Question regarding mix of copper sulphate bleach

[gphoto120]

I want to make sure I have the correct order for mixing the stock bleach…I want to use for Lith redevelopment
in Tim Rudman’s toning book he stated:

1. 50g Copper sulphate mixed with 750 ml distilled water
2. Add 6.5 ml concentrated sulphuric acid
3. Add sodium chloride 50g
4. Top up to make 1000ml
Can anyone confirm the above ? Using sulphuric acid, I want to make sure of the order of mix….
Thanks,
Gary P

 

[koraks]

The order doesn't matter much; the ONLY really important thing is to add the acid to a much larger volume of water and not the other way around. It doesn't matter if there's already stuff like copper sulfate dissolved in that water.

 

[gphoto120]

The order doesn't matter much; the ONLY really important thing is to add the acid to a much larger volume of water and not the other way around. It doesn't matter if there's already stuff like copper sulfate dissolved in that water.

Thank you so much for your reply…. I was concerned primarily with the use of sulphuric acid never having any experience with it. I do mix my own developers etc. but never any recipes calling for a caustic acid.

 

[Donald Qualls]

A couple points with sulfuric acid. First, you don't really need concentrated acid. Battery acid will work fine, by using a larger volume (it's 30% strength, so you'd use 3 1/3x as much compared to concentrated) -- and it's significantly safer to handle and easier to get (I think I saw it available on Amazon; I've gotten it at auto parts stores in the past). Some of the industrial strength drain openers sold in Big Box stores are sulfuric acid, too, though they may not tell you what concentration (if they don't have any other ingredients, a hydrometer -- to read specific gravity -- will let you find that information). Some may also contain sodium silicate to protect pipes; those won't work for this purpose (but that should be on the label). They may also include dyes and such; I'd call these a last resort.

Second, even battery acid has some surprises. If you wear clothing made of (mostly) cotton while measuring and mixing sulfuric acid solutions, it's very likely you'll find small, neat holes in the clothes after the next washing. Even exposures that won't cause an itch on skin can do this. Obviously, then, you should wear well fitting safety goggles and work in a well ventilated area (ideally outdoors) when mixing this bleach.

 

[gphoto120]

Thanks for the replies…I was able to get the sulphuric acid from Carolina biological supply in small quantity 30ml 96-98%. Very good place to deal with ..fast shipping and very reasonable price along with other necessary items in case anyone else is looking for the chemicals and lab supplies.

 

[koraks]

It's all up to you, but I much rather deal with the more moderate 35% stuff you get at the auto parts store. You were concerned with this stuff so I'm kind of surprised you seem to actively seek out the most risky approach to begin with.