Pure speculation but: I'm thinking a torch may heat the surface too rapidly and unevenly without letting the heat get deep enough into the plastic.
Let us know how that works out. I'm just guessing, but maybe an oven would work out better. When I boiled one it took quite a while at a full rolling boil and a couple of tries to get it hot and pliable enough to where I could force the broom handle into the channel to open it up.
Good Luck and keep us posted on your project.
BHJ
Bookmarks