Two-Part Epoxy Problem

I’ve got two part epoxy. It’s Resin and Hardener. Normally, it goes in a 3:1 ratio and life is good. I’m out of Hardener. I bought some made for fiberglas epoxy, instead of made for carbon fiber epoxy.

Dribbled in a bunch of drops, as though I was adding to the fiberglas epoxy resin. Mixed it, applied it. That was 4 hours ago on a hot breezy pretty dry day. It’s as though I just applied it to the cloth. Feels 90% as oogey and wet as it did.

Here’s the question: Assuming I have limitless patience, will this stuff set up properly in a few days, or lacking hardener will it remain oogey forever?

Can I GET more hardener and brush it onto the resin and hope it will “set up” that way, or is that a really bad idea?

Should I slough off the carbon fiber cloth and just call it a minor loss, order more hardener and wait till I can mix properly?

Bottom line issue: Does Epoxy Resin dry and harden eventually without Hardener?


Well, someone cleverly spilled a gallon of resin in a cupboard at work and it was still on the floor, an inch and a half deep, four years later and as treacly as ever. Awfull job to get rid of it.

There are different resin formulations for what is generically called “epoxy” and the type of fiber used with it is really irrelevant; it is resin itself that matters. So it seems pretty obvious that the hardener you have is not the right one for the resin that you have. I suspect it will never harden. Brushing on the appropriate hardener will harden the surface but it won’t penetrate down and harden it all so I think your best bet is to call it a total loss and start over.

If you’re referring to the hardener for automotive and marine fiberglass repair kits, that product is methyl ethyl ketone peroxide, and I wouldn’t mix it with something like Abatron or JBWeld. Each mix is somewhat proprietary, and if you intermingle, you get some kind of questionable goo.

**Questionable Goo[/]. Hmmm. Not only an excellent band name, but an accurate description of what I left outside tonight.

Luckily, it’s the overcoating placed onto a very well made and rigid device. I can slough off the resin and carbon fiber sheet ( hate to waste the c.f. sheet… ) and wipe it down, buy more hardener for the resin and in a few days, do it right.

Dang. :slight_smile:

there are two main types of fibre(glass) resins

  • epoxies which are normally mixed 1:3 or 1;1 with a hardener (usually an amine (fishy smell) or sulfide (can smell sulfourous)). The epoxy itself usually doesn’t have a strong smell
    styrene based - the harder is a peroxide which is added in small quantities, typically 1%. The styrene is quite volatile and smells quite “chemically”,

Neither will set by themselves. If you want to add more hardener to the epoxy (apart from mixing problems that have been mentioned above) it could work, but I would be worried about what the previous hardener had done, and almost certainly the material will be alot weaker than normal. Any styrene based material will be useless by now as the styrene would have evaporated.

-grin- that might explain one thing. I did try mixing the resin made for fiberglas with the hardener that came with it. I guess it was styrene based- it reeked something awful.

I mixed it in a styrofoam bowl. The hardener hardened in about 4 minutes instead of 30, and the bowl dissolved. It was rather interesting…

I just went out to take a look. Indeed, it is as though I just applied the liquid 5 minutes ago. So I pulled it off and cleaned off the piece as best as I could with paper towels. Dang.