Mac42 (Feb 01, 2001 06:37 p.m.):
I'll probably get some disagreement on this, but silicone is not a good thing to use. Think about it... after you apply it you have to wait for it to solidify... and what makes it solidify is contact with air. In order for the silicone on the inside to do this there has to be a certain amount of air that can seep into it, otherwize you would have a very thin layer of non-liquid on liquid silicon.
Why's that bad? Well, air contains water vapor, and air isn't going to go through and leave the vapor behind. If the cold part is really cold, then very slowly water collects inside... the only thing is that the silicone is water-proof, so it doesn't get back out... basicly your insulation turns into a very slow water pump, which is what you were trying to avoid in the first place.
Feel free to disagree with me, especially since I don't know of anything better to use (I used a plastic bag... now that was funny looking). Have fu n, and i hope it works out.