I'd like to learn how to do electrolytic nickel and gold plating on
copper sheets. Any web resources/links etc. ? I tried to search on
google but almost all results were commercial companies.
My exact application is to
1. edm wire cut copper foil (100 microns) - about 10mm x 10mm piece
2. clean off the corrosion on the edges due to wire cut process
3. nickel plate and make total thickness 130 microns
4. gold plate about 2 microns.
(I'm not sure whether I need to do step 2).
You do, but it's just part of the process and nothing special. You'll
probably have to polish and you definitely have to clean the copper before
nickel plating anyway.
Nickel plating is not too difficult, but good gold plating requires using
cyanide - could you send off for the gold plating? Unless you are doing a
lot, it will be easier. Much easier.
Mind, the gold plating shop will usually also do better polishing and nickel
plating than you can, as they have the experience and the large volume tanks
(volume makes a difference, maybe it shouldn't but it definitely does).
No, I need to know more about what you want to do. First impression, for a
gold plated copper foil square, get it done rather than do it yourself. You
can probably buy gold plated copper foil anyway. But I expect it's a bit
more complex than that ...
What is the final finish required? Rough, dull, matt, satin, bright, mirror?
'Cos that's where you decide where to start. Ooops, I forgot the very first
question, how many?
I can do (and have done) nickel, NiCo, NiCu, NiFe, NiCoFe*, NiCrCoFe*,
copper, copper/tin and copper/nickel electroforming, and all those  plus
iron , tin and some  silver plating, but not gold - this may be partly
because it's almost impossible to get cyanide here in the UK. However if I
really wanted to I probably could get cyanide, so it may also be partly
because I simply don't want to work with cyanide, and I'm just using the
difficulty as an excuse ... I don't know how hard it is to get cyanide in
the US (where I presume you are located).
* proprietary to me. Don't ask unless you have overflowing pockets.
 depending on substrate. Eg acid copper doesn't work well on ferrous for
example, and I don't do cyanide copper, the usual alternative - but I can
plate copper on _some_ ferrous metals without using cyanide. It's tricky.
 for soldering iron tips/bits. Prevents the copper bit dissolving in the
 again depends on substrate, though I can do silver on most substrates
(and I am hopefully adding direct silver on stainless to the list next week,
fingers crossed xxxxxx)
though you can silver plate over nickel, and you can use a strike coat of
nickel over stainless - iirc it's just nickel suplhate and sulphuric acid, a
bit more dilute than eg Watts nickel with a bit more current and a bit
hotter -let me look it up.
here we go -
clean, etch in 30% room temperature sulphuric acid for 3 minutes at 3
A/Dm^2 for 2-3 minutes anodic followed by 6 minutes cathodic. It is
advisable to use two tanks, one for the anodic and one for the cathodic
cleaning, to prevent Cr and Fe buildup.
250 g/l nickel sulphate
commercial sulphuric acid 25 ml/l
- weight equivalent 50 g/l
16-22 A/dm^2, 30-40 C, for 5-10 minutes. sg 1.160. One nickel anode,
remaining anodes chemical lead.
It that the kind of advice you are looking for?
BTW, a lot of hands-on how-to-do-it plating know-how is (or was) considered
semi-secret, a kind of trade secret, like you only pass it on to an
apprentice, and it's hard to find - old craft plating workers you can get to
treat you as an apprentice are best, and old books are second best. There is
a small body of scientific literature, but that secrecy makes it not too
useful. Apparently the Russians didn't have that mentality, and their
literature has lots of stuff - unfortunately, I can't speak Russian!
At least that's my impression.
My volume is 2000 Nos. of 100 micron (10mm x 10mm) square article per
I tried to get it done locally (Ahmedabad, India), but somehow I could
not get professional quality plating here. The article is so delicate
(100 micron) that the plating people would bend/deform it due to bad
This article is used as a leaf-spring with a mild spring action (nickel
induced) to make a weak electrical contact with a moving gold plated
Whatever finish is good for a good electrical contact. Or maybe finish
is not too important ? I've never thought of the finish part. Qty=2000
maybe If I can do nickel myself, then the piece would become hard
enough, so that I can get gold done in a shop. That way even if they
slightly mis-handle the article, it won't get damaged easily.
Can you please explain this in detail. I cant understand most terms
like "anodic cleaning" etc.. I'm more of an electronics guy than a
chemical guy. But I guess it shouldn't be too hard to home plate
Sure, but in English. (Just kidding). Can you explain it in simple
steps without figures. Like: "Take a beaker and mix nickel sulphate and
whatever..". I'll find out what the above figures mean from a chemistry
Thanks a lot
Convince me it has to be made from copper. Convince me it has to be made by
edm rather than eg pressing. Then convince me it can't be made by edm of
Why not use eg beryllium copper? That's springy. Though I expect spring
steel is the actual appropriate material.
What you are asking will almost certainly cost more than a properly designed
part - at least ten to a hundred times more - if you do it that way.
Have you thought about eg the cost of fixing the parts in a frame so they
can be nickel plated? That costs, a whole lot, each part has to have a good
electrical contact too, and your local platers will either charge a whole
lot extra for the care involved to do it properly, or they will bend the
The alternative is barrel plating, where the pieces are put in a revolving
rubber lined barrel and make electrical contact by touching each other from
time to time while the barrel revolves, and touching either an electrode
with a rubber stem or the outside of the barrel, depending on process.
That's cheap, less than a hundredth of the price, closer to a thousandth or
even a ten-thousandth for something your size - but your soft copper pieces
will get damaged - but spring steel ones won't.
There may be considerations that I am unaware of, as I do not know all the
details of the part and it's intended use, but my simple advice is:
- what you are asking for can be done, and yes I can tell you how to do it,
but it would be expensive. Very expensive. Horrendously expensive,
outrageously expensive, no-one would even consider doing it that way if they
had an alternative
- can you change your requirements a bit? Why does it have to be copper?
Near the copper spring are magnets (for some other purpose) which would
impede the motion of the spring if it were made of spring-steel. (I've
checked). I don't know breyllium copper.
Edm because I do not want to invest in a pressing die. This die would
be expensive since the leaf spring has a peculiar shape with 0.3 mm
serrations. Once I'm through selling about few thousand devices, I'll
go for a pressing die.
My employees tie them with a thin copper wire (0.2 mm) very carefully,
but still those local platers don't handle them with care. And I don't
really confide in them because maybe once or twice they might do it
with care but I can't really expect them to give me a consistently good
Again, labour is cheap in India, ($10/day for a worker) so tie-ing the
pieces is cheaper.
Cu foils are omnipresent. The device works great and is proven. Only
that I need consistentcy in plating.
In my humble opinion the best way to make and plate this part, would be to
photo etch the parts out on a +8" x +10" sheet of phos. or beryllium bronze
leaving the parts attached at the corners so that the whole sheet can be
plated as one and the individual parts can be snapped off as needed. No
expensive tooling just a photo neg. of multive parts, no time consuming
EDMing and the parts are all connected electrically for easy cleaning and
Don't let the facts interfere with your prejudices
Sounds like a good idea. But I've never had any experience with
etching. For now EDM is cheap in India. And I've had good luck making
the parts. What remains is plating consistency.
Btw, I'd like to try this in future. Any leads / hints / pointers on
Would it spoil the end product if you had the sheets of foil plated before
EDMing the parts? It may then be possible to mount the sheets in frames that
would be more robust. It may also cost less!
Plating nickel over copper foil causes the output to become hard. I
have a bending process after EDM. If bending is done over plated part,
Sequence is: EDM > Bend > Ni Plate > Gold Plate