Surplus Gast pump?

[Dan Forman]

I've been looking through the vacuum chuck threads, and seems like most of you have the 0523 gast pump from Surplus Center. http://www.surpluscenter.com/item.as...tname=electric

I'm curious though, as this link lists the max vac as 20" HG, while in previous threads, folks were talking in terms of 25 to 26" pull. Am I missing something? Is this a mercury/water thing, both liquids being used to measure vacuum?

Other questions, how much noise do these things make, and how many of you go through the recommended shut down process, which takes about 25 minutes according to the manual? Do the filters act as mufflers, or are there separate mufflers available as well?

Dan

[Paul Andrews]

I'm curious though, as this link lists the max vac as 20" HG, while in previous threads, folks were talking in terms of 25 to 26" pull. Am I missing something? Is this a mercury/water thing, both liquids being used to measure vacuum?

Other questions, how much noise do these things make, and how many of you go through the recommended shut down process, which takes about 25 minutes according to the manual? Do the filters act as mufflers, or are there separate mufflers available as well?

Dan,

I use one of Surplus Centers pumps, and they are a great value. The max vacuum generated is 26" at the headstock. As to the noise, you know that it is running but the level of noise is not objectional. I never heard about a proscribed shut down procedure and therefore have never follwed one. When I'am done I turn off the pump. I do run a filter on the exhaust port for two reasons. One is to suppress excess noise and the other is to filter out the graphite powder generated by the vanes in the pump.

[Tom Steyer]

I regularly pull 25 in/HG with this same pump. I also have not heard of a shut-down procedure - like Paul, when done I just switch off the power. Dan, perhaps you could share your source for this shut down routine? Paul, how long have you been using this pump - I have only had mine for a couple of months. I run an intake filter at the pump, and the small bronze wool filled silence that the Surplus Center sells.

[Paul Andrews]

Tom,

I purchased mine about a year ago.

[Ed Scolforo]

Look in your manual or on line. It specifies proper shutdown procedure so as to prevent overheating the pump.

[Dan Forman]

I found out about the shutdown procedure while researching last night.

Here is a link to the GAST page where you can download the manual. Scroll down to rotarty vane manuals, and click on the 23 series, or try this link, it should work. http://www.gastmfg.com/pdf/OM/23_series_oilless_om.pdf
Apparently this procedure will prolong the life of the pump, or at least put off a rebuild.

Well, I just ordered one, been wanting to get into vacuum press veneering, so this will do double duty. I asked the tech guy at SC about the pull question, he just said that they are rated for 20" of mercury, and that they made a very large purchase some time ago, and that these are all from the same supply.

Dan

[Steve Schlumpf]

Thanks for the info Dan! Been doing some thinking about getting into vacuum chucking and any additional info helps!