<< I have in the past done some collotype print making, my printing press was
an old domestic mangle used to wring out clothes, I sheathed the the
rollers in steel pipe and bingo an instant printing press, unfortunately
this great printmaking machine did not like glass plates the preferred
substrate, and I had a cracking time until I cameto my senses, >>
I had pretty much the same idea. I bought mine from a place that has
supplies for car washes and used it pretty much straight out of the box. I
didn't have any trouble with glass breaking using 1/4" plate glass. Also the
advantage to glass and I guess the reason it was picked originally is that
you can do a brief exposure from the back. This seemed to help the delicate
highlight tones. Although it has been a while, some of the most fun I have
had with alt-processes was with collotype. Also at the time I was doing
bromoil transfer and collotype was much easier.
Bernie
Bernard Boudreau