I have finished my Halo Reach EVA helmet and now I have cut out the visor already so I decided to head on to vacuum forming. because my oven was so small I had to cut the sheets down to about 15 x 20" . The sheets I use to vacuum form are 1/16" Petg sheets. I have been cooking the sheets for maybe 15 mins at about 225 Degrees Farenheight and when it starts to sag about 3-4 Inches I would pull it and put it on my vacuum form rig. It just doesn't cover the whole buck or wrap around the edges like I imagined it would. I am just using a regular old shop vac and I really couldn't tell y'all the details on that but I just want to know what I am doing wrong. It almost seems like the plastic isn't melted enough to be able to wrap around it and I was thinking maybe I need to let it sag more or cook it at a higher temperature for a shorter time. I am unsure and I only have one sheet left and would like any advice I could get from people who have experience with this sort of thing. I will post pics later when I get home of some failed attempts.