View Full Version : Copper sulfate solution help

loose nut
03-10-2017, 09:42 AM
i want to mix up some copper sulfate solution to plate a thin coat of copper onto steel. Do you mix it with water or is there some other chemical needed, like acid etc. Not a chemist and need help!

03-10-2017, 09:48 AM

03-10-2017, 10:35 AM
Copper sulfate is still available in many "old fashioned" hardware stores, Tractor Supply, and some agricultural chemical places. It is sold as root remover for drain systems. It will dissolve easily in distilled water (less than a buck a gallon at the big supermarket or Big Box store).

The first thing is to clean the surface to be plated very very well. When I was doing plating for some research work I would clean the surfaces with a light scour pad, soap and water, rinse with distilled water, clean with distilled acetone, and a final rinse with distilled water. If the water doesn't sheet evenly across the entire surface then your plating is doomed.

If you are just using the copper for a temporary coating then painting the copper sulfate onto the steel will work. Rinse it off afterwards because the plating involves the creation of iron sulfate, which is an acidic salt and will promote later corrosion.

If you want thicker, more durable coatings you will probably want to look into electroplating. It's very simple - you make up a bath of the copper salt, you hang the steel on a wire, hang a copper electrode on another wire, and pass current through. If you aren't being fussy you can plate your steel with copper sulfate in water using a car battery. That won't give you the best finish and best adherence, but it will give you some that may be suitable. On the other hand if you want a coating that is precisely thick, very even, and sticks tighter than an ex-wife sticks to your paychecks... you will need to use more complicated baths containing a half dozen chemicals, a fancier power supply, and a better bath set up.

If you are willing to spend a few bucks then you can buy one of the kits from Caswell. https://www.caswellplating.com/. They get you into the bottom end of plating pretty darn painlessly. Their kits contain pretty much everything you need, the instructions are well written, and their help desk is actually helpful. Or go browse YouTube - lots of videos on plating with copper.

Rich Carlstedt
03-10-2017, 11:39 AM
We used copper sulfate for marking out some steel parts.
our "formula" was able to handle steel that may not be cleaned as is normal
We used distilled water warmed to about 120 degrees
then added sulfuric acid ( battery grade) to about 10 % of volume of the water.
Then dropped in the copper sulphate crystals (root killer) and bit of table salt.
When the solution becomes saturated, the Blue Vitrol ( Copper Sulfate commercial name) stops dissolving .
Pour off the solution and use it . The left over crystals can be saved.

The salt and sulfuric acid accelerate the copper coating on contaminated surfaces.
Of course , following Dan's suggestion is great stuff


03-10-2017, 01:28 PM
Acid based copper electrolytes will self-plate (no electric connections) on steel with little or no adhesion. Better to use an alkaline base for bare steel--At least for a strike coat. Acid based can then be used over that for build-up thickness.

03-10-2017, 01:32 PM
It's sold at farm supplies, from memory a hoof hardener for sheep and horses, just add the blue crystals to hot water until it won't take any more, aka saturated solution.
Anhydrous copper sulphate is white, goes blue in the prescience of water, used as a test for water in fuels etc (applied with grease to dipstick) to make bake blue copper sulphate till your "water of crystallisation " is driven off, can be used as a desiccant for air supplies and in dessicators where silica gel can't be used, rare btw.
Beautiful coloured solution imho,

03-10-2017, 02:05 PM
... from memory a hoof hardener for sheep and horses, just add the blue crystals to hot water until it won't take any more ... Beautiful coloured solution imho

"Bluestone" solution also works as a spray against potato blight!

03-10-2017, 06:22 PM
Beautiful coloured solution imho,

The crystals that are grown from Copper Sulfate solution can be quite large and are very beautiful. An English artist, Roger Hiorns, filled an abandoned flat with over 20,000 gallons of copper sulfate solution and induced slow crystal growth on the walls, floors, and ceiling. Many of the resulting crystals are several inches across. The result is ... interesting.