-part epoxy
paints but would like to hear some good answers.

Bob

[Michael Horowitz]

On Tue, 28 Aug 2007 15:05:58 -0700, BobR >
wrote:

>On Aug 28, 1:51 pm, "
> wrote:
>> 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
>
>Leon,
>
>You may be the only one who caught the "spraying" part of the original
>post. Yes, I believe he was referring to two-part epoxy paint and
>everyone was answering for two-part epoxy adheasive and resins. I
>don't know of any way to extend the shelf life of two-part epoxy
>paints but would like to hear some good answers.
>
>Bob
OP here. I was talking about 2 part primer if that make a diff - Mike

[cavelamb himself[_4_]]

Michael Horowitz wrote:
>>
>>You may be the only one who caught the "spraying" part of the original
>>post. Yes, I believe he was referring to two-part epoxy paint and
>>everyone was answering for two-part epoxy adheasive and resins. I
>>don't know of any way to extend the shelf life of two-part epoxy
>>paints but would like to hear some good answers.
>>
>>Bob
>
> OP here. I was talking about 2 part primer if that make a diff - Mike


The temperature thing will work - to a point.

I've put mixed RandoPlate and EpiBond in the friges after mixing so
it wouldn't be sitting around cooking while I was spraying.

I was using a small touch up gun to spray my Tailwind fuselage truss.

When the gun goes empty, pop it open and pour in another load.


Slow it down, yes. Maybe even over night.

But this won't _stop_ the reaction.

Richard

[Orval Fairbairn]

In article >,
cavelamb himself > wrote:

> Michael Horowitz wrote:
> >>
> >>You may be the only one who caught the "spraying" part of the original
> >>post. Yes, I believe he was referring to two-part epoxy paint and
> >>everyone was answering for two-part epoxy adheasive and resins. I
> >>don't know of any way to extend the shelf life of two-part epoxy
> >>paints but would like to hear some good answers.
> >>
> >>Bob
> >
> > OP here. I was talking about 2 part primer if that make a diff - Mike
>
>
> The temperature thing will work - to a point.
>
> I've put mixed RandoPlate and EpiBond in the friges after mixing so
> it wouldn't be sitting around cooking while I was spraying.
>
> I was using a small touch up gun to spray my Tailwind fuselage truss.
>
> When the gun goes empty, pop it open and pour in another load.
>
>
> Slow it down, yes. Maybe even over night.
>
> But this won't _stop_ the reaction.
>
> Richard

Actually, I have saved small amounts of 2-part PPG epoxy primer by
putting it in the freezer. The stuff appears to be usable for a week or
2. It stays liquid and sets up after spraying.

I usually mix it by the partial-teaspoon to do touchup with an airbrush.

[Dave[_16_]]

wrote:
> 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
>
>
I've stored stuff in a fridge that has a limited shelf life for quite a
long time after the life expired.
I'm not talking about messing up food, but keeping the stuff cold where
there is less of a chance of a reaction. if you have a shop fridge with
nothing to hurt, all the better.
I keep my stiff in zip lock bags in a fridge. There isn't much moisture
there due to the temperatures and the "stuff" has less chance to react
to moisture or oxygen because of the temperature.
This could be paint, bread or anything else.
It's basic physics.
As always there's the "it all depends" disclaimer. Nothing is 100%.

[cavelamb himself[_4_]]

Dave wrote:

>>
> I've stored stuff in a fridge that has a limited shelf life for quite a
> long time after the life expired.
> I'm not talking about messing up food, but keeping the stuff cold where
> there is less of a chance of a reaction. if you have a shop fridge with
> nothing to hurt, all the better.
> I keep my stiff in zip lock bags in a fridge. There isn't much moisture
> there due to the temperatures and the "stuff" has less chance to react
> to moisture or oxygen because of the temperature.
> This could be paint, bread or anything else.
> It's basic physics.
> As always there's the "it all depends" disclaimer. Nothing is 100%.


Speaking of zip lock bags... (dreaded thread drift warning!)

I finally tries bagging Bondo!

I did some boat work this last year. Made a mold to form
a pair of fiberglass shelves to fit above the berths.

Aviation composite techniques work fine on boats too!

Making the mold I needed a radius corner on a plywood form.
I've used Bondo for this before - but what a freaking mess to clean up!

So I dumped the Bondo in a reinforced Zip Lock bag (duct tape doubler
over the corner to keep the seams from popping open) and squirted the
bead out like cake decoration.

Then ran a tongue depressor down the bead to form the radius - and it
was DONE.

Came out pretty nice too, I think.

Richard

Pic of plywood plug with finished radius:
http://www.home.earthlink.net/~cavelamb/c18-cab.htm#mold

[Roland Derks]

I've used the same technique on micro/epoxy fillets...didn't try the
duct-tape doulber though....good idea!
Roland


> Making the mold I needed a radius corner on a plywood form.
> I've used Bondo for this before - but what a freaking mess to clean up!
>
> So I dumped the Bondo in a reinforced Zip Lock bag (duct tape doubler
> over the corner to keep the seams from popping open) and squirted the bead
> out like cake decoration.
>
> Then ran a tongue depressor down the bead to form the radius - and it
> was DONE.
>
> Came out pretty nice too, I think.
>
> Richard
>
> Pic of plywood plug with finished radius:
> http://www.home.earthlink.net/~cavelamb/c18-cab.htm#mold

[cavelamb himself[_4_]]

The Doubler made all the difference on something as stiff as Bondo.
Otherwise the bag is likely to split.

I haven't tried it with dry micro yet.
Just haven't had a need yet.

But the bondo bead was so neat it's gotta be worth a try...


Roland Derks wrote:
> I've used the same technique on micro/epoxy fillets...didn't try the
> duct-tape doulber though....good idea!
> Roland
>
>
>
>>Making the mold I needed a radius corner on a plywood form.
>>I've used Bondo for this before - but what a freaking mess to clean up!
>>
>>So I dumped the Bondo in a reinforced Zip Lock bag (duct tape doubler
>>over the corner to keep the seams from popping open) and squirted the bead
>>out like cake decoration.
>>
>>Then ran a tongue depressor down the bead to form the radius - and it
>>was DONE.
>>
>>Came out pretty nice too, I think.
>>
>>Richard
>>
>>Pic of plywood plug with finished radius:
>>http://www.home.earthlink.net/~cavelamb/c18-cab.htm#mold
>
>
>