Damn, that's quite a lot of bubbling! It seems that it's probably mostly caused because of the vacuum causing the resin to start evaporating, or causing some trapped gas to come out of solution. Very interesting. I use positive pressure in my casts, so I wont have that kind of problem. Do you have a pressure pot?
mangozac wrote:You really shouldn't be having that problem, even without the post curing. Then again, I imagine the temperature is getting pretty cold where you are so maybe there's just not enough heat being generated by the reaction? How precise are you mixing it (make sure it's 1:1 by volume or 10:9 by weight)?
Yeah, I use a small graduated cup to measure out the parts by volume, and I'm quite accurate with that (I have some chemistry experience.
It's wasn't really a major issue. I just noticed that some of the pieces I've cast with comparable thickness to some models I have from Forgeworld have been much more flexible. They seemed to hold more of a "rubber" kind of characteristic, as I could bend them, and they wouldn't fully return to the original position.
Anyway, I did a test last night. I took some pieces I had cast a few days ago and put them in a bag, as well as the pieces I cast last night, which I immediately put in another bag after demolding.
I submerged both bags in a water bath at 65C for about 3-4 hours.
The bag with the older casts leaked, so water was in the bag, so I don't know if it was the water or the fact that they've been left for a few days, but either way: The went like rubber... Like, I could tie some of the pour reservoirs into a knot. They were still flexible this morning.
The bag with the fresh casts didn't leak. I noticed that within 5 minutes of removing them from the bag, they were rock hard. There was a notable improvement on their ability to hold shape permanently. They acted much more like the solid resin from forgeworld does.
So in future I think I'll definitely be post curing these casts at 65C for a few hours.