Epoxy sticky after four days

my advice is to throw that ocean cleaning ship away and go become a janitor in a school so your in less peoples way. oh any buy a south board kook?? dont you know what to make a hello threade, people are so rude these days.

 

epoxy takes a while to fully cure. What are the temperatures you are glassing at and is there any uv light anywhere?

 

It's probably due to adjusting the mixture and might not ever cure. Or you could have had contamination in what ever you mixed it in. Or even dampness or water could mess it up.

Regardless of how it happened- I would advise to sand as much out as you can- and put another coat on top. Mask out the area with tape and make a regular mixture and use a cheap paint brush to apply it. It's a pain- but it has happen to me before and is usually due to what I stated above.

 

Dude, the thing about epoxy resin is that it absolutely will not harden if you get the ratios wrong. That last batch you mixed that was not exactly 2 parts resin to one part hardener will never cure. Scrape it off completely and start again but make sure you get all of the bad batch off. Acetone will help and sand it also if possible. Do not get acetone on the bare foam or it will melt it and you don't want that.

 

direct sunlight is never a good idea for fiberglass. sunlight will not help it cure, the uv will only cause weakening, yellowing. Fiberglassing is a chemical reaction, resign and hardener need the right ratio and mixed properly

 

Please follow instructions carefully!
Exactly!

 

Well, I mix my epoxy resin hot every time. I prefer it that way. When I say hot I mean the right ratio--with an extra splash. I have never had any issues with a hot mixed epoxy. However, that is just me. I don't know what type of epoxy you are using.

Also, humidity and temperature are a big deal. You said you did some other patches underneath--I know they were hard but were they fully cured and no longer gassing? Did you sand them prior to putting on the hot-coat?

One last thing I do is let the mix "set". I shaped a board a long time ago with a shaper in Florida who told me it was important to always let your mixture set for 15 minutes prior to application. I have always done this but when I use epoxy the set is 10 minutes. I mix the A & B for at least 5 minutes. This might be overkill but I have never had a reason to change it.

Sun exposure will not change anything unless it is a sun activated. It actually might make things worse.

If it is still not curing, scrape and clean off with acetone and try again.

Good Luck

 

Also, Did you completely remove the old patch that shop put on and dry the board out?

If you repaired with a couple patches and they cured and it was cool it may appear fine. however, if the board is exposed to the sun and the foam heats up and the air pressure rises, it will cause any water to find an exit. If saltwater mixed with your resin, even a minute amount -- you'd be out of luck. This might be an issue of timing

 

Polyester resin hardens via catalytic reaction, and you can adjust the amount of catalyst (to a point) without changing the physical properties of the hardened resin, and only affecting cure time. But even with poly you can run into problems if you try to kick it too hot.

Epoxy is not a catalytic reaction... it's a cross linking reaction, where the molecules of the resin and the molecules of the hardener have to be physically mixed together so they can sort of "hold hands" to form a complete chain that cures over time. If each molecule of resin doesn't have a molecule of hardener at each end, the chain is broken and the resin will never set properly. Same thing the other way around... too much hardener means there's hardener molecules that are free floating, so the epoxy never gets to fully cure.

Most epoxies have a "margin of error" that you can still work within, and still get a decent cured product at the end. You've exceeded that margin of error for the epoxy you're using.

 

Maybe you should try balloon knotting your mixture. Depending on the ratio, this can get messy and the smell can be pretty strong, but once you get it right, you'll feel better

 

So horrible Z. So Horrible...

 

True story here.....About 10 years ago I shaped and glassed a board for a friend using RR epoxy...calls for 2:1 ratio. I mixed 24 total ounces for the deck lamination, glassed it and hours later when it was still slightly gooey I knew something was horribly wrong and realized I had used 18 oz. resin/6 oz. hardener. So 3:1 OOPS!

Turned up the heat in my shed and let the board sit for a couple days, went ahead and hot coated it knowing it still felt soft to me but whatever, told my friend to let me know if there were any issues but left it at that not wanting to bum him out.

10 years later, he still tells me its fine...it was a fish, so the 6/4 deck lam probably helps.

 

Yes- only poly (as stated above) can be mixed hot. It will actually get hot. Keep in mind that a hot mix vs regular will not be as strong in the long run. You gotta mix epoxy as per spec.

Also you mentioned about doing a repair right before dark. I have noticed that the issue you had can also result from doing a repair OUTSIDE right before dark and letting it set outside for an hour or two info dusk/dark. The dew or something can get everything wet and moist- thus the bad cure. Always being the board in before that time.

 

I mis-measured an epoxy hotcoat once and it never cured. Ended up scraping off what I could, used distilled vinegar to remove even more, then re-hotcoated over top of that. The surface hotcoat cured, but there were a few pinholes in the top hotcoat (likely from bubbles) that would ooze out uncured goo when the board got hot.

Epoxy is weird stuff. So many variables that can make things go wrong.

 

Joshua, you are a very kind man for coming to this forum for advice on your jellyfish resin thingy. The kind we don't like! Prease paddle out in giant nuclear waste filled slop with a go pro and send us video and then die. Bonzai mofo!