Dry Ammonium Thiosulfate

MurrayMinchin · Jan 20, 2006

Hi there,

I've heard people mention here that they have used dry, crystal, or granular ammonium thiosulfate. Where can you get it in Canada? In the U.S.? I'm trying to avoid the cost of shipping water thousands of miles.

It must be viscious, nasty stuff...mix outside - long rubber gloves - eye protection - respirator rated for such stuff...anything else I should be aware of IF I can get it?

Thanks.

Murray

titrisol · Jan 20, 2006

Ammonium thiosulphate can't be worse than ammonium bicarbonate used in baking (regarding viscious, nasty, whatever)
I'd go for granular, since that would be easier to pur and less airborne powder which is the one that smells bad.

The simplest way to mix this would be to put the powder into a piece of cheesecloth to make sorta teabag and let it dissolve by itself.
It may take a couple of hours but no powders flying everywhere, and no need for respirator and oxygen mask.
It also helps to work in a moist environments instead of a very dry one to keep the powder to go airborne too much.

ann · Jan 20, 2006

try jdphotochem.com they are a Canadian company

nworth · Jan 20, 2006

It's a pretty ordinary white powder. The problem is that it is hygroscopic, and you are never sure just how much water it has absorbed. That makes measurement impossible unless you have kept it scrupulously dry.

Gerald Koch · Jan 20, 2006

Some years ago I had a similar idea to buy anhydrous sodium thiosulfate and not pay for water in the pentahydrate. Unless I was very careful the anhydrous stuff would absorb enough moisture to set like concrete.

Lowell Huff · Jan 20, 2006

Dry Amm Thio is available at your local plant nursery as SULFATE OF AMMONIA, grass fertilizer.

Photo Engineer · Jan 20, 2006

My suggestion....

Don't use dry ammonium thiosulfate.

Kind of like buying a pound of phlogiston. Not very reliable. ~smiles~

PE

srs5694 · Jan 20, 2006

Photo Engineer said:
Kind of like buying a pound of phlogiston. Not very reliable. ~smiles~

For those not up on the history of science, a brief description of phlogiston can be found here, among other places:

http://www.infoplease.com/ce6/sci/A0838824.html

Briefly: It's part of a discredited 18th-Century theory of combustion; combustible materials were said to contain plogiston, which was released by combustion.

We now return to your regularly scheduled thread....

jim appleyard · Jan 20, 2006

srs5694 said:
For those not up on the history of science, a brief description of phlogiston can be found here, among other places:

http://www.infoplease.com/ce6/sci/A0838824.html

Briefly: It's part of a discredited 18th-Century theory of combustion; combustible materials were said to contain plogiston, which was released by combustion.

We now return to your regularly scheduled thread....

Silly me! And I thought phlogiston was a former Soviet bloc country!

MurrayMinchin · Jan 20, 2006

jim appleyard said:
Silly me! And I thought phlogiston was a former Soviet bloc country!

Phew! And I had images of a leather clad, whip wielding woman laying down a pound of phlogiston on my a$$!

Murray

P.S. Guess I'll be paying to ship water again...

jim appleyard · Jan 20, 2006

Is it possible to make ammonium thiosulfate from scratch? Perhaps that way is can be made in small enough amounts to avoid the hygroscopic problem?

pnance · Jan 20, 2006

What the idea of making it in solution? Doesn't 60 parts, by weight, sodium thiosulphate and 40 parts ammonium chloride make ammonium thiosulphate (and some table salt, sodium chloride).

pnance · Jan 20, 2006

and some water

Tom Hoskinson · Jan 20, 2006

pnance said:
What the idea of making it in solution? Doesn't 60 parts, by weight, sodium thiosulphate and 40 parts ammonium chloride make ammonium thiosulphate (and some table salt, sodium chloride).

Yes. Take a look at the OF-1 Fixer recipe in the Apug Chemical recipes.

If you don't care for the chloride, you can use ammonium sulfate instead of ammonium chloride.

pnance · Jan 20, 2006

Is OF-1 a stock or working solution?

Photo Engineer · Jan 20, 2006

If you mix 1 mole of sodium hypo and one mole of ammonium chloride, you get one mole of a mixture of salts, but the goal of using ammonium salts, and the reason that an ammonium fix works so well is due to the fact that ALL other counter ions are removed or absent. So, if you want ammonium hypo activity, you must eliminate all sodium ions. This is what fails when you try to make ammonium hypo yourself.

It takes a sophisticated plant or operation to make pure ammonium thiosufate, and to boot it is not very stable as a dry powder.

PE

Dry Ammonium Thiosulfate

MurrayMinchin

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