Hey there! I have a project for which I am making custom lampshades. I plan to laser cut acrylic sheets into 20cm x 40cm rectangles, and then heat them gently in the oven to soften. I'll then form them around an aluminium cylinder.
I have done similar using a heat gun and a cubic wooden form, slowly softening the plastic at the corners and pressing it into shape (wearing gloves of course). This worked great. As this project I am making cylindrical lampshades, the whole sheet of plastic will need to end up curved, so I think heating it evenly in the oven will work, plus they are smaller pieces and the previous project would not have fit in the oven.
The plastic I am using is 5mm reeded acrylic, shown here -
https://www.sheetplastics.co.uk/5mm-reeded-clear-acrylic-sheet-cut-to-size
The diameter of the aluminium mould is 90mm with wall thickness 5mm.
I would heat the sheet of plastic flat on a clean baking tray, with greaseproof paper underneath. I would then lift the plastic out, and using gloves, lay it over the round form, and press it into the curve. I could hold it until it cools down, or wrap in tape or elastic bands for example.
I am wondering what temperatures, and for how long, would people suggest heating the plastic. And if there are any other considerations.
I am also wondering if there's any chance of the plastic clouding with heating. I have used the exact same plastic on the previous project but again I just heated it locally with the heat gun rather than globally with the oven.
I will be making 4 lampshades, and I have 5 pieces of plastic, so one spare.