Q. Has anyone any experience of electroforming ductile iron to a thickness of about 60 microns? Any ideas gratefully received!
R&D practical scientist
Chesham, Bucks, UK
A. I've seen electroplating with iron for soldering iron tips, and heard of electroforming it, Trevor. But what I've seen wasn't at all ductile and was nowhere near that thick :-)
Ted Mooney, P.E.
Pine Beach, New Jersey
Q. Can anyone provide me with a formulation for low stress stable ductile iron electroforming in thicknesses up to 0.5mm? I know it is possible from sulphate, sulphamate, chloride or fluoborate baths but I have to rule out the chloride and fluoborate baths for environmental/corrosion issues.Robert Chilton
R.A.Chilton - Chester, UK
A. I don't believe you will find one.
Falls Township, Pennsylvania
A. 19th century formula! 40 gm iron sulphate 200 gm potassium sodium tartrate 0.4 lit ammonia 25% 0.6 lit waterGoran Budija
August 24, 2010
Q. I need some pure iron in tube form. Will I succeed trying to plate onto, for instance, a wooden dowel coated with carbon dust?Paul Roberts
- United Kingdom
March 15, 2011
A. A wooden dowel wrapped in copper foil will do. Make sure you have a rag slightly oiled and rub it on the foil exterior. It will have no adhesion.Mario Tabernig
October 19, 2012
A. Hi Paul. Another approach used for complicated shapes, where you can't slide the iron electroform off of the mandrel, is to make the mandrel out of aluminum and dissolve it out with caustic soda. Good luck.
Ted Mooney, P.E.
Pine Beach, New Jersey
April 3, 2009
Q. Hi!, "iron being plated on copper" is the same experiment we are working on at school. The problem for us is that we are trying to obtain the most uniform layer of iron possible on the copper wire. Is the process of electrochemistry sufficient to deposit a uniform layer of at least 95% percent yield? or is there anything we can add to compensate for a uniform surface area?Ana-Patricia Lopez [last name deleted for privacy by Editor]
- Chula Vista, California, U.S.
A. Hi, Ana.
Plating thickness is directly proportional to current flow (see Faraday's Law). So, to get uniform distribution, the most important factor is to supply uniform current density through optimum placement of anodes and non-conductive shields. Good luck.
Ted Mooney, P.E.
Pine Beach, New Jersey
August 6, 2009
Q. Hi Guys,
Can one electroplate iron onto gold as well as it can be done on copper?
- Toronto, Ontario, Canada
April 29, 2012
A. According to "The Electroplater's Handbook" [link is to product info at Amazon] iron and gold do not bond well together. You'd want to plate a layer of copper on the gold before plating with iron.
Usually people want to plate iron with gold, not the other way around.
- Chubbuck, Idaho USA
Electroforming Iron onto a Fusible Metal MandrelDecember 19, 2015
Q. I wish to make molds to chill-cast high-purity aluminum for bright anodizing, using hot FeCl2 electrodeposition to make shell molds perhaps 3/16" - 1/4" thick. The plan is to cast the mandrels in Rotometals' 281-338F dimensionally stable alloy, polish them up, degrease and then smear with powdered graphite as a conductive anti-adhesion layer so that the mandrel will not "tin" the inside of the electroformed mold when melted out. I plan to adapt the periodic current reversal method of USP 2451341 to get uniform dendrite-free iron deposition.
1) Does anyone have experience using graphite in this way, or if not, do they think it would work?
2) If I do get a "tinned" surface on the mold, would conc. HNO3 remove the coating of bismuth-based alloy and leave unharmed passivated iron?
3) Is Fe pickup from the mold by the molten aluminum likely to introduce enough Fe at the casting surface to stop me getting a mirror-bright anodized finish? (I know this is more of a foundry question, but maybe someone has tried to bright anodize Al permanent-mold castings).
Hobbyist - Gundagai, NSW, Australia
A. Hi Colin. My understanding of what you said is that you want to make a shape out of a low melting point tin-bismuth alloy, electroform iron onto it 3/16" to 1/4" thick to create a mold made of iron, melt away the fusible metal, and cast your aluminum in the electroformed iron mold.
My initial comment is that nothing is impossible but you have at least 1000X as much confidence in old patents and electroforming of iron as I have. But good luck!
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"
January 2, 2016
A. Hi Colin
An interesting project so here are a few thoughts to help you on your way.
Iron plating is rarely used in the plating industry -- mostly we are looking for things that don't rust
Ferric chloride is not s promising basis for a plating bath. It actually reacts with iron and is a common etching agent so it will start to dissolve your plating as soon as the current is turned off.
I have plated pure iron from a simple ferrous sulphate bath tho' not the thickness you are asking. It needs a little sulphuric acid to make it work.
Patents can be a snare and a delusion. They rarely offer a working process. They are there to protect an idea only and sometimes to deliberately mislead the opposition!
Reverse plating and the like introduce a whole raft of variables (and headaches) that you could well do without.
Why Iron? Nickel is simple to plate and its natural passive surface should minimise any "soldering" problems.
I have rarely plated nickel over a mm thick but I have plated copper to several inches so possibly a thin Ni plate with a copper build up would be worth considering.
January 31, 2016
Q. Hi Geoff (and Ted)
Thank you for giving my question consideration and responding. I am a backyard tinkerer not connected with the plating industry, and my choice of iron was based on ease of obtaining it and generating the chloride salt. I wouldn't know where to start trying to get nickel salts, let alone the metal itself, and given its toxic and potentially polluting nature, I would not be surprised if it is on a restricted list in this country. Also, I suspect nickel and its salts would be expensive and one would probably have to own a plating business to get it. A spillage of ferrous chloride, by contrast, is environmentally quite benign - the worst thing it puts into the environment is chloride ion - the whole of Australia is red with iron. And, importantly for me, its cost is only that of the HCl needed to make it. I have tons of scrap iron
There is quite a bit of literature going back about a century on iron electrodeposition; it was used to make tyre moulds for instance, and may be still for all I know. It was once used for reproducing banknote printing plates by the US Treasury. I agree that ferric chloride is not a good basis for plating; most documents on the subject stress the importance of keeping iron 3+ levels in the bath low. Air for agitation is likely to oxidise the ferrous ion to ferric, so I plan to hermetically cover the bath with clingwrap and agitate using argon from my TIG welding set as blanketing gas. The gas will be recycled to the sparger at the bottom of the bath using a 3000-litre/h aquarium pump off Ebay. Net argon consumption should be small. Bath heating will be by quartz tube with a Nichrome coil inside, salvaged from a cheap radiant room heater, glanded into the bath walls with silicone. Bath lining will be PVC, heat gun welded at the seams and bonded to a support shell with air-moisture-curing polyurethane glue (bath temperature will be uncomfortably close to the glass transition temperature of PVC).
I, too, have plated iron from a sulphate solution as a tryout. I got about 1 mm before my power supply burned out (15A on about 0.5 sq.ft , i.e. 30 A/ft). The iron was brittle to the point of being crumbly I could almost crush it in my fingers, and I had incipient dendrites. A bit of annealing on a hotplate might have fixed the brittleness. I didn't think to add acid. One cannot buy sulphuric acid in this country any more, even for batteries, but a few chloride ions in the bath from HCl shouldn't matter. Chloride baths are run at higher temperature and, apparently, can produce a ductile stress-free deposit if done right.
PET (polyethylene terephthalate, Dacron) is surprisingly resistant to a wide variety of inorganic chemicals, and I plan to use it in the form of geocloth for an anode bag. The bath will be Fisher-Langbein, FeCL2.4H2O 300-450 g/l, CaCl2 150-190 g/l, 85 °C, pH 1.5, current density 2 9 A/dm2 (20 85 A/ft2). The low pH should help to minimize formation of the ferric salt. For a power supply to cover any sort of reasonable area, I will probably have to butcher a microwave oven transformer (~1200W) and do a multi-tap secondary out of copper strip, then rectify and filter. That should potentially give me up to 200A at a nominal 5V. Oh, and THICK cables.
I may try recirculating the bath through a Dacron filter, but I am not 100% sure about the aquarium/fountain pump I saw on Ebay. The vendor boasts that it is corrosion-resistant, being made of plastic and 316 stainless. It is supposed to be OK for salt water, but hot FeCl2 + HCl is a whole other salt mix. I fear, at the very least, chloride stress-corrosion cracking.
Regarding current reversal, I will have a setup such that I can go from DC in one direction to DC in the other, with mark/space ratio continuously variable between. This will be accomplished with a diode/phototransistor looking at a specially shaped piece of Al foil on a slowly turning, speed-controllable black disc. The shape is formed from two opposing Archimedes spirals and is pretty much Ace-of-Hearts shaped, with the cusp at the centre and the vertex at the edge. With the eye near the edge, there is only momentary activation of the relay; with the eye at the centre, it is continuous. It will control a 30A DPDT relay (or two) for swapping polarity. At least I can give it a go and see what happens.
So that's the plan.
- Sydney, NSW, Australia
February 4, 2016
A. Hi again Colin
I admire your aims but your taking on developing a whole new set of techniques at once. Let's see if we can try to simplify a little.
First. Aus is a major world supplier of nickel. My first strategy would be to find a local plater and persuade him to let you have a couple of litres of working nickel solution and a stub end of an anode. (this may cost a couple of tubes of the amber nectar!) You would not believe how much effort goes into converting a published formulation into a reliable working process so it would be well worth your time.
If you must use iron, a sulphate bath is much easier to source. Garden centres sell ferrous sulphate (sulphate of iron) for use in 'lawn sand' to suppress moss. You will need a little acid and, since we are experimenting anyway, I would try vinegar (5% acetic acid, use clear not coloured vinegar and steer well clear of balsamic!). It is unlikely that the chemicals would be pure enough to plate immediately so you will probably have to carbon treat and dummy the bath before you get good plating whatever the source; another reason to use a known working nickel solution.
I am impressed by your ingenious PR plating arrangement 'tho I am not convinced that it will add anything but more variables. For every plater advocating PR there are more obsessed with absolutely ripple free DC.
If you would like to try a simple approach to pulse plating just use a half wave rectifier. Don't worry that it does not produce a square wave output. People spend thousands to obtain square waves but have never put an oscilloscope on an actual plating cell which has considerable capacitance and modifies the waveform dramatically.
Good luck with the project _
August 8, 2017
A. Very very late answer
Russians are masters of iron electroforming and brush plating. Some old Russian books on iron plating and electroforming are downloadable free at
Hope it helps and good luck!
- Zagreb, Croatia
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