I needed a acrylic plate that is 90cm long and is bend 90° over the ling side. For this I requested some quotes from various suppliers. They all came in at about €100 to do this. Therefore I decided to invest the €100 in a DIY bending jig, this way I can also use it in future projects.
After some searching in my scrap-parts bin I came across a heater resistor from a clothes dryer.
I cut of the ceramic isolators and mounted the resistor wire between 2 screws. Around this I build the bending part. This consists of a fixed board and a board on hinges.
I added some aluminium foil that is covered with a layer of kapton isolaton tape to protect the wood against the heat
An extra board is screwed on top to fix the acrylic sheet.
The device can be used like this, however it gets too hot and may discolour/warp the plastic. Therefore I added an PID controller to control the temperature of the wire. In the center I stuck a thermocouple sensor to the resistance wire.
The messy inside of the controller box:
A videoclip of the bender with a polycarbonate plate:
(I also heated from the top with a heat gun, this to get it hot faster. This may not be necessary, however I have not tested yet without this.
When copying this design please not that the resistor wire is connected to mains, and therefore is not safe. To use this more safe a isolation transformer is recommended.
- Clothes dryer heating resistor
- Digital 220V PID REX-C100 Temperature Controller + max.40A SSR + K Thermocouple
- K Type Thermocouple Probe Sensor For Digital Thermometer (Lower thermal mass than the one supplied with the controller)
- mains switch
- Enclosure, for example: Link