# Vacuum



## greenchicken (Nov 11, 2012)

I decided to start a separate thread just for vacuum pump for stabilizing.

Can some explain the pros and con  between A pump such as the Gast Vacuum for $449 and the Holdfast Vacuum Generator for $159?

I do have a compressor which I understand to be necessary for the Hold Fast.


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## Bigj51 (Nov 12, 2012)

Not familiar with either one of those, but I have a dual stage Mastercool which will pull down to 15 microns. It works extremely well and gives me perfect results for my stabilization process.


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## MesquiteMan (Nov 12, 2012)

If you are looking for a vacuum pump for stabilizing, your best bang for the buck is going to be a rotary vane, oil filled pump.  Gast makes a great pump but they are more for moving more air at a medium vacuum.  In other words, they just do not generate a deep enough vacuum for good stabilzing.  This is a pretty descent pump for the money:  Robinair 3 CFM  I have one of these as a backup and carry around pump for demos and it does a fine job and is only $100.

The Holdfast pump you mention is a venturi type pump and requires a fairly big compressor to keep up.


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## trapper (Nov 12, 2012)

A friend of mine made one up using an old pressure cooker and a compressor from a freezer. I'll try and get details from him or a "how to" and post it.


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## MesquiteMan (Nov 12, 2012)

Yeah, I forgot about the refrigerator compressor as a vacuum pump.  It is quite simple, actually.  You just need to wire it so that it runs.  Then, turn it on and check the two copper tubes that were cut to remove it form the fridge.  One will be blowing and one will be sucking.  Get the proper fittings to connect a hose to the one that sucks and connect that to your vacuum chamber.  I have one that I did just to experience it and it does a pretty good job.  It does not produce as good of a vacuum as my real vac pump but it is good enough for descent stabilizing.


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