Epoxy storage?

[BroncoSquid]

I have some 5min epoxy I bought 6 months ago. Used it twice, consuming about 10% of it. Slowly the resin in the bottle has started to harden and is all clumpy. The hardener is fine. Is this usual? Storage is on the workbench in the garage. Temp range 85-45 deg. Is there a storage trick of should I buy smaller bottles every 4 months?

[gyrocptr]

Put it in a bath of hot water for a few minutes, and it will usually de-crystallize.

[slipstick]

Epoxy does that a lot. I just zap it in the microwave for a few seconds (20-30 sec....DON'T overdo it ).

Steve

[road king 97]

LOL i have two bottels of 5 min stuff sitting on my bench for 2 years now with no lids at all and used the last of it 2 days ago. joe

[oem flyer]

I believe that exposure to air or at least moist air may be the cause. I had two 4.5 oz bottles do that. One was 5min. the other was 30. I now buy my epoxy in the tandem syringe containers. Once you get the initial air out of them their is nothing but epoxy in the tubes. Haven't had a problem since.

[BroncoSquid]

Thank you for all the replies. I will try heating it up a little. Nothing to loose.

[Rodneh]

I have had epoxy stay usable for well over 5 years and part of that time in a garage that got very hot over the summers. As long as you keep the two components separated, you should not have any problem. Exposure to air has never been a problem with any of mine. As mentioned above, if any of it does crystallise, just immerse it in hot water for a bit. I'd steer away from any microwave as, if you over do it, you can wind up with an almost unclean-able mess.

[slipstick]

Microwave was recommended to me by an adhesives chemist who worked for Ciba-Geigy (manufacturers of Araldite) at the time. But you're right it's only the warmth it needs so if you're feeling nervous hot water will work perfectly well....not quite so rapidly though .

Steve

[road king 97]

Originally Posted by BroncoSquid

Thank you for all the replies. I will try heating it up a little. Nothing to loose.

When putting fiberglass cloth on the middle section of a wing i smear 15 minute epoxy over it then hit it with my covering hot air gun and the epoxy turns to water . I then take a old credit card and wipe the excess off . After you hit it with the gun its drying time goes from 15 min to around 4 . I found out its nice to do it this way because it gets a great bond by soaking into the wood a little and filling the weave. Happy Holidays guys / joe

[kyleservicetech]

Originally Posted by Rodneh

I'd steer away from any microwave as, if you over do it, you can wind up with an almost unclean-able mess.

Yeah, years ago a fellow worker made the mistake of putting some circuit board coating type epoxy resin and hardener into two foam drinking cups, and went home.

That stuff dissolved the foam, and went all over his desk, and onto the floor. They had to replace the desk. (FYI after quite a few more boneheaded things like this, the company replaced that technician!)

[BroncoSquid]

Originally Posted by road king 97

When putting fiberglass cloth on the middle section of a wing i smear 15 minute epoxy over it then hit it with my covering hot air gun and the epoxy turns to water . I then take a old credit card and wipe the excess off . After you hit it with the gun its drying time goes from 15 min to around 4 . I found out its nice to do it this way because it gets a great bond by soaking into the wood a little and filling the weave. Happy Holidays guys / joe

That is a great tip, thanks, I will have to remember that one. Crap... now I have to go out and get a heat gun.

[BroncoSquid]

Originally Posted by kyleservicetech

Yeah, years ago a fellow worker made the mistake of putting some circuit board coating type epoxy resin and hardener into two foam drinking cups, and went home.

I learned that one trying to use Testors plastic model cement on a foam glider 30 years ago.

[road king 97]

Originally Posted by BroncoSquid

That is a great tip, thanks, I will have to remember that one. Crap... now I have to go out and get a heat gun.

Your welcome ,you can also dabb it with foam or tissue to get most the the excess off and to keep it as light as posible but still strong. A heat gun is always great when covering a plane or fixing the covering on one. So to a neat job without and wrinkles i use a trim iron for tight spots a reg iron for the edges and my heat gun to shrink all the middle of my parts . You can also heat up the covering while you pull it around round wing tips for a smooth finish but i use some gloves to pull with so i dont burn my fingers all up ,or two pieces of balsa glued to some plyers to pull with. joe

[kyleservicetech]

Originally Posted by BroncoSquid

That is a great tip, thanks, I will have to remember that one. Crap... now I have to go out and get a heat gun.

Yeah, I've done that for decades, it works very well. You might want to consider proper ventilation doing that though, don't think epoxy fumes are really good for your lungs.

Also, don't try this with 5 minute epoxy, it sets real fast under heat. (Don't ask)

[BroncoSquid]

The hot water bath worked excellent! Just used hot tap water. Mixed better too. Saved me from throwing away perfectly good epoxy. Thanks again.

[xuzme720]

Originally Posted by BroncoSquid

I learned that one trying to use Testors plastic model cement on a foam glider 30 years ago.

I did the same thing, but it was the foam part on a model of one of those Battlestar Galactica's fighters...I can't even remember what they were called now.

[dgholmes59]

The resin is the problem in my experience. It happens to opened and unopened containers. Not sure why. I pulled out a brand new unopened package of Great Planes 30-minute epoxy from my closet this week and the resin had hardened a little. Looks like honey that has crystalized. Unless you want it to get real hot, don't microwave it too long. a few seconds is all it usually takes to liquify it again.

[stevecooper]

I build sailboats (40+years) and use it by the 55 gal drum,, resin has an infinite shelf life and the slow and fast hardener have a shelf life of a minimum of 1 year in a closed container., hope this helps, bubsteve

[FlyWheel]

Originally Posted by road king 97

When putting fiberglass cloth on the middle section of a wing i smear 15 minute epoxy over it then hit it with my covering hot air gun and the epoxy turns to water . I then take a old credit card and wipe the excess off . After you hit it with the gun its drying time goes from 15 min to around 4 . I found out its nice to do it this way because it gets a great bond by soaking into the wood a little and filling the weave. Happy Holidays guys / joe

Nice! I'll have to remember that one.

I have never had any trouble with the resin hardening on it's own, so long as the hardener doesn't touch it - and I mean not even the vapors. What I do is dispence the resin first, seal it's bottle then dispense the hardener and mix it. This insures the resin stays completely uncontaminated.

Originally Posted by xuzme720

I did the same thing, but it was the foam part on a model of one of those Battlestar Galactica's fighters...I can't even remember what they were called now.

Vipers (Colonial) or Raiders (Cylon)