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Old December 1st 13, 05:57 AM posted to rec.photo.darkroom
Richard Knoppow
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Posts: 751
Default Zone VI Archival Print Washer Parts

Mine is the 16x20 washer. Very heavy. I tested it using
beet juice to see how long it took for the red color to
clear. At normal flow rates, that is, no overflow, it took
too long so when I was using it regularly I put in the
bathtub and let it overflow.

--

--
Richard Knoppow
Los Angeles
WB6KBL

"Jean-David Beyer" wrote in message
...
On 11/19/2013 11:48 PM,
wrote:
Does anyone know how to control the overflow? When the
water reaches the top it pours over onto the floor. I
hope someone wil reply.
thanks,
Victoria


I have a Zone VI print washer, 11"x14" size (i.e., it will
wash prints
that size or a little larger, but not 16"x20".

The way I run it, tempered water flows in the hose
connection at my
upper right into a plenum chamber. While in there, some of
the dissolved
air comes out of solution. I wish it all did.

From the plenum, the water enters the main chamber through
to rows of
small holes; one row near the top (but below the water
level) and
another row near the bottom. After the water has washed
the prints, it
exits the washing chamber through holes at the bottom into
the exit
plenum. Picker did that because he believed hypo is
heavier than water
and it would sink to the bottom. That happens to be
nonsense, but it
does not really matter. The water rises up in the exit
plenum and goes
out the overflow pipe.

_There is no reason whatever for the washer to overflow_.
The exit pipe
is about one inch in diameter and the intake pipe is
effectively about
3/8 inch. There is little point running much over 1/2
gallon per minute
through that, since washing is a diffusion limited
process. But even if
you run a gallon a minute, it should never overflow.

What flow rate could you be running that the water comes
into the tank
faster than can escape from the large drain pipe? I have
never had it
come anywhere near the top.

The biggest problem I have with the washer is that not all
the air comes
out of the water in wintertime in the entry plenum
chamber, so some of
it comes out on the prints. I wrote to Fred Picker about
that and he
said it was not a problem because the bubbles grow in size
and float off
the prints and they do not impede washing. Well, I have
studied them and
they can remain firmly in place for over 15 minutes, and
they do impede
washing. So every 5 or 10 minutes I quickly raise each
print and briskly
reinsert it to get the bubbles off. They are caused by
mixing the cold
winter water with the hot water to get wash water the
right temperature.
I tend to do my B&W processing at 75F because I cannot
reliably get it
colder than that in the summertime, and I prefer to use
the same
temperatures all year long.

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