Compressors for vacumpump

[Pandrone]

I am going to make a vacumpump out of a compressor. The compressors i have in "stock" is Danfoss: FR7,5A, NL6A and 2x TL4A. So which of these should i use? Btw, i was planing to make a GPU direct die out of the FR7,5A. So i have to choose from the other three. I could make a 2stage vacpump with the two TL4A compressors but they are a bit weak aren't they?

I think i pretty much know how to make a vacpump, i have to braze a schrader/piercingvalve to the suctionline. Then it's ready or?

[Gary Lloyd]

For a vacuum pump, a smaller compressor is better than a bigger compressor (smaller valve ports). An R134a/R12 compressor is better than an R22/R502/R404A compressor (smaller valve ports). And a low temp/LBP compressor is better than a high temp/HBP compressor (smaller valve ports). Bigger does it faster, smaller does it better. A real vacuum pump does both, but it is expensive.

[Pandrone]

Thanks for the input Gary, you took up everything i needed to know :). Or just one thing, the TL4A is a small compressor 1/8hp. Two of these in a "2stage" vacpump, would that be good? Well, if it's not too bad i'm going to test it out.

Edit: The NL6A is a LBP compressor, maybe i should go for it.