Use at your own risk as a way to reuse metal and save big money, or see it as an example of stupid shit you should never try. I'm not a licensed electrician and learned by getting shocks, burns and cuts. Even people working with electricity will eventually burn their house down by simply forgetting something trivial. A metal enclosure cannot burn like wood, but has an increased risk of shortening a cable.

• Tape over any sharp or metal surface where a cable might come in contact.
• Make sure that the power cable is safely anchored and cannot be damaged by the printer. Otherwise it may be scratched by the Z axis or even melted against the extruder.
• Do not leave the chamber unattended with power connected! Even a 12 volt light can cause a fire if shorted directly and it won't draw enough amperes to blow a fuse.
• Do not use any burnable material inside or outside the chamber.
• Make sure that each electric wire is well protected against metal surfaces, sharp edges and high temperatures.
• No not pull out the printer without supporting its weight. A dishmachine without its waterpump doesn't weight so much and may tip over you.
• Metal edges inside a dish machine can be razor sharp! Do not touch without gloves. Carefully sand them down and tape over if you constantly forget to wear gloves.
• Make sure that the metal case is grounded properly. Even if the electric cable is whole, friction can build up a static charge and possibly damage electronics in the printer. I got a quite painful discharge from just the mechanical friction.
• Use multiple 12 volt fans to cool the chamber by sucking air out through coal filters in the biggest hole. Use an additional air cleaner in the room or lead the dirty air outside.
• Try not to enter the room during the print of toxic plastics. Use a cheap wifi camera to monitor the progress inside the chamber from a distance. The reflective surfaces may disrupt auto exposure, so focus on the build plate. Some cameras may melt or get a bad signal unless you leave the chamber a bit open, which will leak toxic gas.
• You won't have to throttle the fans, just maximize cooling in any way you can and it will still get to 45 degrees celcius.
• Do not pull in the power cable directly against metal! The cable holder should be printed in two sets and screwed together on both sides of a hole using eight M5 nuts and bolts. Scale the model a bit if needed to fit the existing holes.
• Let the filament be fed from the printed spool holder on top of the chamber. Dish machines usually have a small hole at the top center, which was used to mount the spinner and will now be your hole for feeding filament.
• Use a digital thermometer to check the ambient temperature. I built mine with power sockets for fans and light so that all use the same power supply.
• Don't do all this if you can afford a well built enclosed 3D printer, which already have all these features with more safety.
• You might want an all metal hotend upgrade if using this chamber, otherwise the PTFE heat insulation tube will swell until the filament gets stuck from the higher temperatures.