RE: [ATM] Tooling Up For Carbon Fiber

["Donald Good" <donald.good@comcast.net>]

I found that the 0522 should reach -26" Hg vacuum in continuous operation.
I couldn't find product info at Gast for the 0522, but there is for the
0523, which I assume is an equivalent current model (same vacuum and cfm
numbers)
http://www.gastmfg.com/pdf/23_oilless_OM.pdf
Therefore I also assume your pump is used.  The vane life for the 0523 is
5000-15000 hrs and yours might be reaching that range.  The bearings might
also be wearing out which would account for an initially higher vacuum while
the bearings are still cool, followed by a drop as they heat up, increasing
friction and decreasing rpm.

If it were a matter of a leak, you would not get this peak and drop, just a
rise to a lower than expected max vacuum.

Also note that the max gauge reading cannot exceed your current local
atmospheric pressure.  In general, a pump will achieve a vacuum that is a
constant short of a total vacuum.  Since the std atmosphere is 29.92" Hg and
the 0522 reaches 26" in the std, I would expect the max gauge reading should
reach abut 4" less than your current local atmospheric pressure.

And yes, that is enough for vacuum bagging.
Don


> -----Original Message-----
> From: Rod Shea [mailto:RodShea@comcast.net] 
> Sent: Thursday, April 21, 2005 5:40 PM
> To: Donald Good
> Subject: Re: [ATM] Tooling Up For Carbon Fiber
> 
> Donald,
> 
> Thanks for the reply.  The pump is a Gast 0522 rotary vane 
> pump with a 5 amp 115VAC motor.  The vacuum gauges I am using 
> are automotive type, and show the vacuum to be -26, if I 
> attach it directly to the pump.  I thought the units were 
> Torr, but they are really inches of Hg, makes a big 
> difference, my error, <G>.  The gauge goes to -29.  This is 
> enough for vacuum bagging, is it not?
> 
> Thanks,
> 
> Rod
> 

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