G’day. Don’t use a torch; acrylic has a very low heat conduction
coefficient, so the face where the flame hits cooks up to bubble
heat quickly and the other side is quite cold.
Simply heat a household oven to about 70 - 80C, place the sheet (or
whatever) acrylic plastic, in it and it will soon become very
rubbery and can be handled with gloves and manipulated to any shape
you want. I have even made tube, angle, or half spheres with hot
acrylic. For spheres I clamped the 1/4 inch thick hot sheet on a
strong airtight box with a suitably sized hole in the top. I quickly
extracted air from within the box using a vacuum pump until the
atmospheric pressure pressed the flat sheet into a half sphere. I
cooled the plastic down with the vacuum in place using a gentle
blast of cold compressed air until it went solid. I cut off the
extra plastic and two of the half spheres were glued together with
acrylic cement. I used this technique to make atomic crystal models
for lecture demonstration to 300 students. The ‘crystal’ models
were nearly 24 inches square, transparent, and light enough to hold
up high with one hand.
Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ