I have also been experimenting with copper plating.
With moderate success. It's not too difficult to get a copper deposit on steel, the trick is keeping it on
Would love to hear what you learned, my experiences so far :
Disclaimer: my chemistry knowledge is not much these days, but I like to experiment, experts feel free to correct me here.
General safety warning for anyone trying this:
Wear old/work cloths, wear protective gloves and glasses/facial protection at all times!
WORK OUTSIDE in the open air.
Away from children animals plants humans etc.
Do not eat drink or smoke or work near fire.
Don't breath in the fumes.
If you don't know what you're doing, don't do it
I use Acetic acid (a common cleaning product)
As this is a "fairly safe" acid. But the fumes are horrible
Be careful, hydrogen might form at some stages of these processes.
And since there is also electricity involved..
spark + hydrogen = boom!
Be careful
If you put in lots of copper pieces and wait a really long time (days/weeks) the solution will turn bright blue meaning some copper has dissolved. Do not close of the jar completely as pressure might build and do NOT keep this in your house.
(Btw, congratulations you will have now created your first chemical waste. Do not dispose of this solution through a drain !
When finished add some steel wool and wait until the blue is all gone.
It will absorb the copper.)
A quicker way is to hook up a long piece of coiled up stripped copper wire (donor) to the plus of a single 1.5v cell, and another scrap piece as a temporary "dump-site" to the minus.
For safety I always add a an ampere meter in the plus line to monitor the current.
Once you have a decent copper acetic acid solution,
connect the stainless steel object to the minus site of the electrode, and a (fresh) donor coil to the plus side.
Suspend both in the solution. Copper will now deposit on the object.
If you wait an hour or so, the object will look like it's fully covered in copper ! But unfortunately, most will rub off easily..
I believe one of the problems is, that we have little control on how and where the copper deposits. I assume oxidation and corrosion during the process won't help either.
Adding a little salt might help with the conductivity, but if you add to much, chlorine (dangerous) and hydrogen(explosive) gas will develop.
Adding some fine sugar to the solution, results in smaller crystals.
Other than that, a lot of patience, retries and runs are necessary.
And I have some promising but not picture worthy results, where after polishing a thin copper shine was still left on the steel.
But other attempts seem to mainly "rust" the steel
I read somewhere that the ss from shapeways is covered with a protective coating against staining. This will interfere with the plating, as will finger-grease and such, so proper cleaning/sanding/polishing is a must
If I'm able to polish and clean the steel better prior to plating, I hope the results will improve.
Also thinking "baking" the object with the rough deposits, to see if it
might weld/stick better.
The final goal is to also use the copper base for adding silver.
Either with a more durable rub-on solution, or perhaps just dunking in molten silver. (I had some items silvered (quite a thick layer) this way, but not sure how they did it)
Maybe even use a soldering iron and the new lead-free but silver base solder used in electronics.
But I do these experiments mainly for fun