What's wrong with my epoxy resin?

[i386]

I mixed some filler (resin, Glass Bubbles, Cabosil). After about 14 hours it still hasn't fully cured. It also has a slight light orange tint to it.

The first time this happened I figured I didn't measure properly or mix well enough. This time I'm sure I did.

I scraped/sanded it all off the first time. Looks like I'll have to do it again. Meanwhile this is holding up my priming/painting that I'm trying to get done before it's too cold.

Could it have all of a sudden gone bad? Maybe I just need to mix up the hardener really well since i'm near the bottom of the jug?

 

[jonesg]

Re: What's wrong with my epoxy resin?

I'd try applying some heat, see if that trips it off.

 

[WizeOne]

Re: What's wrong with my epoxy resin?

It does seem unusual. With epoxy it is pretty hard to measure wrong. It's either 1:1, 2:1 or 3:1 and a few percent off should make no difference.

Did you mix the catalyst before you put the fillers in? What is the temperature out? Can you shroud the work and put a heater under it?

I've heard said that epoxy can get old, but I have several year old stuff that still works fine.

 

[reelfishin]

Re: What's wrong with my epoxy resin?

Temperature and humidity can cause what you are seeing. Try ventilating the area and raising the temperature a bit.
If that don't help, try washing the surface and letting it dry.

 

[i386]

Re: What's wrong with my epoxy resin?

It's a lot harder than it was this morning. I can still dent it with my fingernail but it no longer feels rubbery. I will leave it be for a while and see if it hardens.

 

[jonesg]

Re: What's wrong with my epoxy resin?

Its too cold, apply heat to cure it.
It might set but won't be fully cured til the temp is raised...one way or nuther.

 

[oops!]

Re: What's wrong with my epoxy resin?

as you guys know....im not an epoxy guy, but there is a theme with all resins, and that is mix mix mix.....before you add any ingrediants....mis well....check out the egg beater on the drill....i mix resin (in the pail) before i pour and add cat.....

for gellcoat....it is suggested by the manufacturers...that you mix it for 15 mins before you add the cat

 

[Mark42]

Re: What's wrong with my epoxy resin?

The epoxy I used says to mix for 3 minutes before use. I noticed that in the bright sunlight, you could see the resin and hardner swirls if not mixed well enough, but in room light, it all looked clear and mixed. So I started checking it close in the sunlight before applying to the cloth.

I mixed a batch not exactly to the spec, and it took a while to harden, but it did harden. I agree with adding heat. If you have one of those aluminum reflector light housings, put a heat lamp in it and point it to the epoxy. Keep it a few feet away, don't want to start a fire.

 

[BillP]

Re: What's wrong with my epoxy resin?

I've heard rumor that epoxy has a shelf life but testing different brands 15-20 yrs old don't prove that to be exactly true. Whatever though, epoxy can take days to get hard in cool climes. Unlike poly resins that never dry if not hard within xx hrs, epoxy can take days to finally get hard in cool temps. Epoxy relys on chemical reaction to cure...temperature just speeds or delays the process but doesn't stop it. Don't dispair. Let it sit alone for a few more days. Based on my experience with epoxy I'm betting it eventually get hard as a rock and you will be a happy camper.

bp

 

[i386]

Re: What's wrong with my epoxy resin?

Thanks for the replies guys. I think it's the temperature. I've had this 1.5 gallon kit for a few months and have had no problems. I expected to have curing problems early on in the project since I was new to using the material but it never happened until now. It cured fine last week. I know exactly what Mark means about the swirling. I noticed it too. In fact, I always mix mine under light until I see the swirl disappear. This is probably my 5th 1.5 gallon kit and I've never had a problem before. I've never used it at this temperature before though. I've also noticed as the day wears on, the orange tint I mentioned is fading away.

 

[daviscfad]

Re: What's wrong with my epoxy resin?

I also believe it is the temp. When i worked at the boat yard in pompano beach fl. It didnt get cold much but when it did the resin didnt hardly want to come out of the barrel. And it took double the time it normaly did to kick off

 

[i386]

Re: What's wrong with my epoxy resin?

Good news. It finally cured. I sat an electric heater in front of the bow for a few hours and it's now hard as a rock. I had several places to sand and that went well. The filler I spread on the bow is pretty thick so I think I will save that job for tomorrow. I'm still working to get that area smooth before painting. There's a good chance I can get the 2nd primer coat on tomorrow.

 

[redeye1962]

Re: What's wrong with my epoxy resin?

that is weird. I notice when it gets around 110 my resin will get mushy, when cooled to 80s it will get hard. this concerns me if I was to put something over the resin it will not stick.

 

[jonesg]

Re: What's wrong with my epoxy resin?

that is weird. I notice when it gets around 110 my resin will get mushy, when cooled to 80s it will get hard. this concerns me if I was to put something over the resin it will not stick.

You mean in the can,virgin resin?,
or mixed resin/hardener?

 

[j_martin]

Re: What's wrong with my epoxy resin?

On Mixing epoxy, I mix thoroughly, scraping the sides of the container carefully, for several minutes.

Then I pour the whole works into a clean container, discard the original container and mixing tool, and do it all over again.

There are epoxy resins that will kick in two minutes, and some that will take 24 hours or more to kick, and weeks to cure. There's application for each of them.

Also, some get real hard, and some will stay quite flexible. Again, different applications call for different resins.

hope it helps
John

 

[redeye1962]

Re: What's wrong with my epoxy resin?

You mean in the can,virgin resin?,
or mixed resin/hardener?

I am not sure what you mean but I get a can of resin and then a tube of hardener and mix myself................not scientific but when cool the resin will be hard when hot it gets a bit mushy. I have noticed the longer it has a chance to sit on the wood it gets harder, of course we have not been above 100 in a while. I will find out next summer.