Epoxy still sticky, has not set, what to do?

[driftwood]

Have a few small areas that needed sealing for water protection around wooden doors, so I bought a RAKA test kit with both Fast and Slow hardeners. First time using expoxy. Experiemented on a wood scrap. Fast heated up fast, and worked fine. Slow took overnight to cure, and worked fine.

Was comfortable with using it, so applied Slow to tear. First two coats worked fine. Had few small areas that needed one more coat, so made one more 1 oz batch and used the Fast. Used graduated pot that came with kit and believe I measured precisely. Stirred 2 minutes as instructed. Applied to tear 20 hrs ago, and it is still sticky.

What do I do? Will it harden with time? Do I need to take corrective action now before it hardens? And why would it not have worked when the test area worked fine with the Fast (seems obvious answer is ratio or mix problem, but don't believe I erred there- did one oz. resin and half an oz. hardener in a tiny batch, and temp conditions the same as other applications).

Any advice much appreciated....

[eamarquardt]

If you can put it out in the sun as much as possible. That always seems to work for me. If that doesn't work take some acetone and get as much off as possible and apply another coat on the tacky areas mixing the batch a bit "hotter".

Hope this helps.

Cheers,

Gus

[pohukai]

You say you measured it precisely and with my experience with my teardrop and kayak building; just getting close should be fine. However, the cure time will vary. I have read that even with a only a little bit of hardener, the epoxy will eventually harden but it isn't worth proving/disproving the hypothesis on your teardrop.

[angib]

The first thing to try is to heat up the job. Do this by 'tenting' it (building a quick 'n' dirty plastic sheet tent all around it) and sticking a fan heater inside the tent with its thermostat turned up high. You probably won't get the job too hot but keep an eye on things like melting the plastic sheet! Leave like that for up to 12 hours and it should start the epoxy curing, if it was mixed nearly right. Don't be afraid to leave it for 24 hours if 12 hours doesn't do it.

If the epoxy mix was really wrong then you may have to try to remove it, but try the heating technique first.

Gus, the suggestion to put a 'hot mix' over it only works with polyester resin and not with epoxy resin. Never, ever intentionally change the resin/hardener mix ratio on epoxy - it can only end in tears.

[driftwood]

Thanks guys. It is slowly beginning to harden...so may be ok eventually, think I will give it a few more days.

Angib, I assume the purpose of the tent is to retain the heat, correct?

[kirkman]

When we build glass kayaks the thing we find helps speed the curing time is putting the part you want to cure faster out in the sun.

[H.A.]

Sometimes with my epoxy jobs the stuff cures fine but for whatever reason its surface just remains sticky.
I clean off the surface and all is well.
But, Seems like its working out for you.
Good luck with it.

[angib]

Angib, I assume the purpose of the tent is to retain the heat, correct?

That's right - it was usually in a factory so trying to heat the whole factory up hot wasn't going to work. If it's just a garage, then you don't need the tent, just the heaters. You're just trying to get the workpiece up to a temperature where the epoxy can go off on its own.

[doug hodder]

While I'm no expert on it, it may be the humidity that has caused an issue. I see that you are in Alabama, so you have much higher humidity than many of us. From what I've read, they say not to use the slow hardener in a high humidity environment. Is is curing clear or cloudy? If it's cloudy, that's a moisture issue. I can only speculate on it as I have a shop heated with a wood stove so it's a very dry area and I run it up to about 80 when I do large areas of epoxy coating. It may be that certain epoxies are more sensitive to humidity than others. I always mix per the instructions and work within the recommended temp ranges and have had no issues with curing or blush on it. Other opinions may vary. Give it some time...It'll go. Don't sand till it's fully cured however, you'll just waste sand paper on it. Doug