The Resin Didn't Kick !

[SurferShane]

Originally Posted by delmarrey

I once laid up 30' x 2' - 6 oz glass with epoxy that had the wrong mix (got the wrong pump) and it was a real job trying to get it all off. It sat for a week and just became gummy.

At least polyester seems to eventually want to set? Get any moisture etc in epoxy and instead of a rock hard crisp finish it permanently turns into opaque soft plastic.

[Waterborn]

Be aware that epoxies like West System are chemically engineered to have a certain amount of hardener mixed to the resin. I beleive within 5% of the specified ratio is safe, but more or less than that and you have non-cured gum on your hands. That is why they make a range of hardeners for varied "kick" times. Mixing well (scraping off the sides of the container and rolling into the mixture) for several minutes is the key. I have used older hardeners with no problems. It turns a redish colour over time, but I contacted the Geugeon Brothers (West System) about this ten or twelve years ago, and was told that it will still work just fine.

Polyester, on the other hand, -The more hardener you add, the faster it kicks- and yes, you can make it kick so fast you can't hold the container in your hands and can run risk of fire.

[delmarrey]

Originally Posted by SurferShane

At least polyester seems to eventually want to set? Get any moisture etc in epoxy and instead of a rock hard crisp finish it permanently turns into opaque soft plastic.

There are different grades of epoxy. Some of the stuff I use is a 4:1 mix and a 2:1 mix, which also have a slow, medium and fast set for each.

The 2:1 mix is more flexible, which I use for areas of high flex but the 4:1 for hard surfaces or bonding like a deck or bulkhead.

If epoxy gets wet before it cures it has a gummy finish but will cure up if another coat is applied.

Fiberlay: Characteristics of Pro Glas Epoxy System

[gpshephe]

I had the same problem. sticky for longer than a couple days. It ended up with not being mixed well enough. make sure you stir and stir and stir. not until you like the color, but make sure they get kneaded together well. Just my experience.