opinion needed for vacuum pump please

[David DeCristoforo]

"True high vacuum levels are measured in sub micron levels..."

This is getting into the same "hair splitting" zone as worrying about measuring in thousandths of an inch. It's just nor relevant. Any pump that can draw 25 inHg (12.5 PSI +/-) and move a few CFM will be adequate for most applications. More is, obviously, better but you cannot get a whole lot better. Like I said before, the best I have ever gotten from my vacuum system is 27.5 inHg or approximately 13.75 PSI.

[David DeCristoforo]

Look again. The listing says:
1/4 HP Rotary Vacuum Pump/Compressor
Used, GAST model 0522-P335-G509DAX.

Also rated at 20 in. Hg max vacuum.

New Gast pumps start at around $250 although you can get them for a bit less from some discount suppliers. But the "good" ones start at around $450+

[Bill Arnold]

"True high vacuum levels are measured in sub micron levels..."

This is getting into the same "hair splitting" zone as worrying about measuring in thousandths of an inch. It's just nor relevant. Any pump that can draw 25 inHg (12.5 PSI +/-) and move a few CFM will be adequate for most applications. More is, obviously, better but you cannot get a whole lot better. Like I said before, the best I have ever gotten from my vacuum system is 27.5 inHg or approximately 13.75 PSI.

Good point, Dave. I have my system set to regulate the vacuum between 18 and 22 inHg. I recall one curved assembly on which we were applying veneer and had to tape the vinyl sheet over it. Try as we might, the maximum we could get was 8inHG but the veneer was still sucked tight to the substrate and adhered perfectly.

Higher vacuums are advisable for bentwood laminations, of course. My system with its average of 20inHG will draw nine 1/8" layers tight to a form of 12" radius long before it reaches its cutoff point.

[Chuck Wintle]

thank you for correcting me. it produces about 28 hg steady however I do hear some rattling inside the motor. the guy let me check it out before I buy it.

the rattling noise is probably the vanes on the rotor as it spins. Probably not too much to worry about. The better pumps i have tested at work go to between 100mTorr to, as low as, 20mTorr or 0.001377956 inches of mercury. The oil vapor is common with these pumps and is more pronounced when the inlet is at atmospheric. These pumps are not hard to rebuild, kits should be widely available.

[Steve Rowe]

Look again. The listing says:
1/4 HP Rotary Vacuum Pump/Compressor
Used, GAST model 0522-P335-G509DAX.

Oops. I stand corrected. I wondered why the price dropped about $35 from what I paid several years ago.

[Jeremy Yorke]

Thank you guys for your wonderful and very useful informations.
The more I read your responses the better I feel about buying it. Bill I am very impressed buy your vac. press station. All the rest thank you for enlighting me I am gonna buy the pump and rebuild it and then I will build a press, this will be my winter project. Now, let me enjoy reading few articles regarding this subject from joewoodworker dot com and hopefully I will come back and post some pictures.

[Bruce Wrenn]

Thank you guys for your wonderful and very useful informations.
The more I read your responses the better I feel about buying it. Bill I am very impressed buy your vac. press station. All the rest thank you for enlighting me I am gonna buy the pump and rebuild it and then I will build a press, this will be my winter project. Now, let me enjoy reading few articles regarding this subject from joewoodworker dot com and hopefully I will come back and post some pictures.

If it pulls 28" hg, then why are you going to rebuild it? These things are made to run for hours on end, often for 24 hours straight. It takes a lot of time to evacuate a large system. I have a couple that are over 20 yers old.