Nasty Chemicals are Great (used responsibly )

mshchem · Aug 31, 2019

Kodak Developer system cleaner. Chromic acid (sulphuric acid and potassium dichromate) I had bad developer stains in a Jobo bottle . Tried scrubbing, no results.
I have a old bottle of the Kodak product, I poured about 15ml into my stained bottle added about 30ml water. Gave it a good shake, completely clean. 15 second job.
I saved the solution, I bet I can make that last for quite a while.
Dangerous as hell, toxic as hell, but it really works. Now I will need to take care of this as the waste will need to be taken to the city for disposal.

Kino · Aug 31, 2019

Hope you're storing it in a glass bottle.

Great stuff if used responsibly. We used to use it on motion picture processors with great results once a year. Had a Hazmat truck come out and pump out the machines after circulating it through the machines for an hour and you never saw stainless steel shine like that, even when new!

Clayton makes a "systems cleaner" we now use, but it is no where near as effective...

mshchem · Aug 31, 2019

Kino said:
Hope you're storing it in a glass bottle.

Great stuff if used responsibly. We used to use it on motion picture processors with great results once a year. Had a Hazmat truck come out and pump out the machines after circulating it through the machines for an hour and you never saw stainless steel shine like that, even when new!

Clayton makes a "systems cleaner" we now use, but it is no where near as effective...

Kodak supplied it in a square 1 liter plastic bottle. I have the diluted material in a nice heavy duty Nalgene bottle. I remember this stuff from a analytical lab I worked in about 35 years back. I never had cause to use it.
Surprised me how potent the stuff is. I'm not sure if this stuff could be sold today. I'm being very careful.
Your point is well taken, I should make sure its not going to leak. What a nightmare that would be.

AgX · Sep 1, 2019

A hint at terminology:

Between English and German I found other chemicals under allegedly equivalent terms.

guangong · Sep 1, 2019

We were taught how to use and handle nasty chemicals in high school chemistry lab in early 1950s. My hs class probably more than the equivalent of a college course today. My high school teacher was from that generation where few went to college and taught on the premise that that was all the chemistry we would ever be exposed to.
In late ‘40s and early ‘50s , as a little kid I was able to easily buy chemicals at the counter of a chemical supply house that now require all kinds of paper work. Probably the result of “slip and fall” lawyers.
Another source for some chemicals were the local pharmacy. Back then the druggists still made things.

mshchem · Sep 1, 2019

I have a friend, while we were in high school, he would order potassium perchlorate and powdered aluminum, mail order. He made some serious firecrackers. He used cardboard tubes upto 3 inches in diameter. He was able to fell a small tree with one charge.
He was careful but it's amazing he didn't kill himself.
I had a little lab in our basement, bunsen burner etc. I was the only kid with metallic Sodium .
Never was hurt amazing!

Grim Tuesday · Sep 1, 2019

Hexavalent chromium compounds like this are so toxic (carcinogenic) that they are not worth using. If I were you I'd take that whole nalgene to the city for disposal.

If you need something this incredibly corrosive to get the stain out of your bottle it is unlikely the stain could ever affect anything.

iakustov · Sep 2, 2019

Can you name more healthy "anti-stain" alternatives? My trays have stains (mostly from Amidol), I heard that 10% citric acid could do

AgX · Sep 2, 2019

Grim Tuesday said:
If you need something this incredibly corrosive to get the stain out of your bottle it is unlikely the stain could ever affect anything.

Good argument

bernard_L · Sep 2, 2019

Hexavalent chromium can (and should) be turned into relatively harmless trivalent, e.g. by reacting with the proper (don't have the numbers at hand, easy to re-compute) amount of sodium sulfite (oxidized into sulfate)
Dichromate bleach is in my experience the most effective for negative intensification. Saved three rolls of "keepers" following faulty recommended dev time, that had resulted in C.I. 0.45.
I have found that stains/deposits inside glass bottles, that resisted to several potent acids and alkalis (did not try sulfochromic mixture) were easily cleaned by half-filling with warm water + sand and shaking vigorously for a minute or so. Zero pollution. Granted, not applicable to a processing machine.

Rudeofus · Sep 2, 2019

I wonder, whether Potassium Permanganate plus Sulfuric Acid would be

as effective as
less toxic/carcinogenic than

the Kodak cleaner product.

GLS · Sep 2, 2019

Rudeofus said:
I wonder, whether Potassium Permanganate plus Sulfuric Acid would be

as effective as

less toxic/carcinogenic than

the Kodak cleaner product.

Looking at the data sheet for this Kodak product, it looks like that is indeed what it contains (and not chromium VI species), unless the formulation changed.

Permanganate is a much safer alternative to chromium VI salts, and will only be marginally less effective.

There are even stronger cleaning mixtures than chromic acid, such as a mixture of hydrogen peroxide and neat sulfuric acid; there is a reason this is referred to as "piranha" solution. However it is extremely dangerous due to potentially forming explosive mixtures, and therefore even trained chemists hesitate to use it without good reason.

AgX · Sep 2, 2019

The next step then would be combining Potassium Permanganate and Hydrogen Peroxide... I guess the cleaning effect would be thermal only...-

mshchem · Sep 2, 2019

It's Cr (VI) nasty stuff. I've worked in labs for over 40 years, I am very careful. The way Chromium compounds were used in industry in the past is scary. I remember when chrome pre-treatments were phased out in the coating industry. It was a difficult transition.
When I'm done with my darkroom, I will need to pay to get rid of the stuff. I'm not stupid, no cyanide, mercury etc.
I develop with XTOL, take my used fixer to a minilab.

Vaughn · Sep 2, 2019

bernard_L said:
Hexavalent chromium can (and should) be turned into relatively harmless trivalent, e.g. by reacting with the proper (don't have the numbers at hand, easy to re-compute) amount of sodium sulfite (oxidized into sulfate)

...

I have seen weak dichromate solutions treated with ascorbic acid go from yellow to clear and colorless. Would this be a similar reaction (going to trivalent form) as with the sodium sulfite?

mshchem · Sep 2, 2019

GLS said:
Looking at the data sheet for this Kodak product, it looks like that is indeed what it contains (and not chromium VI species), unless the formulation changed.

Permanganate is a much safer alternative to chromium VI salts, and will only be marginally less effective.

There are even stronger cleaning mixtures than chromic acid, such as a mixture of hydrogen peroxide and neat sulfuric acid; there is a reason this is referred to as "piranha" solution. However it is extremely dangerous due to potentially forming explosive mixtures, and therefore even trained chemists hesitate to use it without good reason.

This is a probably 20 year old NOS bottle. It's the old will dissolve an entire human body stuff.
Peroxides are something I would not play with. I remember when you could buy 37% (I think ) hydrogen peroxide.

NedL · Sep 2, 2019

When I open a new bottle of HC-110, I put it into 4 120ml amber glass bottles filled to the brim for storage. Today I needed to do it, found 3 bottles that previously had HC-110 in them, but the only other one I could find had been used for fixer and had silver plated out and maybe other crud plastered to the inside. I didn't try to clean it, just ordered some more from B&S... made me think of this thread, but I'd probably be too scared to use or store chromic acid anyway

mshchem · Sep 2, 2019

NedL said:
When I open a new bottle of HC-110, I put it into 4 120ml amber glass bottles filled to the brim for storage. Today I needed to do it, found 3 bottles that previously had HC-110 in them, but the only other one I could find had been used for fixer and had silver plated out and maybe other crud plastered to the inside. I didn't try to clean it, just ordered some more from B&S... made me think of this thread, but I'd probably be too scared to use or store chromic acid anyway

Wise choice.

timmct · Sep 2, 2019

I love threads like this.

I grew up in Toronto in the early 1960's...I used to walk to school with a rifle (in a case) as I was in the Cadet Corps Riflery Battalion. Try doing that today?!?

I was on rifle ranges with 30-06's and 7 X 57mm when I was 12 years old.

I went through the sulfur, potassium nitrate charcoal bomb phase, through the sugar/potassium nitrate and aluminum filings (wrapped in Silly Putty to simulate "plastic' explosives) and, yes, the metallic sodium with an ice cube to delay the reaction in a bomb form. It seems funny to say it but the favoured canister for almost every device was the screw top Kodak film cannister, pierced for a wick (from a firecracker). What fun! Only one, unlucky, one had a scorched cornea that, thankfully, healed within a couple of months.

When I worked for Sprint Systems of Photography they had a line of Direct Positive chemistry...so, no stranger to the chemistry that the OP is referring to. No wonder that line was discontinued.

Sometimes, when I was the "technical director" at Sprint, I would get asked..."How dangerous IS your chemistry?" I would always ask if the person I was talking to handled their own gasoline? "Do you, routinely, fill your own tank with gasoline?" Well, gasoline is infinitely more dangerous than any chemistry we provide; either in concentrate or working solution.

Of course I would never ask that same person if they, routinely, drive at 70 miles an hour a scant 20 inches away from another 2000 lb. vehicle, traveling at the same speed, fully loaded with 20 gallons of gasoline and with a 40 lb. lead/sulphuric acid battery up front; in the crash zone. Let's not even try to nail down how many cubic feet of oxygen it takes to burn a gallon of gas in an average car. DON'T go there!

We are lucky enough to take for granted the chemistry we rely on...at the same time we view, askance, marginal chemistry as perhaps "more" dangerous than we should.

Having said all this...heavy metals in use or in an effluent stream MUST be viewed as extremely threatening, highly toxic...assiduously avoided if at all possible.

BUT...if I have done my reading well and understood it correctly...the sun is constantly bombarding us with RADIATION!! OH NO!!

bernard_L · Sep 3, 2019

Vaughn said:
I have seen weak dichromate solutions treated with ascorbic acid go from yellow to clear and colorless. Would this be a similar reaction (going to trivalent form) as with the sodium sulfite?

Most likely, since ascorbic acid is (a) used in some developer formulations, hence is a reducer; (b) is touted as an "anti-oxidant" among "health supplements".
IIRC, trivalent chromium ions look green, at least when I perform redox exchange with sulfite.

cramej · Sep 3, 2019

I haven't used any of the few ounces I have left in a bottle, but it's neat as a historic product - Kodak carbon tet film cleaner. Safe to say that I won't be trying to put out any fires with it.

AgX · Sep 3, 2019

There still are sources of TET even at home. Likely I produced just yesterday some unknowingly when mixing a chlorine compound.

mshchem · Sep 3, 2019

cramej said:
I haven't used any of the few ounces I have left in a bottle, but it's neat as a historic product - Kodak carbon tet film cleaner. Safe to say that I won't be trying to put out any fires with it.

I've got a couple of Kodak movie film cleaner with a CFC. I fixed a gummed up Copal shutter and a Hasselblad back with about 2 mL of that stuff it's like gold.
I paid 10 bucks for a Fujinon SWD 65mm 5.6 lens and 10 bucks for a mint older A12 back. Both were fixed with this miracle solvent. Destroys the ozone layer and has enormous global warming potential.

GLS · Sep 3, 2019

DCM, DCE or chloroform would do just as good a job at de-greasing things, but are not ozone depleters. They can mar many common plastics however, so should not be used near those.

AgX · Sep 3, 2019

DCM is banned in Germany both for private and commercial use.

Chloroform will put you asleep in your workshop. But when you wake up the ungumming work is miraculously done...

Nasty Chemicals are Great (used responsibly )

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