Plastic welding?

What PSI is a refrigerator compressor? I got 2 and they both put out some form of air pressure from the vacuum discharge port. I use one for pulling vacuum on the A/C manifold. They are almost free when you see a scrap refer in a back alley. 2 nuts and dikes on the lines and its out.
1/5hp compressor ~85psi & ~.7cfm (refer)
1/3hp compressor ~115psi & ~1.1cfm
1/2hp compressor ~115psi & ~2cfm