Marinepoxy curing oddly

See our FAQ and tutorials before posting.
rezab
New Poster
New Poster
Posts: 7
Joined: Wed Jun 17, 2020 3:14 pm
Location: Connecticut

Marinepoxy curing oddly

Post by rezab » Sat Jun 27, 2020 4:33 pm

I've noticed something odd going on with the cure of the slow marinepoxy that I've been using. After mixing a 2:1 ratio and waiting 2+ days, it seems to have cured totally hard, but if it's left in the sun, and heats up, it gets soft and flexible. I've mixed up two batches and the same thing has happened with both, so it's not that I messed up the mixing ratio without noticing.

Any ideas as to what could be causing this? I've worked with west systems and other epoxies, and have never noticed anything like this happen.



User avatar
OrangeQuest
Very Active Poster
Very Active Poster
Posts: 3067
Joined: Tue Aug 28, 2018 1:14 pm
Location: Houston, Texas

Re: Marinepoxy curing oddly

Post by OrangeQuest » Sat Jun 27, 2020 7:33 pm

How is the epoxy getting and why you leaving it out in the sun. Epoxy does soften in the heat but afterwards it gets harder then, but I think the heat needs to be about 130° or more.
"that it isn't just an ordinary sort of boat. Sometimes it's a Boat, and sometimes it's more of an Accident. It all depends." "Depends on what?" "On whether I'm on the top of it or underneath it."
A. A. Milne

rezab
New Poster
New Poster
Posts: 7
Joined: Wed Jun 17, 2020 3:14 pm
Location: Connecticut

Re: Marinepoxy curing oddly

Post by rezab » Sat Jun 27, 2020 8:33 pm

I certainly don't think it is getting to 130°. The outside temperature is mid 80s and I don't think the epoxy more than 20, maybe 30 degrees hotter than that.

It was in the sun just while I was working outside on the piece, not more than an hour.

fallguy1000
Very Active Poster
Very Active Poster
Posts: 5472
Joined: Tue Jan 12, 2010 12:25 am

Re: Marinepoxy curing oddly

Post by fallguy1000 » Sat Jun 27, 2020 11:57 pm

rezab wrote:
Sat Jun 27, 2020 4:33 pm
I've noticed something odd going on with the cure of the slow marinepoxy that I've been using. After mixing a 2:1 ratio and waiting 2+ days, it seems to have cured totally hard, but if it's left in the sun, and heats up, it gets soft and flexible. I've mixed up two batches and the same thing has happened with both, so it's not that I messed up the mixing ratio without noticing.

Any ideas as to what could be causing this? I've worked with west systems and other epoxies, and have never noticed anything like this happen.
7 days is typical full cure
Epoxy needs time
My boat build is here -------->

viewtopic.php?f=12&t=62495

rezab
New Poster
New Poster
Posts: 7
Joined: Wed Jun 17, 2020 3:14 pm
Location: Connecticut

Re: Marinepoxy curing oddly

Post by rezab » Thu Jul 02, 2020 7:22 pm

Its been more than 7 days now, probably closer to two weeks, and it seems to have totally cured hard, but I was sanding some of the epoxy, and just the heat from the friction made the epoxy gummy. Either marinepoxy has an absurdly long cure time, or I'm starting to think I've got bad epoxy.

fallguy1000
Very Active Poster
Very Active Poster
Posts: 5472
Joined: Tue Jan 12, 2010 12:25 am

Re: Marinepoxy curing oddly

Post by fallguy1000 » Thu Jul 02, 2020 11:18 pm

rezab wrote:
Thu Jul 02, 2020 7:22 pm
Its been more than 7 days now, probably closer to two weeks, and it seems to have totally cured hard, but I was sanding some of the epoxy, and just the heat from the friction made the epoxy gummy. Either marinepoxy has an absurdly long cure time, or I'm starting to think I've got bad epoxy.
No. Run a test batch.

Real easy to mix hardener heavy or hardner for resin in small batches, or fail to stir.
My boat build is here -------->

viewtopic.php?f=12&t=62495

User avatar
OrangeQuest
Very Active Poster
Very Active Poster
Posts: 3067
Joined: Tue Aug 28, 2018 1:14 pm
Location: Houston, Texas

Re: Marinepoxy curing oddly

Post by OrangeQuest » Fri Jul 03, 2020 5:08 am

Could be you are sanding blush. The waxy buildup will gum up a sanding disk.
"that it isn't just an ordinary sort of boat. Sometimes it's a Boat, and sometimes it's more of an Accident. It all depends." "Depends on what?" "On whether I'm on the top of it or underneath it."
A. A. Milne

Jeff
Site Admin
Site Admin
Posts: 6471
Joined: Fri Apr 29, 2016 12:17 pm
Location: Vero Beach

Re: Marinepoxy curing oddly

Post by Jeff » Fri Jul 03, 2020 7:56 am

Reza, give Reid a call next Tuesday as he is away for the holiday weekend (772.742.8535). We have had no issues related to our MarinEpoxy and something is just too odd here. I agree that you should test but I would prefer you talk with Reid before your next steps. Again, we have had no issues with any of the speeds of the hardener in the recent heat wave that many of our builders have suffered. Jeff

rezab
New Poster
New Poster
Posts: 7
Joined: Wed Jun 17, 2020 3:14 pm
Location: Connecticut

Re: Marinepoxy curing oddly

Post by rezab » Fri Jul 03, 2020 8:42 am

fallguy1000 wrote:
Thu Jul 02, 2020 11:18 pm
rezab wrote:
Thu Jul 02, 2020 7:22 pm
Its been more than 7 days now, probably closer to two weeks, and it seems to have totally cured hard, but I was sanding some of the epoxy, and just the heat from the friction made the epoxy gummy. Either marinepoxy has an absurdly long cure time, or I'm starting to think I've got bad epoxy.
No. Run a test batch.

Real easy to mix hardener heavy or hardner for resin in small batches, or fail to stir.
I've run a few test batches and have had the same results.
Jeff wrote:
Fri Jul 03, 2020 7:56 am
Reza, give Reid a call next Tuesday as he is away for the holiday weekend (772.742.8535). We have had no issues related to our MarinEpoxy and something is just too odd here. I agree that you should test but I would prefer you talk with Reid before your next steps. Again, we have had no issues with any of the speeds of the hardener in the recent heat wave that many of our builders have suffered. Jeff
Thanks, I will.

fallguy1000
Very Active Poster
Very Active Poster
Posts: 5472
Joined: Tue Jan 12, 2010 12:25 am

Re: Marinepoxy curing oddly

Post by fallguy1000 » Fri Jul 03, 2020 8:59 am

Jeff wrote:
Fri Jul 03, 2020 7:56 am
Reza, give Reid a call next Tuesday as he is away for the holiday weekend (772.742.8535). We have had no issues related to our MarinEpoxy and something is just too odd here. I agree that you should test but I would prefer you talk with Reid before your next steps. Again, we have had no issues with any of the speeds of the hardener in the recent heat wave that many of our builders have suffered. Jeff
The only times I have experienced heat gumming is on cold cured epoxy that has not kicked or I have experienced gumming on understirred epoxy or also if I have botched the ratio and gone 1 resin and two hardener, or if I use a small batch and too much hardener.

Epoxy will soften under a heat gun. This is to be expected and no different epoxy will behave differently.

If you test the product; the tests should be done using a gram scale and using the weight ratios. The weight ratios are different and more accurate.
My boat build is here -------->

viewtopic.php?f=12&t=62495

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest