Need some epoxy help

I have been using epoxy for repairs and scratches on our clear coat Kevlar boats for the past twenty years, and this is the first time I have had this problem.

I did some touch up two days ago on some scratches and evidently screwed up on my mixture.

Today, two days later the places I did are still tacky.

Has any one every had this problem, and what is the fix?

Would putting it out in the hot sun help?

Jack L

Usually low temperatures keep epoxy from curing properly. If you have the right materials for your temperatures, did you measure correctly? The only other normal problem is mixing enough.

Usually low temperatures keep epoxy from curing properly. If you have the right materials for your temperatures, did you measure correctly? The only other normal problem is mixing enough.

Old hardener
can also cause this, as well as incomplete mixing. I feel sure with your experience it was mixed well. I think it has been warm enough up your way if day time temps are over 70F.

Yes, put it out for a day and see …
what happens. If it goes through heat and still not hard, then dig it out Jack. Sorry.

I’ll try that tomorrow, but …
I don’t think it will work, since it is hotter then the hinges of hades in the shop where it is.

When you say “dig it out”: How is that done ?

Jack L

I would reduce the possibilities to two.
One is that your mixture was off. Two was that there was some adulterant in the resin or hardener.

I have never had an old hardener fail to work, but I’m sure it’s possible.

Although cold temperatures will delay cure, they will not prevent cure. Raising temperature to normal range will bring about a cure.

Polyester and vinylester, on the other hand, are susceptible to cold temperature, and restoring normal range temperature may still leave one with a gummy mess.

Never mind Jack, if its already hot
then is should be going off …

Get out the utility razor and dig it out is what I meant. If it did not harden too much, and Acetone does not hurt surrounding finish, the acetone should clean out the little stuff you cannot. Wipe fresh, maybe sand once more for prep and start over.

Moisture in the air can slow cure down too, even in heat … If it was cooling down AND raining especially.

I messed up years ago building a catamaran and coated the entire inside of a hull that would not go off. West told me to keep heating it and if it does slow cure it would be very strong. It took about five days but was OK after that.

dig it out
Solvents for epoxy are acetone, lacquer thinner, alcohol and vinegar.

I would start with alcohol (bathroom) and use a tooth brush and see if that will dissolve it and get it clean. Acetone is strong and excellent except you have to be cautious that it won’t damage the other surrounding surface.

Yes, everyone has screwed up a ratio at some time and you never do it again. Also make sure you lightly sand and clean and areas that you are going to repair before using epoxy. Mold release will highly interfere with the hardening of epoxy.

Try Direct Sunlight
I’ve had good luck curing ‘stickys’ in direct hot sun - albeit slowly - the UV rays seem to help. If nothing else, you get a two or three day reprieve from the joy of removing the semi-cured stuff.

Had this happen once
I believe I may have inadvertantly mixed the proportions wrong and the hardener turned into a viscous goo that was almost impossible to get rid of. I tried several solvents, acetone, ethyl acetate. I think I ended up soaking the stuff in glacial acetic acid, which I don’t suggest unless you are a chemist. It took me a very long time to clean up the mess.

I lucked out !
This morning the tackiness is gone and it has hardened.

I guess yesterdays heat and low humidity did the trick.

In the future, I’ll pay closer attention to my mixture.

Thanks all for the various suggestions

Jack L

a lousy non structural mix.

You evidently read like you write ?
the OP said he was touching up scratches, not doing structural work


a bad mix is what ?

ignorance with know it all-ism.
We all have our strong opinions on here. But there’s no point in making them so strong that they decay.

Mixing booboos
Pumps can have bubbles, using food containers with dimple bottom can hide unmixed portions, laziness in mixing, etc.

My BooBoo came when West changed their pump volumes and I didn’t realize it. I bought a new epoxy pump with more volume and it didn’t match the old ratio of my hardener pump.

I found it much easier and more room for error using 2 to 1 ratio opposed to 5 to 1.