John Melanson (john@audiologic.com)
Fri, 28 May 1999 10:32:28 -0600
Great lead on the vacuum pump - thanks!
I was trying to avoid the presure idea because I want to build a frame
without a top glass - just the negative.
It seems that this should make the dust and scratches issue much easier to
deal with. And no top glass means no attenuation of the UV byt that path.
-----Original Message-----
From: Sil Horwitz [mailto:silh@iag.net]
Sent: Friday, May 28, 1999 9:31 AM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: vacuum contact frame
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/
This archive was generated by hypermail 2.0b3 on Thu Oct 28 1999 - 21:39:35