Re: vacuum contact frame


Sil Horwitz (silh@iag.net)
Fri, 28 May 1999 11:31:02 -0400


At 99/05/27 09:33 AM -0600, John Melanson wrote:
>I'm going to try to make my own vacuum frame, a really light one made out of
>plexiglass. I was sondering if anyone had done such a thing. Also if
>anyone knew a supplier of vacuum pumps that could be had without breaking
>the bank.

The best supplier for mechanical and electro-mechanical devices at decent
prices is Surplus Center, 1015 West "O" St., P O Box 82209, Lincoln, NE
68501-2209, phone 800-488-3407. They have an Oilless Vacuum Pump (4 CFM) for
$69.99, their item number 4-1421. For your purpose (as, indeed, for all vacuum
pump lab uses) to have an oilless unit, but this pump is truly overkill.

My suggestion is to try to find an aquarium pump (pet stores, aquarium stores)
for just a few dollars, that has both an inlet and an outlet. You can use the
inlet for vacuum, as that will provide more than enough to hold the small minus
pressure you need. Alternatively (and to me, more desireable) is to use the air
output to force a positive pressure to press a flexible backing against the
glass-neg-paper "sandwich" as it is easier to get even pressure positively than
through a vacuum, which requires an air input evenly over the surface, a
precision requirement. With pressure, precision is not all that critical. And
an aquarium pump (diaphragm or piston) will do the job.

Have fun. The fun IS experimenting!

Sil Horwitz, FPSA
Technical Editor, PSA Journal
silh@iag.net
Visit http://www.psa-photo.org/
Personal page: http://www.iag.net/~silh/



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