Great article by Seiichi Inoue of www.hobby-elec.org. The article goes thought the process of building a bender to bend acrylics sheets. Perfect if you need to create project boxes or even custom computer cases. This information on this website is well presented and challenging. The bender is basically an aluminum square tube with a electric filament going through the center. The circuity controls the whole process and protects the circuit in case of a failure. I have seen generic benders on the web, but this is by far the most professional.