Sodium Thiosulfate clumps

darkroommike · Mar 1, 2020

I was given a 100# drum of Kodak Sodium Thiosulfate, Prismatic, it's over half full, say ≈60#, but it looks like the damp got to it. (It was stored in a basement.) I haven't dug to the bottom, I'll wait until it's nicer so I can take it outside, but the top has clumps. I was also surprised to see the pasteboard drum had neither a metal bottom or a liner.

Should i plan on drying it out completely? I could do it on my porch in darkroom trays (dusty) or in the oven (don't tell my wife!).

Any thoughts?

Anon Ymous · Mar 1, 2020

This is/was likely in pentahydrate form, so had quite a lot of water anyway, there's not much point in trying to make it anhydrous. Why not try and see how it works as it is?

Louis Nargi · Mar 1, 2020

I buy it in a 50 lb bag stored in the basement and it works fine for what I use it for. Non harding fixer.

mohmad khatab · Mar 1, 2020

Anon Ymous said:
This is/was likely in pentahydrate form, so had quite a lot of water anyway, there's not much point in trying to make it anhydrous. Why not try and see how it works as it is?

I partially agree with you.
But I am thinking about adding (ammonium chloride) at 30% - it will kind of come close to being converted to (ammonium thiosulfate).
I did this experiment and it worked very well, but it took some time to completely melt.
But the final results were very great.

mshchem · Mar 2, 2020

I would use it as is. If you want to get picky you could just adjust the specific gravity of the solution. That's an awesome find. Kodak raw chemicals were the best. That drum could be 80 years old.
When I mix my own I usually make the Kodak F6 formula, w/hardener (low odor) . Straight sodium thiosulfate penta hydrate works fine all by itself.

mshchem · Mar 2, 2020

BTW if you overheat it you will get anhydrous na thiosulfate. White powder hard to dissolve. Gently drying in a warm sunny spot would work. But it should be fine as is.

MHOFWIW, Best Regards Mike

Anon Ymous · Mar 2, 2020

mohmad khatab said:
I partially agree with you.
But I am thinking about adding (ammonium chloride) at 30% - it will kind of come close to being converted to (ammonium thiosulfate).
I did this experiment and it worked very well, but it took some time to completely melt.
But the final results were very great.

Yes, it works very well.

beemermark · Mar 3, 2020

A very long time ago I had an older friend that taught me how to work in the darkroom. He had a cardboard drum about 2 feet diameter by 3 feet tall of Sodium Thiosulfate. When it came time for the fixer he'd hit with a hammer, grab a hunk and throw it a bucket of water. Worked every time.

john_s · Mar 4, 2020

beemermark said:
A very long time ago I had an older friend that taught me how to work in the darkroom. He had a cardboard drum about 2 feet diameter by 3 feet tall of Sodium Thiosulfate. When it came time for the fixer he'd hit with a hammer, grab a hunk and throw it a bucket of water. Worked every time.

It needs some sulphite or metabisulphite to stabilize it.

mshchem · Mar 4, 2020

beemermark said:
A very long time ago I had an older friend that taught me how to work in the darkroom. He had a cardboard drum about 2 feet diameter by 3 feet tall of Sodium Thiosulfate. When it came time for the fixer he'd hit with a hammer, grab a hunk and throw it a bucket of water. Worked every time.

Nice! I remember something similar, a old fellow dumping Kodak powdered fixer in a bucket of water, no stirring, he would come back in a couple days, it would be dissolved.

darkroommike · Mar 11, 2020

mshchem said:
BTW if you overheat it you will get anhydrous na thiosulfate. White powder hard to dissolve. Gently drying in a warm sunny spot would work. But it should be fine as is.

MHOFWIW, Best Regards Mike

It's been a while, I'm no longer teaching, and am getting into woodworking, too.

mshchem · Mar 11, 2020

darkroommike said:
It's been a while, I'm no longer teaching, and am getting into woodworking, too.

Woodworking. Excellent. I have furniture my father made for me, beautiful. It's a lot like photography. I'm more of a carpenter.

darkroommike · Mar 16, 2020

mshchem said:
Woodworking. Excellent. I have furniture my father made for me, beautiful. It's a lot like photography. I'm more of a carpenter.

And if you think GAS is expensive in photography, try pricing old woodworking tools!

RalphLambrecht · Mar 16, 2020

mshchem said:
I would use it as is. If you want to get picky you could just adjust the specific gravity of the solution. That's an awesome find. Kodak raw chemicals were the best. That drum could be 80 years old.
When I mix my own I usually make the Kodak F6 formula, w/hardener (low odor) . Straight sodium thiosulfate penta hydrate works fine all by itself.

+1

Sodium Thiosulfate clumps

Privacy & Transparency

Privacy & Transparency