Epoxy Resin

Morning

Got some epoxy thats not hardening. Its past its expiry date now. Since I've got rather a lot of this stuff, is there any way to get it to set? Or is it a bin job.

cheers, NT

Reply to
meow2222
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best binned. From experience even if you do get it to set it sometimes turns out lumpy with some bits still soft

Reply to
Alang

Its now poxy resin :-)

Reply to
The Medway Handyman

You could try increasing the dosage of the hardener to the resin, see if that helps. Alternatively warm it up - that usually make it cure faster, though you may find the strength of the joint goes down.

Reply to
pete

Just a thought, from ignorance not knowledge, is it the hardener, the resin or both that are old? If the hardener is old, maybe it would work (better) with just new hardener?

Reply to
Rod

In message , snipped-for-privacy@care2.com writes

I've used a lot of SP Systems and West epoxy, and have only had trouble with batches that have been allowed to stand in a freezing shed all winter. Some of the oldest 'sets' were several years past the expiry date. I used them for less critical jobs, but they still worked fine.

The stuff that had frozen had turned lumpy and with an almost semolina type look, so it was obviously a bin job.

I'm not sure that altering the ratio will help at all. If I understand correctly, the hardener isn't an accelerator like in 'fibreglass resin', but mixes with the resin to form a different chemical.

I've always had to run the fine line between thermal runaway and smoke from the mixing pot and the cold preventing the correct reaction.

Reply to
Bill

Indeed not. Epoxy has a hardener, polyester uses a catalyst. _Good_ epoxy has a useful life (for non-critical applications) that lasts until the resin is obviously physically changed. Polyester has a very limited life for the catalyst, but that can be replaced quite cheaply. Some of the rabid epoxies suffer from hardener shelflife, but general they last indefinitely as long as storage is good, and if they've failed it's because they were mis-stored and that's an end of it.

Reply to
Andy Dingley

Resin and hardener are both about 5 yrs old, I'm going to see if heat works, but am not very optimistic.

thanks all NT

Reply to
meow2222

It's nasty stuff too - last time I used some it took three men to hold the tube down while I unscrewed the top.

Regards,

Reply to
Stephen Howard

Heat and thorough mixing should work.

DO NOT VARY PROPORTIONS.

The hardener is _not_ a catalyst. If that doesn't work chuck it.

Reply to
The Natural Philosopher

OK, I took a magnifying glass to it, and despite going through a self mixing nozzle it turns out the stuff is clearly not properly mixed, so mystery now solved.

However, that doesnt entirely solve the problem. Once the old stuff is cleared out of the 3.5" deep 8mm hole, and once the epoxy has been hand mixed... how the heck do I get it to fill the hole? I cant figure out how to get it down a standard non-mix nozzle. Perhapt attach a rubble bag and use like an icing applicator?

NT

Reply to
meow2222

Heat is your only hope..not sure why you are using epoxy to fill a hole like that anyway..or what a self mixing nozzle is?

All epoxy needs a huge amount of stirring to get the two parts well distributed..no nozzle can do that.

If its one of those twin syringe things, that isn't a self mixing nozzle, thats simply a way to make sure you have the correct ratio of elements: thorough mixing is still required.

And if the stuff ah s gone crystaline through age, warm or hot air is the best way to mix it.

And if I wanted to fill a 3.5" 8mm hole, Id get a ruler that works in the same units, and use car body filler anyway ;-)

Reply to
The Natural Philosopher

I've done that (the bag thing) before, with success.

As an observation, it sounds like you're using industrial quantites here, not merely the small squeeze of Araldite that most DIY-ers use. Have you considered adding a filler powder to the resin, rather than just using it "neat"? Apart from reducing the quantity of resin required (and therefore the amount of heat it produces as it cures), the correct filler will also stop cracks propogating through the body of the resin and produces a more durable and workable bulk as a result.

Reply to
pete

Although heat is likely to encourage curing, if it's at the stage where _only_ heat is getting it to cure, then the end result is likely to be weak. Might still work for gap filling, but don't rely on it.

Reply to
Andy Dingley

And it can give you a terrible bite :-)

Reply to
fictitious

In message , snipped-for-privacy@care2.com writes

For my boat-type uses, I use plastic syringes to measure out the quantities into whatever plastic throwaway small bowl that we have recently eaten the contents of. I think some of them are supermarket porridge. Mix well. The bowl needs to be reasonably shallow to reduce the risk of thermal runaway. Then use a filler. I've used glass bubbles to give more bulk, colloidal silica to give stiffness and, most often, milled wood fibres, which I managed to get a bulk lot of some years ago. Small particle sawdust is probably easier to come by and looks less like an exotic mind-bender if ever one is entertained by the constabulary whilst on lawful business.

I'd also use a syringe and a bit of pipe to fill the hole. Wear latex gloves and don't get an itchy nose until the job is finished.

Reply to
Bill

no. Heat makes it less sticky and easier to mix, and helps dissolve crystals in it.

I generally use a heatgun or the Aga on epoxy anyway as a matter of course.

But the point was to get decent mixing.

If he played a gun on what was in the hole now, and stirred it..

for example.

Reply to
The Natural Philosopher

I'm always scrupulous about making sure the two are well mixed (as my old Dad taught me :-). I've never heard of a self mixing nozzle, and I'm highly skeptical that such a thing exists.

Reply to
Gib Bogle

Is the hole vertical? If so gravity is your friend. Even without heating the epoxy I use is quite runny, and I'm told that a bit of heating makes it more so.

Reply to
Gib Bogle

In message , Gib Bogle writes

I don't want to keep popping up and sounding too anal about this, but heat can make epoxy do strange things. Thermal runaway can be quite frightening, as the container starts smoking and reaches very high temperatures. The fumes given off, especially if you are becoming at all sensitised to epoxy, can be dreadful. A heat gun can make a mess of epoxy as it sets. On boat keels out in the cold, I've used a pair of those rechargeable 10-million (or whatever) candlepower torches right up close to the repair job to keep it warm.

For filling a hole, I'd definitely mix some sort of filler into the epoxy to make it a stiff runny consistency like semolina, maybe. Fine sawdust can work very well. Things like Araldite have fillers in already.

Reply to
Bill

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