# Home-brew electroplating



## Shdwdrgn (Dec 23, 2014)

I have a pretty old narrow-gauge loco kit I'm working on, but one of the things that is bugging me is the brass wheels. Has anyone ever done their own nickle plating, and if so how did it hold up?

http://www.instructables.com/id/High-Quality-and-safe-Nickel-Plating/

I read through this article, and the process seems pretty straightforward. Some things I took away from it include making sure your source of nickle is pure, and during the plating process a lower voltage will provide a stronger bond.

Another interesting thing from this article was his experiments with tin, which seems to leave a dull greyish surface -- could be an interesting technique for weathering? However I think nickle is the correct material that I would want to use for the brass drivers. Any thoughts or suggestions?


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## J.C. (Dec 24, 2016)

don't know how well his plating will last but Micro Mart has a home kit for small parts .its been years since I've messed with plating the biggest thing is cleanliness , and I would think that you would need to remove the old plating or in your case etch the wheels slightly before plating/replating, biggest thing I did was a couple of old zippo lighters so I had to strip old plating down to steel then copper plate before the nickel used the lighters till quit smoking about 12 years later. and I belive boric acid was used , but you can buy just plating solution.


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## Shdwdrgn (Dec 23, 2014)

Considering this kit is from the 1970's, I'm pretty sure the wheels are solid brass rims on a plastic hub. I just need to be careful with placement of my negative lead so I don't get any plating on the steel axles.

Basically the above link uses distilled vinegar and a pinch of salt, and you let the nickle rods dissolve with 12VDC for a couple hours. Once you have that, you switch over to about 1.5VDC, keep the positive lead on a nickle rod, and connect the negative lead to the piece you want to plate. I think at this point it only takes a few minutes to plate the piece, and you want to move the clip around a couple times so the entire surface gets coated.


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## J.C. (Dec 24, 2016)

with having plastic centers if I wanted to color them I would go to a sporting goods store and buy a bottle of cold gun blue will give the drivers a nice blue/black color. make Shure to get a cold finish for brass not steel.


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## Lehigh74 (Sep 25, 2015)

I would have never though that you could do nickel plating at home, but the article made it look easy.

I used to work at the Philly Shipyard and for about eight months I was in Environmental Engineering. The first thing the state and federal regulators wanted to see was usually the plating shop. I found it interesting that someone asked how you dispose of the nickel acetate and there is no reply.


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## Shdwdrgn (Dec 23, 2014)

Finally got around to giving this a try... I found some NI99 welding rods, which are supposed to be 99% pure nickel. Seemed like one of the easiest sources and an $11 pack of rod would probably be a lifetime supply (unless I start going really crazy with plating parts  ). Anyway, I have a pint jar filled with white vinegar and a pinch of salt, getting good bubbles coming off the negative rod, so now I just have to wait a couple hours to see if the vinegar turns the proper color (wrong color indicates too much impurity in the nickel content). I'm using a motorcycle battery charger for my 12V source, and it sounds like I can just use a AA battery for the actual plating process. Here's hoping to success!

[Update] Three hours in, it's going slower than expect. I sprinkled in a little more salt (which about double the amount of bubbles) but I'd rather have patience than add too much. However the color is coming out almost exactly the same as shown in the article above, which means there should be no unexpected contaminants in the nickel rod.

I should also point out that the store also had a NI55 rod, but the description was that it is a nickel rod with a steel core, and would seem to indicate it is only 55% nickel. I know the NI99 rods I got are supposed to still have a very fine amount of steel in them, but it doesn't seem to be affecting the process. The real test will be when I start plating some pieces. I'm going to let this go for another 2-3 hours to make sure there is a lot of dissolved nickel, then try plating a couple pennies before moving on to brass.


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## Shdwdrgn (Dec 23, 2014)

Well, it was somewhat successful, albeit MUCH slower than indicated from the article. I ended up letting the initial mixture simmer for about 6 hours, but the vinegar now has a very strong green color to it, and is nice and clear. As with the article, I also tested with pennies. The first one I just dunked directly in the solution without any prep, and it was obvious. After about 15 minutes of plating with a pair of rechargeable batteries I washed it in the sink, and a lot of the nickel rubbed off under my fingers.

The second penny was washed with soap and scrubbed with a toothbrush before starting. Despite this the plating across the center of each face is still very thin and slightly rubbed off, although it took a lot more effort and this time it's more like rubbing through a thin layer rather than having the nickel flaking off in pieces. In the photo below, you can see a hint of copper around the neck line. Also it took much longer to get a good coating. After about half an hour I stopped and recharged the batteries, then let it go for another half hour. The picture doesn't show the details well, but there's actually a very good coating of nickel around the edge of the coin. During the process, I moved the clip about every 5-10 minutes.










My thoughts on this are that the faces didn't get well coated because they were always vertical. A lot of bubbles form on the coin during the process, and I kept tapping the clip to knock the bubbles free, but that didn't seem to do much. Also the nickel did not come out nice and shiny, however this could be beneficial for the intended pieces. It actually looks more like a dull steel color, and with a splash of dirt or rust colored paint I think it will make for a nice weathered look.

I'll practice with some brass today, and if it comes out well then I'll try it on the main rods I made last week. Since brass already has a brighter color, I'm betting it won't be as obvious in the spots where the plating is thin.

[Update] Just did a brass rod for a few minutes while eating some breakfast. No major prep, I just buffed it up with some 600-grit sandpaper, but there's a huge difference in the results! The most obvious is that the nickle is bright and shiny this time, but it is also sticking a lot better, and the plating happened much faster. The plating doesn't rub off, nor can I scrape it with a fingernail. It is still thin enough that a light buffing with the sandpaper allowed a little brass to show through, but the nickel is definitely stuck well. I also bent the rod to see if there would be a difference between angles, but this time ALL surfaces were equally covered with nickel regardless of angle. Overall I left it in the solution for about 5 minutes.

The only conclusion I can draw is that there is a problem with plating pennies. Maybe zinc doesn't bond to the nickel as well, or maybe I should have used something different to clean it with. Since brass is what I plan to work with anyway, I'm not too concerned about what happened with the pennies though.


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## Shdwdrgn (Dec 23, 2014)

I've been working on getting a good plating on some brass connecting rods I made, and having poor, grainy results. Now I know that stock brass can take a very nice shiny and hard plating from this setup as seen in the test rod I previously did. After several tries of re-sanding the connecting rods and re-plating with the same grainy results, I did some more reading.

One suggestion I read was that temperature played a part, and the mixture should be warm (such as it was immediately after it was created). Today I tried warming it a bit in the oven before plating a piece... the results were a bit better with more solid areas, but still some pitting.

The other suggestion (oddly not mentioned much) is the amperage. Even though plating is done with a low voltage, apparently you need a bit of amperage to make it work? Sounds fair. I had been doing my process with some half-charged AAA batteries, so I switched for a pair of freshly-charged AA batteries -- same voltage, but more amps. And yes, that made a big difference! The result is a thicker and harder layer of nickel. I am running it for a few minutes, then drying off the part and giving it a light buff before doing another coat. Although it still isn't coming out quite as expected, at least now it has a metallic finish rather than looking like poorly-painted brass. Maybe for a final coat I'll try to buff it up smooth and then just do a fast plating of 30 seconds or so.


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## Fire21 (Mar 9, 2014)

Although I'm not interested in doing any plating myself, it is interesting to follow your experimentation and progress. Thanks for the reports and photos...keep em coming!


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## Shdwdrgn (Dec 23, 2014)

Thanks! Apparently copper plating is a very similar process, and there are several metals that require a copper plating first before you can add the nickel plating. Guess it all depends on what results you are after.

The tender and front idler wheels on this model are also brass, so at the moment I am plating the insulated wheel on one set. It seems that frequent agitation is giving better results, but it is still a slow process. Been working it for about 30 minutes so far, but I'll snap a picture to show the results here in a bit...

[UPDATE] I think I only did another 5-10 minutes after the last post before deciding it looked 'done enough'. A quick wash in the sink followed by rubbing it with steel wool, and I think it turned out pretty nicely. Unfortunately I'm still fighting with the amount of light in my pictures (despite having three 50W bulbs pointed at the area from three directions), so I apologize for the quality...



















Now the problem is figuring out how to do the other wheel. This one was insulated from the axle, the other side is not... but I don't want to plate the axle, just the wheel.

The plating seems solid enough. I ran it between my fingers across some track, pushing into the flange as it rolled, and there's no indication on the wheel that I did anything. Hopefully the plating will be hard enough to last the life of the loco. In the end, the wheels will be getting a dirty wash for weathering so it will cover any imperfections on the sides, but I want the surface of the wheels, where they contact the rail, to be a shiny silver like polished iron.


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## wvgca (Jan 21, 2013)

a long time ago I used to do cosmetic plating on firearms, small parts mostly ..as far as I remember the voltage was 2-4, and amperage was around 5A ..and yes, a hot solution is pretty much a requirement ..
I think I still have some commercial plating solutions, brass, nickel, gold ..and hard chrome


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## Shdwdrgn (Dec 23, 2014)

How hot do you suggest? And do you happen to know *why* the temperature has an effect? My experiments this morning had the solution very warm, but not so hot I couldn't still carry the jar downstairs.


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## wvgca (Jan 21, 2013)

Shdwdrgn said:


> How hot do you suggest? And do you happen to know *why* the temperature has an effect? My experiments this morning had the solution very warm, but not so hot I couldn't still carry the jar downstairs.


about the same as hot coffee, something to do with ion activity / transfer ...

I used to plate in steps, brass, then nickel, then either gold or hard chrome , with some polishing in between .and then again at final , with about 3lb blocks of different media, like rouge and tripoli

From what I remember, low current levels made the plating not adhere as well, and would wear off easier ..

Pins, hammers and some triggers got gold, sear was polished and then hard chrome, very smooth, bolts were sometimes machine polished [swirls], think I still have my home made jig for that in the garage.. 

I looked at my bottles, and they came from Concordia Chemical in Ontario, but no current web search results ..

Areas that I didn't want plated, I brushed on hot wax ..


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## wvgca (Jan 21, 2013)

Just remembered a couple of other things..
If you are using vinegar to make your initial solution, pickling vinegar is stronger, and works quicker, and adding about 1/4 to 1/3 hydrogen peroxide will give a more even deposit


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## Shdwdrgn (Dec 23, 2014)

Yeah it's just off-the-shelf white vinegar with a pinch of salt that I'm using. Would it make any difference to add peroxide to an existing solution, or does the peroxide need to be present when you originally leach the metal in to the solution?


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## wvgca (Jan 21, 2013)

Shdwdrgn said:


> Yeah it's just off-the-shelf white vinegar with a pinch of salt that I'm using. Would it make any difference to add peroxide to an existing solution, or does the peroxide need to be present when you originally leach the metal in to the solution?


I don't remember making my own solutions...
I just added some peroxide for plating


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## Fire21 (Mar 9, 2014)

Looks like a pretty nice result on the wheel. I don't think your lighting is too bad, details show quite well.

I was wondering if you have an old DC transformer that you could use for power source. You could hook in a volt meter so you could control voltage. I'm not sure what that'd do for amperage though.


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## Shdwdrgn (Dec 23, 2014)

If I remember right, using a resistor to limit the voltage also limits the current. And the power packs I've seen at these low of voltages are usually in the mA range of output. Hmm... I DO have an adjustable supply that will output up to 3A, but it requires a source of less than 24VDC. But I could use the battery charger I used from the first step in making the plating solution (which I think puts out 2.5A) and feed that into it. Might be worth a shot...


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## Shdwdrgn (Dec 23, 2014)

I don't have any wax available to easily work with, so I thought I'd give it a try with a simple coat of acrylic paint. After being allowed to dry for a day, acrylic is a lot more resistant, but not impervious to vinegar.

I just finished up the other wheel, and overall it worked pretty good. Soaking in the vinegar definitely loosened the paint, but it still provided enough resistance to prevent the nickel from getting on the axle. I'm thinking pretty much anything might work for this purpose, even a coat of light grease. There was one place in the center of the axle where the nickel did break through the paint, but the plating was so rough that I easily knocked it off with the steel wool. Cleanup was also a breeze with the acrylic. Since it was practically falling off anyway after the vinegar bath, it came right off in the sink with a light wipe of a toothbrush.

As with the other side, I once again had trouble getting more than a very thin layer of nickel on the outer face of the wheel. The inside of both wheels plated up similar to the rolling surfaces though, so it can't be a problem with the angle it hangs in the vinegar. Ah well, as I said before that face will get some weathering paints anyway, so it's no concern. Both wheels now have a matching coat of the nickel, and there is no sign of any plating on the axle -- mission accomplished!

I still have four more of these smaller wheels on the tender, plus four large driver wheels on the loco. It's taking a little time to do each piece, but it already looks far better than the original brass.


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## Fire21 (Mar 9, 2014)

This is fascinating reading of your experiments and successes. I had never even given any thought at all to plating at home...I just had assumed it was a commercial process, and had no application in home use. You've sure expanded my thinking! I cannot think of any place I personally would use it, but I don't know what tomorrow might bring! At least being aware of the potential makes me more prepared. Thanks a bunch!! :smilie_daumenpos:


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## wvgca (Jan 21, 2013)

Glad that it's working out for you ...


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## Shdwdrgn (Dec 23, 2014)

OK so I'm getting a weird result now and looking for ideas. I started working on the four driver wheels this evening. They are all a brass wheel pressed on the a plastic hub. I cleaned each wheel with the steel wool until it was bright and shiny, blow them clean, then do the plating bath. I recharged my batteries, did the first two wheels with great results, then recharged again and did the second pair of wheels. Well on each of the second pair I had to stop because there is a black residue forming. It looks like a good layer of nickel started forming, then this black stuff formed and seems to block the plating process.

So any ideas what this stuff is or what is causing it? It leaves kind of a cloudy finish, almost seems like a fast oxidation process or something. Steel wool won't touch it so I've started sanding with some 600 grit, which is slowly removing it (and of course the nickel) so it will take me some time to get this cleaned up before I can start again. I don't really see anything floating in the bath but it does have a bit of murkiness to it now -- not quite a crystal transparent as when I originally made it. Have I reached some kind of saturation point with the solution indicating it is time to throw it out and make a new batch? Or is it something else?


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## Fire21 (Mar 9, 2014)

You know that I don't know anything about it, but it does sound like something has happened to your solution. If it's murky, then something has gotten into it. Is brass leeching from the wheels into the solution via the acid? I don't know what the costs involved are, but I think I'd try a new solution and see what happens. Good luck!


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## wvgca (Jan 21, 2013)

It's probably depleted... with a low cost solution like this it's easier to make up a new batch


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## Shdwdrgn (Dec 23, 2014)

It's just weird that it would take such a turn right in between wheels. The previous sets turned out just perfect! Yes, it's dirt-cheap to make -- vinegar costs almost nothing and the welding rods cost $11, with enough material in them to make a large number of batches. It's just that if this is the case, I'm rather disappointed in the low volume of parts I was able to make from one batch.


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## Shdwdrgn (Dec 23, 2014)

So I made up a new (smaller) batch of solution today, and giving it a shot now. Initial results are looking good, BUT! So the driver wheels have a plastic hub on one side, and a blackened metal hub on the other side. Obviously there should be conductivity between the axle and metal hub, but not conductivity between the axle and the wheel with the plastic hub... and a check with the multimeter confirms this is true. I currently have the alligator clip connected to the wheel with the plastic hub, there is no overlap from the clip that can be touching the axle. Yes, I've double and triple checked this...

So WHY is the metal hub bubbling like crazy? 10 minutes in, the insulated wheel is looking nicely plated and the unconnected wheel is still a brass color. Checking at 15 minutes, and I once again have this black residue on the nickel plating. There is no sign of any plating on the metal hub, but because of the bubbles coming from it I would assume this is the source of the black residue I am seeing. So how is it possible that an electric current is flowing through the unconnected metal pieces?

Isolating this is going to be a lot trickier. It would be nice if I had a clip that allowed me to turn the piece so the wheel I'm not plating was up out of the bath. I can't paint it like I did with the smaller wheels because the drivers have all the spokes and such molded in, with no easy way to clean the paint out again. Oil, wax, and other coatings would be the same. And whatever I come up with, I still have to be able to also plate the wheel on the metal hub. I'm at a loss!


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## wvgca (Jan 21, 2013)

blackening is usually associated with organic contaminants that accumulate in the solution when it is close to being depleted... and are predominantly relatively even in coverage ..

If the blacking is spotty in appearance, it may be due to a small percentage of zinc in the item being plated .. and the only way that I know of to prevent this is to initially plate the item with copper or brass as a 'sealer' layer .. zinc in a sulfate plating solution is fine however, it acts as a brightener ..but not in an acetate solution such as the one that you are working with .. 

If you have an old DC transformer with 'pulse', you could also try using that, as pulsed power can give a finer grain structure, which gives a harder and shinier final appearance


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## ExONRcarman (Feb 7, 2017)

I know im late but... It is possible you just got a not so pure welding rod. Remember welder produce massive amps that normally would burn off impurities in the rod. The welder himself may not even notice.

As for your amperage issues, i would attempt using a trickle charger as a power source. relatively cheap, and can be picked up at any automotive store. I've seen 2,4,&8 amp chargers. And if it doesnt work, you still have the charger for your motorcycle battery. no loss.


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## Shdwdrgn (Dec 23, 2014)

@ExONRcarman -- that wouldn't explain why the first pieces were turning out just fine. Keep in mind, with this process you leech the nickel into the vinegar first, then once the solution is ready you use the results to plate the brass.

@wvgca -- actually zinc would make perfect sense. Seems to me that is one of the main components of your standard pot metal, of which there are a lot of castings in this kit. It wouldn't surprise me if the metal wheel hubs were also this same metal. As I said, the metal hub was obviously leeching something into the solution, it probably tainted the whole jar, both times.

So now the question is... is there any way to actually 'clean' the solution, or do I need to discard both batches and try yet again?


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## ExONRcarman (Feb 7, 2017)

just a thought, would plating a non essential piece take the impurities out of solution? worth a try?


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## wvgca (Jan 21, 2013)

Once the nickel acetate solution is contaminated with zinc, it's probably done .. 
If you have a zinc constituent in your host piece .. you will quite likely need a copper sealer layer first ...

50% vinegar, 50% hydrogen peroxide as an oxidizer, heat up to almost boiling, and drop in copper wire [household] or pennies, it will turn blue..

then use that solution to copper plate your pieces before nickel plating ..
I ~think~ US pennies after 1982 were not mostly copper, but a copper plating on zinc base material 

I normally copper plated steel pieces not only for a sealer layer, but it also gave a smoother / shiner final plate ..

I normally used 'store bought' plating solutions as they include brightening aents along with suitable carriers and wetting agents..


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## gunrunnerjohn (Nov 10, 2010)

I know many, if not most O-gauge wheels are zinc based, so I suspect the copper layer first is probably how they'd deal with it.


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## CTValleyRR (Jul 26, 2014)

wvgca said:


> I ~think~ US pennies after 1982 were not mostly copper, but a copper plating on zinc base material


Yes, according to the US Mint, you are correct. They are 97.5% zinc and 2.5% copper by weight. They also cost, as of 2012, $0.0241 each to make.


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## Shdwdrgn (Dec 23, 2014)

I went through and cleaned up the pieces I had been having trouble with last night, then got a good plating on them. I also cleaned up the driver wheels and gave them a couple good coats of paint today, which should be ready by tomorrow evening.

I also discovered that the brass rod I was testing with which had a solid black coat from the tainted batches was still able to plate up nicely with clean nickel in the new batch, right over the top of the black. Of course I didn't discover this until *after* I had painstakingly cleaned up one of the smaller pieces that had gotten a black coat, but I guess that's why there were no flaws in the nickel after I re-finished it.

So I've been thinking... is there any danger in tossing the tainted batches down the drain? Basically we're looking at vinegar with some dissolved nickel, so I can't imagine there's anything really hazardous about it?


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## Lemonhawk (Sep 24, 2013)

It's probably OK to dump the vinegar, you just need to remove the nickel first You could check with your water co, but I suspect the metal is a no-no. Around here they have a hazardous chemical pickup every month or so.


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## Shdwdrgn (Dec 23, 2014)

Same photo as I posted under 'other scales', but I finished plating the driver wheels and had a decent shot of the product. The connecting rods between wheels were also plated, but I think the rest of the brass will be getting a coat of 'rusty' paint.









Finally time to paint the base so I can start doing final assembly on the drivetrain!


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## wvgca (Jan 21, 2013)

that plating turned out nicely :thumbsup:


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## Shdwdrgn (Dec 23, 2014)

Well it's certainly not a commercial job, and there's still some pitfalls to learn about. The cast parts were still trying to bleed into the solution even through the paint, so I made a little loop with some copper wire to hold the wheels, and only submerged the side I was working on. There were spots where the plating flaked off, but had a good coating underneath. I cleaned everything up with steel wool and was left with a solid coat of nickel, which looks so much better than the brass. I still need to do the tender wheels, but those will be easy compared to the drivers.


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