# Epoxy -will it harden



## snowdog (Jul 1, 2007)

I messed up and was not paying attention to detail and did not use enough hardener in the mix. Will it ever harden? 
It was approximately:
1 to .70 mix 
Epoxy to Hardener:


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## patron (Apr 2, 2009)

with any hardener at all
it should be fine

i have had to wait for 4-5 days sometimes
as i just eyeball the mix


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## snowdog (Jul 1, 2007)

I dislike when I mess up something so simple, no fool like an old fool. At least I usually only make a mistake once, but there are so many things that can go wrong that I always find another thing to mess up. At least I do not have to make the same mistake twice <laugh> to keep making mistakes.


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## SCR0LL3R (May 28, 2010)

I don't speak from personal experience but it is my understanding that epoxy is a 2-part mixture with each molecule needing a corresponding molecule of hardener to bond with chemically in order for it to harden. It's not like a resin/catalyst reaction like with fiberglass where less catalyst just slows down the hardening process.


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## CharlieM1958 (Nov 7, 2006)

Once you pass 50, everything takes longer to get hard.


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## degoose (Mar 20, 2009)

Charlie, now you tell me…


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## snowdog (Jul 1, 2007)

That is funny Charlie but I thought it was the longevity of the system that took a toll after 50


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## MrRon (Jul 9, 2009)

Keith, There are many different mix combinations. They are formulated by the manufacturer to suit different requirements; some for strength, some for speed, some for convenience (2:1).


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## mafe (Dec 10, 2009)

Pls tell us if it did.
I have only once tried that it was impossible, but I think the product was bad…
Otherwise time solves it, but I suspect it will not be as strong.
Best thoughts,
Mads


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## shipwright (Sep 27, 2010)

Kieth is right. Epoxies (true epoxies, you never know what someone may market as an epoxy) are sold in two parts because the are two reagents in a chemical reaction that will form a polymer. When mixed they will react and form new molecules in what ever ratio is required (like the 2:1 ratio for hydrogen and oxygen to make water)

If, when all the available partner molecules for one reagent are consumed, there are still molecules of one or the other in the mix they will prevent the material from achieving it's potential in hardness, strength, etc.

These effects can be minimal with some cases and catastrophic in others. A few spare molecules is no big deal but if you are dealing with a 5:1 mix and you mix it 1:1 you will have a big sticky mess to clean up.

This is completely different than catalyst reactions like polyester where all the reagents are already present in the resin but won't react without the presence of a catalyst (MEK for polyester). In these reactions the more catalyst you add the faster they will react. The only way you can speed up epoxy is with heat.


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## mafe (Dec 10, 2009)

Not too hot!
You can acually micowave epoxy joints and take them apart, I do that in my knife making.
Also I make it more easy floading with heat before it dry up, but don't try this with the fast version.
Best thoughts,
Mads


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## WoodNuts (Apr 30, 2010)

Hey Charlie, he didn't ask how to push a rope.


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## snowdog (Jul 1, 2007)

The epoxy was some no named brand I got at a local hobby shop to glue my air plane wings together. It has hardened after 4 days to the point that I feel confident in its ability to stay together <laugh> There is a carbon fiber tube adding rigidity to the wing so I will test fly it this week when the weather is a bit nicer and see if I can crash it 

Here is a pic of the plane , and no that is not me, just a pic from the hobby shop. (http://www.horizonhobby.com/Products/Default.aspx?ProdID=EFL2725)


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