Hmmm....I've always had really good success with shrinky dink stuff and it's
one of my students' favorite materials.
Shrinking it with a heat gun?? I've always used a toaster oven, at 300
degrees for about 2-3 minutes. (I bake them on a piece of brown paper bag
on top of the metal tray that comes with the toaster oven.) I've always
ordered directly from http://www.shrinkydinks.com
It's got to curl up. I guess that's part of the shrinking process and I
used to freak when it happened. Now I usually wait it out and it'll flatten
on its own. When I get it out of the toaster oven, though, I use a hot mitt
to flatten it further.
One thing I found, though, is that if you try doing a big piece (8x10),
you're more likely to get things that become curled and stick. (Of course I
haven't TRIED baking big pieces recently, so it might actually work out...)
I start with pieces that are about 4x5 and even if the kids cut them out
into tiny, irregular shapes, they curl then straighten.
I've found that colors DO tend to get brighter....I like using Prismacolor
but I've also used just plain ol' crayola colored pencils. And if you use
ultra fine point sharpies to enhance details, they look really cool when
they're suddenly miniaturized.
Again, I think you NEED to use a toaster oven (consistent temp rather than
heat being applied unevenly), watch it curl, twiddle your thumbs, and wait
it out to see if it uncurls (up to 3-4 minutes, if necessary), and then
flatten with a hot mitt....
As a side note, one kid got into the idea of making all these neat shapes
and taking them out of the oven BEFORE they completely flattened. He was
fascinated with these little non-objective "sculptures" that he could
create. (This senior, by the way, was recently accepted to art school!)
So anyhow, don't give up on it yet--try a few more on your own before
getting the kids to try them and let me know how it goes!