What is the best way do build a vacuum. Are there any heat related issues? What parts does one need to build a good vacuum? How much power do they draw? Please let me know, thanks!

Moved to Rules/Strategy

You can make a simple vacuum by pulling a piston with another mechanism. This is good for things that make a seal, like suction cups.

^^ Yes. For small volumes, pull on a cylinder.

If you want to move larger volumes, the most common way is to find a vacuum cleaner of the appropriate capacity (and preferably the same form factor as a legal motor) and swap out the motor. This topic has a few references you may want to investigate:

You can also use the venturi principle in conjunction with the compressor. You can get considerable vacuum using this mechanism and it’s very reliable. It can also be controlled via the PCM to give you suction when you need it. Just search for “venturi vacuum” and you’ll find a lot of examples and units for sale. We’ve already verified they can hold the hatches. They will also hold the cargo, although the cargo is more difficult to get a good seal on because of it’s pliability.