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When Epoxy Does Not Set....


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I was using some epoxy to glue up some pieces and patch some holes in a template and for some reason the glue did not set properly. It still feels sticky. I mixed it half and half from the bottle but it still sticks.

any ideas on how to get to to finally set? heat gun? Time?

Thanks,

Derek

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If it's not dry within an hour, it's probably toast and will not dry at all.

The same thing has happened to me when I tried to use just a portion of the goods.

The only way I have found to get 100% results is to completely use both tubes all at once unfortunately.

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Usually that happens when you don't get enough hardener mixed in (its happened to me from those side-by-side syrenge tubes before). I would let it set to see if it cures. Heat probably wouldn't be a good idea since it softens epoxy.

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Drak's correct, your mixture didn't work probably because you didn't get equal amounts of mixture. I always just mix it all just to be certain, but then again, it can be a waste if you was planning on using only a little. HINT: If it's the two tube with a push down in the middle, then push down even pressured over something disposable until both sides dispense, that will get all the air out that sometimes causes problems, then you can press down into a mixture cup with the same method to get an even mixture before mixing. That's just something that has worked for me, may not for you.

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I've had the exact opposite happen to me. If I put a bit more hardener, it didn't totally harden and remained rubbery. If I put a bit less hardener, it became nice and hard. And no, I didn't confuse the two tubes unless they were mislabeled. Make 2 small trial batches, one with more hardener and one with less, and see how your particular epoxy hardens.

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Epoxy is finicky. It is probably as Drak said, not enough hardener or not mixed enough. I use the West System epoxy with the precision pumps that meter out exact amounts for the mix. You can get small or large containers and as long as the pumps are the right ones you get a perfect mix each time. I also make sure to mix up a little more than I need to ensure there is enough to get a good mix. Check out the West System site, there is great info there. They say either too much or too little hardener will result in uncured epoxy.

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Try spraying some acetone over the epoxy from a regular atomizer spray bottle. I've had epoxies that won't set from being to old in the model airplane hobby, and 90% of the time, spraying a little acetone over it and letting it evaporate has cured it. The other thing you can try is heat it with a heat gun until it gets sticky, then leave it overnight, it will most likely cure hard after that.

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Please check back in and tell us if it worked or not because...

...I use Acetone to thin my epoxy (to make it runnier), and I have found if you use too much (very easy too) ...it will not cure.

Acetone -slows down- the curing process with epoxy...I have used it successfully numerous times on purpose, but the more you use, the slower the curing time, so I find it rather hard to believe, based on my experience with it, that wiping Acetone on a piece of epoxy that is already having a hard time curing will do anything at all to help 'cure' your problem ( :D ), especially if your problem is that you got the mixture wrong to begin with.

If you look at how epoxy actually cures, I also find it hard to believe that if you got the mixture wrong to begin with, that heat will do much of anything either.

But I will wait and see what results you report back. :D

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Well, I've used it many times with epoxy finishing resins. You have to spray it on in a mist, if you wipe it, you'll probably just make a mess. When you spray it, I think what it does is bites in and evaporates pretty fast taking some of the amines with it that make the epoxy cure. It's true that if you mix it in it thins epoxy, I don't recommend this if you are going after a structural joint though as it weakens it somewhat too. I know for sure this trick works with Hysol epoxy as well as West systems, haven't tried it with the regular modelling epoxy, but it's all based on the same organic amines so I think it should work fine. Heat is a by product of the cure, epoxy creates heat in its chemical reaction, adding heat to it will advance the cure in the same way that baking a paint finish speeds up and creates a more thorough cure with 2 part automotive paints.

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Yes, I absolutely agree that heat is a byproduct of the curing process, and that heat would absolutely speed up the cure, just as in speeding up the cure of any typical finish, my reservation was that if the mixture was wrong -to begin with-, whether the heat would have any effect on it as the 'mix' was possibly wrong from the start, if you follow...but I will sit and wait for Derek's results.

Anbd maybe the amount makes a difference too, if he's just doing a tiny hole maybe it will work...my areas were of a much larger proportion, usually filling in -big- holes in Buckeye Burls.

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ok so I bought some acetone.

Here is what I did.

I had a small hole in a humbucker template that I wanted to plug and redo. So I mixed the glue obviously not right and it was still sticky.

I took the acetone in a rag and wet it once, twice three times a lady.

It dried up the sticky ness but.... it also gave some drying shrinkage marks. So its good for drying/harding stuff that does not matter, though I am not so sure I would do this on a buckeye burl top unless I tested in in a small portion.

The epoxy dried hard and seems to be hard as if it dried by itself. I applied the acetone heavily by the third time.

-Derek

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