what's the coolest temperature you would fiberglass in?

sluggo · Post by **sluggo** » Tue Mar 25, 2008 1:43 pm

I'm all set and pumped to start pre-coating tonight and fiberglassing tomorrow. However, the cruel hand of fate has once again dealt its hand and the temperatures have plummeted. I think I can get the shop 16°C. I've glassed at this temp before but I also know that it is easier to glass above 20°C. I've also already enlisted help for tomorrow night. What is the lowest you would go for fiberglassing?

cheers

Tim Eastman · Post by **Tim Eastman** » Tue Mar 25, 2008 2:14 pm

A lot of that answer will depend on the epoxy you are using. I used System Three SilverTip Laminating and absolutely fell in love with it. It's about the coldest I've found as far as workable temps.

The tech data SAYS it will go down to 35°F - how that pans out to Celsius I'm not sure. But that's pretty dang close to freezing.

I would never try that cold personally.

sluggo · Post by **sluggo** » Tue Mar 25, 2008 2:30 pm

Yeah, I'm using the Silvertip. I've used the regular S3 epoxy down to 12°C (54F) and the silvertip is less viscous.

Tim Eastman · Post by **Tim Eastman** » Tue Mar 25, 2008 5:19 pm

Sluggo I would seriously consider doing a test batch at those temps, with wetout and fill.

But I would also be most interested in hearing your test results if/when you do that.

sluggo · Post by **sluggo** » Tue Mar 25, 2008 9:04 pm

Hi Tim,

I decided to not do any glassing. The weather has turned really foul and it's not worth the headache of working in cooler temperatures. However, I can relate some experiences when I built a s&g kayak two years ago. I was using System Three regular epoxy. Some of my gluing was done at 8°C and the epoxy cured just fine. For the hull I worked in temperatures from 12°C to 16°C. Again, the epoxy cured just fine within 24hrs. If I recall correctly, the epoxy passed the "green" stage at around 8hrs. There were a couple of spots that turned cloudy while the epoxy cured (or close to the time that it was applied) but those areas totally went clear later on. I was using the fast hardener and to the best of my knowledge I didn't get any blush - certainly I didn't feel or see any film and subsequent coats of epoxy went on just fine. For the deck of the kayak I used Silvertip at much higher temperatures, probably close to 24°C.

In terms of final product I don't think anyone would be able to tell that the hull was done in cold temperatures while the deck was done with Silvertip in warm temperatures. And although I know firsthand that Silvertip is clearer than the regular resin, in the final product you really can't see any effect of the tint. From my experience, the warmer temperatures greatly affect the useability of the epoxy. Simply put, the Silvertip and warm temperatures just make it a lot easier to apply. The Silvertip also sands better imo.

I've read that for the clearest wetout and best way to remove any signs of glass flecks is to use thin epoxy and warm temperatures. Again, while this improves the useability in my experience both warm and cold, thick and thin can give the same results. Both my deck and hull show some flecking from the glass underneath (for trained eyes only!). My conclusion is that this is a product of the fiberglass itself. Speaking with System Three, they came to the same conclusion. They said they tested their epoxy under many conditions and any glass flecking or showing was due to the fiberglass itself. Mind you, System Three sells epoxy, not fiberglass... :rolling eyes

Tim Eastman · Post by **Tim Eastman** » Wed Mar 26, 2008 5:17 pm

Sluggo - it sounds like we are using two different types of epoxy but very similar. But thank you for your observations and reports.

System Three adamantly proclaims that the System Three Silvertip Laminating epoxy will not blush. I have not worked in the temps that you have but I have not had a single blush or orange peel problem what so ever.

Thanks for your feedback!

sluggo · Post by **sluggo** » Wed Mar 26, 2008 10:23 pm

Yes, just to be clear:
I used S3 regular epoxy on the kayak hull (cool temps, no blush)
I used S3 Silvertip epoxy on the kayak deck (warmer temps, easy application)
I'm going to use S3 Silvertip for the canoe

Arctic · Post by **Arctic** » Sat Mar 29, 2008 7:39 am

I regularly use West System starting out at about 17C and finishing at about 12C
Seems to work well

Mark