What will multiple vacuum pumps do to a vacuum system, namely to PSI?
Long story short, I'm looking to make a vacuum forming table, and have most of the thing designed. However, I am looking to use two (maybe three) cheap vacuum pumps until I have the money to get a decent vacuum pump. I know that the pumps (4 CFM) if stuck in parallel will get me roughly 8 CFM, however, what will that do to the PSI? The pumps have a 90 PSI pull (if thats the right phasing to it) and I'm unsure what grade of pip/tubing to get for this. Thanks in advance!!