Re: Stability of dichromate solutions (and its use in gum)


FotoDave@aol.com
Wed, 13 Jan 1999 19:19:01 -0500 (EST)


In a message dated 1/13/99 4:06:01 PM Pacific Standard Time,
sanking@hubcap.clemson.edu writes:

> There seem to be few carbon printers around so I post these details at the
> risk of boring many on the list. However, here goes . . .

Sandy,

Thanks for the details. I am sure many will benefit from them. I told myself
last summer that I was going to try carbon this winter, but I am not sure if I
can get to it due to other works. Maybe I should go to Montana to take a class
from you. :) It will be a chance to meet Judy too. Oh, but I think the times
are not the same since it's a whole summer program rather than a short period
of time like APIS.

> 2. I also keep on hand bottles of fresh stock solution, mixed with
> distilled water and stored in glass bottles at room temperature, in the
> dark.

What is the concentration of the stock solution? Is it saturated? I am still
trying to figure out why my dichromate solution precipitated (and it
precipitated badly. You can clearly see a layer of brown precipitates). As I
said, I am suspecting the change of saturation point due to temperature, but
it could be other reasons.

And I must confess my sin here. I did not use distilled water in preparing my
dichromate solution. :P :) That could be the main problem too.

Dave



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