Boat Builder Central - Builder Forums

I mixed up 24 grams of MarinEpoxy yesterday afternoon (65-70 degrees and slow 350 hardener) and started laying up a part in a mold I built. Its curing nicely 16 hours later, but not sand-able yet and I want to continue laying more glass now.

How long of a time window at 70 degrees do I have for a chemical bond, or in other words not needing to sand or wash to continue laying on epoxy and glass? And how long at 80 degrees?

Thanks!

Should be sandable within 12 hours. If it is still in its green stage, you can safely apply "Wet on wet" without sanding, and still get a chemical bond.

Thanks Jamie..

After laying up a part with fiberglass cloth, Iv found that it takes at least 24 hours, or more to be sand able. It must be the lower temperature in the 70's and the slow 350 harder. But I still washed the part before more layers..

I'm guessing at those temps, a chemical bond would still occur 24 hours later. No washing..

But from what Iv read, there's not much amine blush to worry about with the slow 350 hardener anyway.

Dittos. Say u r okay, sans amine blush at overnite. I never glass on green epoxy without sanding. Only same day build ups. A few times I suppose, but I hate the roughness and air entrainment from it.

After 2.5 years, I think he's lost that primary bond window...

I use a clean wire brush for when I need to rough up a surface but when I don't want to sand too much.

OneWayTraffic wrote: ↑Thu Dec 17, 2020 11:32 pm After 2.5 years, I think he's lost that primary bond window...

I use a clean wire brush for when I need to rough up a surface but when I don't want to sand too much.

Wth?

How did I see that post in my unreads?

Pain killers maybe.

Sorry all.