Today is a pretty technical blog posting, so if the gory details of the Superman Returns cape build bore you, I suggest you take your droids and move along.
I called up Smooth-On tech support a while ago, and they recommended this stuff to me.
Brush On 50. The "50" is the shore strenght, so this stuff is pretty flexible.
When I called smooth on, what I really wanted was something I could brush into a silicone mold without having it "pull back" from the silicone. This is a problem I have with almost everything I brush into my mold. The guy on the phone recommended this stuff. When the sample kit arrived, I did some experimentation.
I brushed a couple of samples onto my 1630 positive of the cape material. One of the applications was done to a prepped surface, the other application was not. The prep was basically a few blasts with mold release spray.
And also some directly onto the cape mold. What was REALLY nice about brushing it into the mold is that it did not pull away AT ALL, which made me really happy. Even when I brushed it on very thin, it still kept in place.
Here are the results from the cape. It's kind of hard to tell what is going on here, as the brush on has fused with some previous tests that I never peeled off the cape. The punchline is that it's VERY nice. There are NO bubbles. It really took to the mold really well, even on the thinnest of brushings. This makes me very curious about what can be accomplished with this stuff. I believe further tests are in order.
Here are the results from my 1630. Again, ZERO air bubbles. Both turned out VERY nicely, however, for the section that was untreated, the urethane bonded just a little too much, and it was damaged when I tried to remove it. The lesson learned here is that I will need to spray rigid molds with a release agent prior to brushing the stuff in. The good news is that this product works REALLY well.
I only have a few nits about this particular product. From the one time I used it, it didn't take pigments very well. I squirted in a bit of So-Strong tint, and it didn't really penetrate very well. I thought it would have made it much more "red", but instead it kind of turned pink. I also dropped in a bit of black, which served to make the stuff look brown. Which is also an interesting lesson. The stuff becomes a bit too thick to work with after about ten or fifteen minutes, so if I do anything of size, I will need to work quickly. Not a big deal really, as I believe I could do multiple brush-ons and they would fuse together well.
Also of note to other hobbyists is something new I have started doing. I picked up a college rule composition book from Target, and I'm using it sort of as my R&D bible. All of the lessons I learn from my various experiments are going to be logged in this book. It is great that I have my blog to refer back to, but it would be nice to have detailed, precise, and boiled-down information all in one place. I have a separate page for each material that I experiment with, and a separate page for each part of the suit I am working on. It's kind of like a recipie book, so that I don't have to keep doing the same experiments over and over again, and so I can keep track of my lessons learned. It seems like a good idea to keep track of this stuff, and it's already proven pretty valuable.