Epoxy won't harden

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Epoxy won't harden

Post by anonymous » Sun Nov 27, 2005 8:49 am


To all experienced or experts on epoxy and fiberglass out there. This is shameful but I really need your advise coz this is my first project yet. How would you recommend to repair a portion of fiberglass lay that won't harden. All the other parts have already hardened except that portion. I don't know which procedure or preparation was wrong. Can't proceed fairing coz of this.

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Post by hank » Sun Nov 27, 2005 9:18 am

Dear Guest

In my opinion there's only one thing for it. Just scrape off all the sticky stuff and sand until the surface is 'dry'. Then apply new epoxy and wait for it to harden.

I had to do all of the above after I messed up and added more resin where I should have used hardener. You can't add hardener to already applied epoxy so there I was... Mechanical removal (the scraping and sanding) was the only way out.

Again, this is my opinion. I hope someone comes up with a better plan.

Good Luck

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Post by roob76 » Sun Nov 27, 2005 9:34 am

i have actually mixed a wrong batch before but caught it before i applied it to the boat. i reversed the mixture on accident.

if it's been over a week at room temp or above and has not cured it most likely won't.

good thing is if the mixture was really off you may be able to just peel up the fiberglass and just scrape away the rest of the uncured resin. clean it with acetone really good to make sure there s no left over uncured resin and start over!

make sure you get the right mixture. if using pumps to mix your resin make sure they are pumping out the right amount. i stopped using the pumps because of this. sometimes they loose their prime and you get a good size air pocket spitting into your mixing cup and if mixing small amounts this is not good. also make sure you are stiring it good. i usually stir until i see all the swirls in the resin gone and then stir some more constantly scraping the sdes and the bottom of the cup with the mixing stick. use smaller amounts so you can stir a bit longer without fear of it starting to gell in the cup.

i am by no means an expert. this is just the method i use and it works for me!

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Post by Old E. » Sun Nov 27, 2005 10:13 am

What Roob said. You should be able to scape it off and wipe with acetone etc...

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Post by tech_support » Mon Nov 28, 2005 10:26 am

The mix ratio must not have been right. If the temp. is over 50 degrees, it should get hard within a day (no matter the brand)

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