Electroforming solution

[SteveWright]

Does anyone have a formula for the electroforming solution. I have 5 pounds of copper sulfate in the garage and am working on my last quart of the Rio Grande solution, so I thought I would do it myself.

Steve

[Three Muses Glass]

I have a recipe that I've never tried but I got it from a great source. I've never tried it because I don't know where to get Sulfuric acid.

The Bath

For 1 gallon of distilled water-
32oz. Copper Sulfate
120 ml. Sulfuric Acid
10 ml. Brightener

For 2.5 gallons of distilled water-
5 pounds Copper Sulfate
300 ml. Sulfuric acid
25ml. Brightener

For a 20 gallon bath-
40 pounds of Copper Sulfate
2.4 liters Sulfuric acid
200 ml. Brightener

To Mix-
Mix the bath 1 or 2.5 gallons at a time. Pour a 2.5 gallon container of distilled water into a CLEAN 5 gallon bucket. Carefully measure the sulfuric acid and add it to the water. Carefully weigh the copper sulfate and add it to the mixture. Carefully measure the brightener and add it to the mixture. Using a 1" thick CLEAN pyrex rod (grind off the sharp end) stir the mixture until all of the copper sulfate has dissolved. Usully takes several minutes of stirring. Be careful not to spill. Pour the mixture into the tank until the desired amount of bath is made.

Note: When mixing NEVER put water into acid! This can result in explosions!ALWAYS put acid into water. Then mix in the copper sulfate.

Note: Additional brightener must be added according to use. This is determined by amp-hours. For every 40 amp-hours you add 10 ml. The basic formula is 1 ml. brightener for every 5 hours at 1 amp.

Note: Care should be taken not to contaminate the bath with organic substances such as sandblast grit, dirt, oils, etc.

Well, there you have it Steve. If you know where to get sulfuric acid, let me know. My solution is contaminated from using copper plumbing elbows which are NOT solid copper as i found out.
I ran across the papers yesterday while cleaning the glass magazine/class notes bookshelf. Good timing!

[SteveWright]

Thanks Rebecca. I'll try to tacks some down.

I have about 50 ml of brightener left. Do you have any idea of its composition?

Steve

[Three Muses Glass]

Hmm. No I don't, the paper didn't say either. It looks like a super concentrated e-forming solution but......shrug.

Looking online for sulfuric acid, someone recommended pool chemical stores.

[SteveWright]

I found it at Graingers:
http://tinyurl.com/3p5fc3r

It comes in various dilutions of Normal, like .1 normal or .05 normal. I need to contact a chemist friend and see what he says.

Steve

[SteveWright]

Graingers has this in 1.0 Normal:
http://tinyurl.com/3ckp5oy

Waiting to hear back from my chemist buddy.

Steve

[Three Muses Glass]

Fabulous! Let me know what he says please.

[JEK3]

You can also get sulfuric acid at auto parts stores. Just ask for battery acid.

[houptdavid]

Liquid fire drain cleaner at the hardware store

[SilverReflections]

I'm going to guess that the sulfuric acid in the recipe may be concentrated sulfuric acid, like ~18 M so if you get it a lower concentration then you'll have to make adjustments. (And 1 N = 0.5 M sulfuric acid, H2SO4) They list some concentrations here, http://en.wikipedia.org/wiki/Sulfuric_acid , not sure if they are 100% accurate. I also wonder what the concentration of 32oz CuSO4 is in the recipe? I've wanted to make some of my own also but have had difficulty tracking down a recipe that clearly states amounts and concentrations or final concentrations in the end solution so I put that project on the back burner. Would love to find a clear answer though.

Tina

[SteveWright]

He said the same as Tina, 1 Normal is half strength and referred me to:
http://tinyurl.com/3n7xxqv

Steve

[SteveWright]

My chemist friend offered more advice: Don't mess with the concentrated sulfuric acid without a fume hood.

I also misunderstood what he said about the 1 Normal version. Doubling the quantity of the 1 normal would not be the equivalent of the concentrated.

I think i will just order solution and not tease my already iffy lungs.

Steve

[SilverReflections]

Yes, you have to be very careful with the acid. I work in a lab so I have access to all I would need to do it safely expect for the proper concentrations of things lol. It is safer/easier to sometimes just buy the pre made solutions. Also, the 1N = 0.5 M, so if the recipe calls for 120 ml of concentrated sulfuric at 18M you would need 36x the volume of the 1N, or 4320 ml, to get the same final concentration in the solution which is more than 1 gallon already I believe. So that solution of sulfuric is too dilute anyway.

[RSimmons]

There is often a nitric acid component in commercially produced electroforming solutions. Brighteners usually have some level of polyethylene glycol polymer included. I've made it from scratch and while it does work I have had better results from the stuff from commercial suppliers. All of this stuff is dangerous to work with in concentrated form, especially if you don't have a good chemical fume hood on hand.

Robert