From: Joe Portale (jportale@gci-net.com)
Date: 04/23/02-01:31:12 PM Z
Thanks Sandy and Carl,
Actually it seems that this potassium carbonate is bad. It is a new batch
that was picked up from a local chemical supply house in town. The security
band was still on the jar, so we could assume that it will be okay. I just
checked the liquid B standing in a covered beaker, it has seperated again
and turned a lavender color. The mixing vessel was clean and spotless, so
something is amiss. I'm taking the stuff back for a different lot number. I
have a pile of film to get done, so I need to get cracking and worry about
the analysis later.
Joe
----- Original Message -----
From: "Sandy King" <sanking@CLEMSON.EDU>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Tuesday, April 23, 2002 8:28 AM
Subject: Re: pyrocat part B question
> Another thought. Potassium carbonate is known to absorb water readily
> from the atmosphere so that if you store it in a damp environment it
> absorbs a lot of water and becomes much heavier for a given volume. I
> wonder if the opposite might not happen in your environment? That is,
> in the desert with low humidity perhaps the chemical will lose water
> to the atmosphere, making it weigh less per volume. I don't know if
> this is possible but if it is there might be an explanation as to why
> you are unable to make the 100% solution. Maybe someone who knows
> more about chemistry could comment on your problem.
>
> Sandy
>
>
>
>
>
>
> >Joe,
> >
> >Potassium carbonate is soluble in water up to about 125-135%, which
> >means that you should be able to dissolve at least as much as 125g
> >in 100ml of water. I have been working with this formula for about
> >three years and have never had any problem in mixing the 100%
> >solution. I add the potassium carbonate slowly to the water because
> >there is quite a lot of heat produced from the mixture. It should
> >dissolve completely in 30 minutes or less.
> >
> >Sandy
> >
> >
> >
> >
> >
> >
> >>Okay folks, I give, how do you keep 100 grams of the carbonate dissolved
in
> >>100 mls of water? It has been three days and the best that can be said
is
> >>the "B" is a slurry. For the record, the chemicals are analytical grade
and
> >>the water is distilled. I have been using the 10% solution B and
watching
> >>the threads on this subject decided to try the 100% solution.
> >>
> >>How about this as an alternative, since the formula is calling for
1:1:100
> >>(or 2:2:100 depending what one is doing), and the 100% shows B actually
> >>being 1 gram of pot carbonate per 100 mls of water, why not add the
> >>appropriate amount of dry carbonate to the working solution. If my logic
> >>works out right, that would be 10 grams per 1000 mls of working
solution.
> >>Just mix the appropriate amount of carbonate to the water then add the
A.
> >>OTOH, why not mix up a big batch of 1% carbonate and add the part A as
> >>needed? Does the carbonate keep? in solution? Does this sound feasible?
> >
> >
> >--
>
>
> --
>
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