"tacky" epoxy
 

Hi,

I have recently done a repair to my firewall using fiberglass and epoxy. I used 2 hour epoxy I got from the LHS, (can't remember the brand off hand). I used a "little" extra hardening liquid in relation to epoxy (this may have caused my problems, though I am not sure).

24 hours after I did the repair, the epoxy is still "tacky" to the touch and hasn't set completely. 36 hours later it is a little better, but still somewhat sticky.

Since this is a repair at a critical point, will I be ok? Will this ever set? Can I do anything now to help it better set? How can I prevent this from happening in the future?

Thanks for any info here...

"tacky" epoxy
 

Bret:

Use your heat gun and heat epoxy till it starts to flow then let cool. This will set off the curing at a faster pace. Should be rock
hard in about 10/12 hrs.

"tacky" epoxy
 

Epoxy is very sensitive to the correct ratio of hardener to resin. Be it epoxy resin or glue. Extra hardener will not help the cure process, as you have just found out. It will cure in time, try and find a continuously warm spot for it.

Polyester resin on the other hand can have it's cure rate modified by varying the amount of hardener. However polyester resin should not be allowed for domestic use.

Ed S

"tacky" epoxy
 

Another snag I have run into on occasion is incompletely mixed epoxy. If resin & hardener are not thoroughly mixed, the unmixed resin will stay tacky more or less forever. Be sure you mix thoroughly. I use a popsicle stick with the end squared off on my little table saw, so I have a flat foot to scrape everything off my mixing surface and get it up into the mix. I scrape and swirl for a full minute to be sure of getting a complete mix. I use plastic container lids for mixing. When the mix is cured, just bend the plastic surface and you can pick off the epoxy and have a clean suface to go again. Easier to get a good mix working on a flat surface as compared to the little plastic cups, where resin can hide in the corner.

"tacky" epoxy
 

Did the heat gun suggestion last night. This morning it appears to be well set.

In the future I will make sure that I mix in the proper ratios and mix very thoroughly.

Thank you everyone for your suggestions/help.