Iron Plating (electrodeposition of iron) for art, research, hobbies, & non-industrial

A. Hi Chris. I think it would be more practical to use 300-series stainless, which is essentially non-magnetic, although not 100% so. I think you will have problems with code compliance if you use copper pipe; iron-plated copper doesn't sound very safe.

If absolutely necessary iron plating of the I.D. of copper pipe can be done, although you would also have to think about whether all the copper at the joints is covered and there are no sneak paths through pipe threads or whatever. Again, robust, reliable, pore-free, iron plating of a pipe I.D. probably can be done, but it is not something easily dispatched.

Luck & Regards,

A. Iron plating is not commonly done because there are usually other, better alternatives. I say "usually" because iron plating is cumbersome and the deposit will easily rust. But iron also has its attractions (ha ha) - it is very hard and can withstand high temperatures without crazing. In any case, you definitely don't want to try iron plating in a non-industrial setting. Most plating is done out of acidic fluoborate baths or the more corrosive chloride chemistry.

Depending on the geometry of your part and the thickness of the deposit you're looking for, contracting out a job such as yours shouldn't break the bank. So don't run down to the Lotto office just yet.

"THE" brush plating book:
Electrochemical Metallizing by Marv Rubinstein

on AbeBooks

or eBay or

Amazon

(affil links)

A. Hi Robert. Yes it is possible to do iron plating. To the best of my knowledge all soldering iron tips are iron plated (that's just one layer of their plating though). A few other things are iron plated, but it's not one of the really popular processes. The subject is covered in the Metal Finishing Guidebook (any year since 1997 except 2004).

However, iron is rather difficult to plate because of the multiple oxidation states of iron which interferes with solution life, requires filtration, prevents useful air agitation, etc. Do you have prior electroplating experience that you can bring to bear on taming this tricky process? Further, it's probably not the right material for this application of building up worn parts. You probably actually need to do nickel plating for integrity of the coating.

Indispensable for your situation is Marv Rubinstein's Electrochemical Metallizing, the authoritative text on brush plating repairs. Good luck.

I was the one that asked about the iron plating ... Thanks Ted.

A. Iron plating solution (19th century):
40 gm iron sulphate
200 gm potassium-sodium tartrate ⇦this on eBay or Amazon [affil links]
0,6 lit water
0,4 lit ammonia(25%)
iron anode

Hi - I just found out about the additional reply to my letter on iron plating. Thanks to Goran Budija.

A. Try to visit (or contact via e mail) Electrochemistry institute in Zagreb. They have some very good books on electroplating subject (especially Dettner/Elzes handbook Hanbuch der galvanotechnik)! Good luck!

"Electroplating"
by F.A. Lowenheim

on AbeBooks

or eBay or

Amazon

(affil links)

A. Iron plating is more difficult for hobbyists than some other types of plating, Gamini, because iron has multiple oxidation states. Without proper attention, or with exposure to air, the iron will oxidize to the higher oxidation level from which state it is not longer soluble and can't be plated -- so avoid air agitation.

I think a hobbyist with no plating experience will have a significantly harder time successfully doing iron plating than starting with something else like nickel or zinc, so if you are determined to learn to electroplate, I'd suggest you practice with nickel plating first.

Some plating references don't even cover iron plating because it's rather uncommon, but 6 baths are discussed in Lowenheim's "Electroplating" →

The simplest is probably the
240 g/l FeSO₄.6H₂O bath operated at
pH of 2.8-3.5 and
temperature of 32-65 °C,
current density 400-1000 A/sq. m.

Good luck!

A. I have found a simple and reliable plating solution for plating hard iron onto copper soldering tips:
1 liter Ferrous (II) Chloride 0.86 Molar (11% conc),
240 grams ferrous sulfate ⇦this on eBay or Amazon [affil links] heptahydrate FeSO₄.7H₂0, and
150 grams Sodium Citrate Na₃C₆H₅0₇.

I use about one cup of solution with a malleable cast iron washer in the bottom as a spent anode. Just hang the soldering tip into to solution as the cathode at about 50-100 mA and plating time and finish will vary with temperature and current. This produces a very hard and durable iron finish at low temperatures.

---

Thanks a lot, Michael!

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Try to find plating shop that can iron plate your works. You can do it yourself too. Simple iron plating solution:
iron sulphate 180-250 gm
iron chloride 42 gm
ammonium chloride 20 gm
water 1 lit,45 C temp.,1-8 a/dm2
iron anodes, pH 4,5-6

A. It would be prohibitively expensive to set this up yourself for a non-proven market, but there are plating shops who could do iron plating onto the stainless knives for you. It will take some shopping since iron plating is an uncommon process and plating onto stainless is a somewhat uncommon process.

But are you sure you can't find a 'rust paint' that will serve your needs? It would be much cheaper and easier. Good luck!

A. Hi Douglas. There is a chapter on iron plating in the Metal Finishing Guidebook. But I'm personally not aware of electroforming of iron to structural integrity, and tend to doubt its suitability. Copper or nickel seem more promising if they would meet your needs. Good luck.

A. Have your library get a copy for you to check out of "Modern Electroplating" [on AbeBooks, eBay, or Amazon affil links] edited by Lowenheim. Mandich may have edited the latest version. At 90 °C, there is not much that will work for a tank.
A well reinforced tank of CPVC may work. If you are a lab project, heavy wall pyrex beakers [beakers on eBay or Amazon [affil links] may work. Watch out on hotplate heaters as the whole beaker may jump as much as two inches once in a while.
Power is DC at about 20 amps per square foot. Anode to cathode distance is normally 4 inches or so.
The book has a LOT of good information on this process. Fe III causes problems.

A. Hi John. This sounds doubtful. You have two problems to start with that demand some experience. First, you can't plate directly onto aluminum, but must zincate it first. Second, unlike the situation with some other metals, it can be hard to keep the iron dissolved at the right oxidation state (ferrous), as it will want to oxidize to the ferric state, from which it can't be plated.

I'm not saying it can't be done; but if you haven't done plating before, you might want to try some easier stuff first :-)

It might help if you told us why you need to plate with iron rather than something easier like nickel, and how thick the iron plating needs to be, and what you plan to do to keep the iron plating from quickly rusting.

Luck and Regards,

Practical Electroplating Handbook
by N.V. Parthasaradhy

on AbeBooks

or eBay or

Amazon

(affil links)

A. Hi John. That 1899 patent covers a method to activate aluminum for electroplating, and is not where I would have started in attempting electrodeposition of iron. Further, the hydrofluoric acid it employs is probably the most dangerous material used in a plating shop. Or maybe you just gave us the wrong patent number.

Anyway, I'd suggest trying a plating text first. Lowenheim's "Electroplating" ⇦[this on eBay , Amazon, AbeBooks affil links] lists 6 iron plating baths. Parthasaradhy's "Practical Electroplating Handbook" offers a number of formulations.
Lowenheim's "Modern Electroplating" [on AbeBooks, eBay, or Amazon affil links] has a pretty broad chapter on it and might be your best choice. Good luck.

Regards,

A. I would guess that John Wilkinson means patent US7235165 B2, the reagents he describes are the same as those in the above.

https://www.google.com/patents/US7235165

  Thanks for unearthing that information, Jon. What is the thrust of that patent though, if you are familiar with it? I've read its claims and don't understand what it is claiming as patentable, or even unusual. Instructions to 3rd-grade schoolchildren about how to electroplate zinc or copper with kitchen ingredients like vinegar ⇦in bulk on eBay or Amazon [affil links] and salt also start with no zinc or copper in the solution -- so it can't just be that he is starting with no metal ions in solution :-)

Regards,

A. Iron plates quite well from a simple ferrous sulphate solution.

Your proposed solution appears to contain no source of iron !
You should also know that oxalic acid is highly toxic.

A. Hi Shelley. No toxicity.

You may want to see our FAQ on Faraday's Law because it explains this a little slower and more carefully, and with graphics, but ...
When you do electroplating or electroforming, electrons are pulled away from the positive pole (anode) and are pumped through the power supply and copper wiring to the cathode. The desirable result of this is changing the neutrally charged metallic copper atoms of the anode into positively charged copper ions which will dissolve into solution and by attracted to the negative pole (cathode); while at the cathode those electrons re-merge with the copper ions to become once again copper metal.

But what the electricity also does is separate some amount of the water, H20, into hydrogen gas which evolves at the cathode and oxygen which evolves at the anode. These are not toxic whatsoever but can produce a champagne or ginger ale effect entraining some of the solution into the air. That entrainment can be an issue when there are toxic materials in the solution, for example chromic acid when doing chrome plating. But when your solution is vinegar the worst that could happen is entrainment of some resultant vinegar.

By the way, although there will always be some bubbling, there should not be a lot. That is an indication that the plating solution can't keep up because you are using too much current.

Luck & Regards,