Epoxy glue

[Kittyhawk]

I have a problem with epoxy glue that I really need to resolve.
I use the two pot gel type in mixed tin sizes 350 - 500ml. I only mix very small quantities at a time so the glue should last me for months. Usage is daily and the pots are tightly closed after use. I am very particular to ensure the correct glue/hardener ratios and separate sticks are used in the glue and hardener to avoid cross contamination, and the temperature in my workshop is between 18 - 24 °C.
Brands tried so far are Araldite, Epiglue and Norski.
What happens is across all brands and is always the same.
I open a new pack and the mixed glue behaves as it should - cures to rock hard in around eight hours plus or minus a little depending on temperature.
But after about two months of usage from a new pack and seemingly overnight, the epoxy will cure to the rubbery stage and that's how it stays. There is no further reaction taking place. Exactly the same for the three brands tried so far.
I am a methodical worker and always use the glue in the same manner and in the same place so it's got me beat as to what's going on. The only thing I can think of is perhaps some environmental factors coming into play - but probably clutching at straws. Technical experts on epoxy company helplines offer no advice.

 

[Gordon Tarling]

Apart from trying other brands, all I can suggest at the moment is to buy an epoxy that is in tubes rather than pots and to ensure the caps are put back on as soon as possible after use.

G.

 

[AES]

Don't know the other two brands you mention Kittyhawk, but IME, Araldite is always a No.1 for reliability. I keep mine in the fridge (NOT freezer) and it lasts for AGES, always working and curing as normal. The only downside is that you have to remember that you want to use it about a half hour in advance, otherwise it's so cold it's v difficult to squeeze out of the tube (I've always had Araldite in tubes of various sizes, both the 30 mins quick-cure and the "normal, long-cure" stuff. Never had it in pots).

HTH

 

[eribaMotters]

It sounds like the epoxy is reacting with the air. We know this happens to other liquids such as Danish Oil and Wine, so I'd also say try tubes instead of pots so you keep the air away from the epoxy.
And a wild card, where are you storing the epoxy. I've taken to storing Super Glue in the fridge and found opened tubes now last over 12 months.

Colin

Looks like AES has confirmed by thoughts.

 

[Kittyhawk]

I keep mine in the fridge

HTH

That sounds like trouble. Fun, but trouble.
I know a lady who grabbed a tube of Deep Heat - that's a hot emollient used as a muscle rub - mistaking it for toothpaste. Temporarily did more for her lips than botox ever could.

 

[Kittyhawk]

But trying something else just now with an epoxy test mix. Will advise.

 

[Bingy man]

It’s a bit like that definition of insanity ( not saying your mad btw) but if you keep doing the same thing and getting the same results- change something

 

[Kittyhawk]

It’s a bit like that definition of insanity ( not saying your mad btw) but if you keep doing the same thing and getting the same results- change something

Exactly so. But what?

 

[Bingy man]

I think the clue is in your op- you open the pots and then close them as tightly as possible- surely then the air is trapped inside until your next use - bit like oil based paint or varnish, the air inside the tin reacts with the paint or varnish etc forming an airtight seal . Break the seal and the paint etc is perfect but you have started the process again. The above suggestions of tubes should reduce the air ingress as you are pushing the glue from the back of the tube forcing air out of the end of the tube . Worth a shot ..

 

[Phil Pascoe]

That sounds like trouble. Fun, but trouble.
I know a lady who grabbed a tube of Deep Heat - that's a hot emollient used as a muscle rub - mistaking it for toothpaste. Temporarily did more for her lips than botox ever could.

Good job she didn't mistake it for Anusol.

 

[robgul]

I gave up with any fancy epoxy glues and now stick to ( ) the two-tube syringe stuff from Poundland . . . works a treat with absolute control on quantity and mix ratio. May appear to be more expensive but there's no waste and so far I've had no issues with leaving part used packs weeks at a time.

 

[Terry - Somerset]

Moisture absorption will apparently result in plasticisation.

I assume this is down to humidity - each time the pot is opened, it is exposed until ultimately it degrades. I don't know whether you "enjoy" fairly high humidity - worse when temperatures are high as warm air holds more moisture.

The suggestion for tubes rather than pots seems sensible.

 

[COWS]

Only time I had something similar was when I overdid the hardener. I've since started using West Systems with the pump kits and this has been ok so far. It can be a bit hard to judge ratios when using very small amounts though.

 

[AES]

That sounds like trouble. Fun, but trouble.
I know a lady who grabbed a tube of Deep Heat - that's a hot emollient used as a muscle rub - mistaking it for toothpaste. Temporarily did more for her lips than botox ever could.

OK, I should have said "I keep mine in the fridge LABELLED! And the fridge I use is an old one - a small cheapo bought in the 1980s and kept separately in the work shop. SWMBO knows there's "all sorts of stuff in there", inc cyano as suggested above. Works for me (and her).

 

[Keith 66]

I have used a lot of epoxy over the years mainly West & SP Systems, as far as i can tell both are identical products. It is well known that epoxies have a shortish shelf life, this applies mainly to the hardeners where a colour change happens from honey colour to darker brown, its accompanied by an ammonia type smell.
I have just chucked a two year old pack of Zpoxy as the hardener has gone solid.
A local supplier sells a lot of epoxy that is old stock sometimes years out of date. He swears its ok.
Yet i have heard of at least two expensive failures where a large quantity failed to cure.
I have had one failure using epoxy pitch that was well out of date, cleaning that uncured black gunge off the rudder & keel i had repaired took me two days so a lesson well learned!

 

[Stigmorgan]

I have the same problem with polyurethane fibreglass resin, once open after a time (8 to 12 months) the bottle of resin cures even without hardener, the lid can be a pita to get off even after a month if I forget to clean the residue off, for which I use cheap nail varnish remover from Poundland

 

[NFav]

In the motor trade 2 pack stuff is used a lot, and generally its the hardener that goes 'stale'.
I've used a bit of filler from a tin was started years ago, but with fresh hardener it still works well.

 

[thetyreman]

I put mine in an airtight bag, seems to help prevent it going off.

 

[Jameshow]

That sounds like trouble. Fun, but trouble.
I know a lady who grabbed a tube of Deep Heat - that's a hot emollient used as a muscle rub - mistaking it for toothpaste. Temporarily did more for her lips than botox ever could.

Once did that for a groin strain after a hike, I was jumping round the campsite!!

 

[D_W]

in the states, we buy small amounts like that in separate plastic squeeze bottles. Over time, the material will gel a little bit but a very small amount of heating, even +15C or something will make it flow again.

I only use epoxy for handles, and not always the same type. the last 500ml pair that I have (roughly that amount) lasted more than five years, though when I was going to use it, I did have to put the bottles upside down somewhere warm because the flow had decreased and would only flow freely in summer. It always dried hard.

Some of the 5 minute version is literally holding a very heavy sink up in my kitchen because when I installed the sink, i couldn't locate the new epoxy I'd bought to install it and I had limited time with my "installer" (my dad) helping. it's held for probably about four years so far.

I like the plastic bottles better than tubes because as soon as something gets a little slow in tubes, you often start to increase force to get it out and the result is usually splitting the tube. contact cement here is almost as cheap in a pack of 5 as it is two separate. I make the mistake of having several open at once when one is misplaced, and almost guaranteed, I will fight it (out of thrift) until the wrong end of the tube splits.