Dan, I think that's what it said on the spec sheet. I know I filled them, then had to let them set over 24 hours before they were cured.
I know there are some good products on the market for doming, and the sample I had might not have been a good match for that type of stuff. It was a free sample, so I didn't know much about it. I had heard that the good stuff was quite expensive, and I was only looking to play around with a few things, so I just used what was sent.
On the other hand, the UV stuff they sent, I couldn't get to cure at all under UV light. I actually left it under UV light for 2 days and it was still sticky. Not sure if it was bad or if my UV light wasn't strong enough, but I couldn't get it to cure.
I've been told that the better materials do really work well. I've never tried anything but the free samples, so my experience is basically zero, I'm just reporting what I tried.