Problem with flowcoat not drying

[amoret]

Hi, I applied flowcoat over 2 areas inside my trailer sailer. One area = no problem, the other = big problem. Problem area has stayed tacky and smelly for 5 days now. This is probably because the day before I had laid wests epoxy resin over the rough fiberglass surface to tidy it up. The epoxy was dry and hard before I applied the flowcoat and I had sanded with 100grit.

The temp gets down to 1-2 deg Celsius at night, but 15 - 16 C during the day, have had fan dryer on over night. So my question is: will the flowcoat ever dry/harden and stop smelling? And what is the best remedy if it never dries? Looks like a hell of a mission to wipe off. Acetone?? It's a confined space, i.e. storage area under quarter berths towards the back. So not looking forward to sticking my head down there for long periods. So any help or suggestions will be very much appreciated!!

Thanks in advance
Bruce G

[valhalla360]

Epoxy doesn't cure by drying out, so not sure what the fan is for (getting warmer outside air into the enclosed space?).

If it's been 5 days and gets up to 15C for a significant part of the day and the other pour did cure, sounds like you got your mix ratio off.

Clean up is likely to be a problem depending on how much it cured. If it's solid but tacky, you can give it another week or two and hope. I'm assuming by "flowcoat" it is non-structural. You could try another coat over the top to seal it in. Otherwise, scraper, sandpaper and a lot of cussing.

If it's still liquid/semi-liquid, acetone, lots of disposable rags and a lot of cussing.

[amoret]

Thanks for reply. it was the same mix ratio for both jobs. Difference being the successful job was over a painted surface, the unsuccessful job was over epoxy. I'm thinking maybe the epoxy wasn't fully cured, even though it was hard.
It's not structural, just cosmetic, and mmm yes still a bit runny, sticks to finger tips if I touch the surface.
Maybe lots of paper, acetone, cussing etc

[UNCIVILIZED]

Adding another layer of epoxy overtop of one which is partially cured not only shouldn't cause any problems, it's the preferred way to build things. As when done this way, both layers chemically bond together, as well as having some mechanical bond strength between them. Which is what you want. Assuming that is, that all of the layers are mixed in the correct ratios, so that there aren't any cure issues.
Which, if your flow coat hasn't cured by now, it's not going to, sadly. And it'll likely be a beast to remove it. Not to mention an expensive mistake.

[valhalla360]

Originally Posted by amoret

Thanks for reply. it was the same mix ratio for both jobs. Difference being the successful job was over a painted surface, the unsuccessful job was over epoxy. I'm thinking maybe the epoxy wasn't fully cured, even though it was hard.
It's not structural, just cosmetic, and mmm yes still a bit runny, sticks to finger tips if I touch the surface.
Maybe lots of paper, acetone, cussing etc

I still suspect the mix ratio is off. Even using the west epoxy pumps, you will occasionally get a pump that has some air mixed in. The other possibility is did you do a good job mixing. If not, the ratio will be different throughout the mixture with some portions having too much hardener and others not having enough.

Over painted surface or partially cured epoxy should have no effect on cure of the new batch.

Might try going to the west epoxy website. They have lots of how-to's and might have ideas for cleaning up a poor mix.

[Terra Nova]

Wipe it all off. Clean with solvent. Pay attention to catalyze the resin next time.

[JOHNMARDALL]

Before you do anything, talk to the people at West System- they are very helpful. Did you thoroughly wash the cured epoxy with water before applying the flowcoat material? Amine blush may have contributed to your problem.

Good luck
John Mardall
Vetus Maxwell Group

[Rapanui]

If the flowcoat is not epoxy ie polyester, it will not cure over epoxy. You can epixy over polyester but not the reverse. Don't ask how I found out.

[Cheechako]

I have had problems with paint curing over epoxy before also. Not sure why. In some cases "epoxy paint "with "epoxy paint" overcoat over it. I don't think those paints are actual epoxy but not sure though.
I wonder if you wiped the surface with vinegar if the tacky would go away? Vinegar is used for clean up of epoxy right?

[valhalla360]

Originally Posted by Terra Nova

Wipe it all off. Clean with solvent. Pay attention to catalyze the resin next time.

Epoxy doesn't catalyze. The two parts are mixed in specific ratios and chemically combine into a new material. To much or too little hardener and there will either be left over hardener or left over resin which will never cure and there is no good way to introduce more hardener or resin after the fact.

This is different from polyester resin where a catalyst causes a chemical reaction but makes up a negligible part of the final mixture. The amount of catalyst controls the speed at which it reacts. In practice a few drops can turn a gallon into a solid mass if allowed a few weeks to catalyze

Even if the old coat of epoxy wasn't fully cured or cleaned, the new batch should still cure. Worst case if you have bad case of amine blush, it may cause the new layer to delaminate but it will still cure just fine (amine blush is a waxy byproduct that forms on the surface of epoxy).

[Terra Nova]

Originally Posted by valhalla360

...Even if the old coat of epoxy wasn't fully cured or cleaned, the new batch should still cure...

Not without hardener.

[valhalla360]

Originally Posted by Terra Nova

Not without hardener.

Obviously, re-read my comment. It was in regards to old partially cured materials underneath or if the OP didn't clean the amine blush.

To make it clear for you, thoughly mixed in the recommended ratios, partially cured epoxy underneath won't stop a new batch from curing just fine. That new batch may or may not adhere to the old batch depending on what is wrong with the old batch.

[Terra Nova]

This has nothing to do with adhesion. OP failed to add hardener to last coat.

[amoret]

I should clarify...It's the flow coat laid over the epoxy that won't dry. From comments above I suspect the problem is that amine blush wasn't properly removed from the epoxy. The amine blush has contaminated the flow coat preventing it drying/hardening.
The other area that was flowcoated has worked very well because it was not laid over fresh epoxy. The same mix ratios and procedures were used for both jobs. The catalyst used with flow coat is called MEKP and 1-2 % is recommended. I thoroughly 10 ml into 500ml of Flow coat (2 %).
It's interesting that the Flow coat won't dry due to Amine blush as Flowcoat is just Gelcoat with a wax added to it.
Thanks for all the input, sounds like it aint gonna dry. Looking like a messy clean up ahead.

[barnakiel]

Amines problem likely.

Some epoxies require weeks before coating over. But once dry and hard you can wash the job VERY VERY well and apply the paint. It will dry just you have to repaint sooner as it will not stick to the epoxy as well as it could if you cured the epoxy job very well.

b.