I want to try vacuum infusion but I need to do it at the minimum cost which leads me to my question.
When do I need a pressure pot and when can I forgo one?
It’s as important as the vac pump in that if you don’t have one and you suck resin in to the pump once its trouble.
It doesn’t have to be an expensive pressure pot either. Any pot or container that you can seal air tight and won’t implode with a feed in and a feed out will do the job.
what Galway said…
It’s an important part of not getting resin in your pump. Also, yes, as long as the jar has a seal, and strong enough to hold up to 14.7psi atmospheric pressure, you are good. Many ppl use barb fittings on the lids of old food jars. If that has a good gasket, you are good to do with no additional sealing needed!
And no, don’t underestimate the resin flow…even if you clamp the resin before it hits the vacuum line, depending on your resin, cure temps, etc, it can flow all the way down a 3ft line into your bucket.
So pressure pot = catch pot?
If it’s just a bucket that can withstand atmospheric pressure why do people pay 80+ dollars for them then? Is there something I’m missing?
Try pulling a vacuum on a sealed bucket. 
For similar results, try parking a Mack truck on it!
Point taken
Thanks!
Glass jar with strong lid sealed shut (coffee jar over here).