DickieB

I mixed that resin up just like the instructions said, "4 oz resin to 3 drops of hardner". This morning, it's still sticky wet. so was the resin in my cup/brush. I added a few more drops and in 15 minutes, the cup was hard as a brick!
Now, I get to scrape all that work off my big fender hole, and it was laid up so well!!!
How in the world do you know, by looking or heat, or whatever, that the resin has been mixed right?

Easy Mike

Put a heat lamp on your patch or get the car out in the sun light.

7T1vette

Just give it a little more time and some mild heat before you give up on it.

DickieB

Thanks guys! I was sooo disheartened. Though I'd have to scrape it all back off.
I tried a blow dryer last nite, but maybe that just wasn't enough. If I can't get it heated up, do you think it will still harden up? If so, will it be strong, or would the apparent "incorrect mixing" cause it to be brittle or overly flexible.

dochorsepower

Most two part resin systems are temperature sensitive. They even say do not mix or apply below a certain temperature, usually 65-70 degrees F. The cure curve has a "knee" about 65 degrees and lower than that the cure time increases exponentially. Heat works.

DickieB

Thanks. It was around 68 last nite, so you are probably right. I'll check when i get home tonight. Hope its cured up.

Easy Mike

68 is a little cool. Heat helps the resin set up. Heat lamp; sun light, etc. Over kill is not required.

DickieB

Well, when I got home last nite, it was still sticky. I tried heating it up with a heat lamp, but that didn't do anything appreciable.
So, I put on my gloves, and basically just wiped it all off. I cleaned it all up with acetone.
I made a new batch of resin, this time doubling the amount of hardener. Voila! Within 15 minutes, it was setting up, and after an hour, I was sanding it. Whew! what a learning curve!
Anyway, I peeled the plastic backing from under the hole after the resin had set up and it peeled right off. Amazing how hot it got all on its own! Exothermic, if I remember from chemistry ! Tonight i will lay up a few layers on the underside feathering each layer larger.
Does this sound like the right way to go, or am I going to regret this step too?

Priya

I had the same problem with some fiberglass I put in a wheel well. After 1/2 hour, 2 hours, 1 day it was still soft. Tried using a heat gun on it for quite a while and it was still soft. A day after that I finally pulled it off and threw it beside the garage and the damn thing was hard a couple of hours later. Something about a garage just prevents fiberglass from hardening as quick as it will outdoors. Now I use quite a bit more hardener than is recommended and it comes out okay.

doorgunner

I know what you're talking about---scarey/sticky/patch:

Loo-z-anna 80*F.......but 99% humidity....

The 2" square patch on the heater box is 3 days old & still tacky but firm...

I should have misted a few drops of hardener over the patch on day #2 with a sinus-spray bottle to finish hardening the repair--LOL

Next time I'll adjust the hardener by increasing the number of drops by 20% on humid days in the garage.