Amazon: DIY Zinc electroplating at home

[fishyboy]

Hi all,
This week I have had my first go some DIY zinc electroplating and I thought you might be interested in the results.

I am using a Zinc plating kit supplied by Gateros Plating, based in the UK (https://www.gaterosplating.co.uk/zinc-plating-kit-5L). The kit has actually sat on my shelf in the garage for the last 3 years and I finally decided lockdown was the ideal time to have a go. Dan at Gateros is a great font of knowledge, always willing to help and also written a easy to follow book on electroplating (https://www.gaterosplating.co.uk/acc...roplating-book).

All of these chemicals must be handled properly to avoid any accidents, especially with the acids. You’ll need the appropriate PPE (Gloves, mask, face shield or goggles) and will end up looking the Walter White in his Crystal Meth lab (Photo 1).

I started with the battery bracket from 1966 Volvo Amazon (Photo 2) for some suitable parts. Most of the original zinc plating had disappeared (the original 25 micron zinc plating is preferentially sacrificed instead of the steel at about a micron a year) and there was local pitting and some rust (I had previously cleaned the components on a wire wheel last year).

My plating set up has an alkaline cleaning bath (to degrease the pieces), an acid dip (to remove any remaining old zinc plating, rust and general muck), electrolysis tank (to do the plating) and a passivation bath (apply the final chromate protective layer). As I was a bit eager and had not set up the cleaning bath or acid dip I substituted these two by a methylated spirit bath to degrease and a HCL acid dip to remove old plating, rust and also act as a pre-plate etch.

As with most things preparation is the key. Poor preparation will lead to a poor plate. Compared to the commercial platters we can probably spend more time on the prep and at least match the professionals products.

For this run I took the bracket parts, which has some surface rust and pitting (Photo 1) and put them into the HCL acid dip. For this I used neat Bostik Mortar and Brick Cleaner which is approximately 20% HCL and available over the counter at places like ToolStation. I left the pierces in the acid dip to chemically clean for 30mins, the washed in water to remove any acid residue. I then gave the pieces a good buffing on a wire wheel to polish up the metal. Next I calculated the surface area of the items and calculated the current required for plating (at a rate of 0.1 Amp/Sq Inch). The parts were then scrubbed with meths (spirit not “crystal”), washed in water, dipped in the HCL solution for one minute to etch the surface, allowing for a better plate, and washed again. The items then went into my electrolyte tank (hung off copper pipe on copper wire – Photo 3) and platted for 40mins. The electrolyte was heated to 25C using a fish tank heater, agitated using a fish tank pump and the current was produced and regulated by a cheap variable power supply off eBay. After another water-wash the pieces were dipped for 40secsonds into the clear chromate passivate (Photo 4) to enhance corrosion resistance. I chose the clear finish over the more modern yellow finish. Once more the parts were given a final water-wash and then hung to dry for 48hrs. Finally, the parts were put back on the Amazon.

I have to say the parts came out pretty good for the first attempt (Photos 5 to 8). While it may not make economic sense in the short term, I think the feeling of satisfaction from doing your own work and with the results being at least on a par with commercial platters, all make it worthwhile. The whole process is within easy reach of most owners

Phil

[142 Guy]

The results look very good. We won't get into the cost effectiveness side of the equation.

HCL / Muriatic acid is an effective rust remover. I have muriatic acid around because I have a 90+ year old solid masonry house that requires repointing on a regular basis. I am a poor mason so I need the acid for cleaning up my sloppy repointing. The muriatic acid which is easily available here is 20 Baume which is more like 30+ % so should be used diluted. Be aware that prolonged dipping can result in hydrogen embrittlement of steel. That is not a problem for things like brackets; but, to be avoided on highly stressed pieces. The biggest problem I have found with using HCL as a rust remover is the flash rusting that occurs after removal and clean up of the piece.

The yellow suits, respirators and vats might have been an interesting sight for any neighbors who spotted you. This didn't precipitate a raid from the local constabulary for cooking up a different kind of 'meth'?

[Army]

Have you tried it on welded repairs yet?

In the classic Land Rover world there are often complaints about vast sums of money spent on hot galvanising only to have very patchy looking finishes.

[XC90Mk1]

That’s rather interesting isn’t it!

[Laird Scooby]

Originally Posted by 142 Guy

Be aware that prolonged dipping can result in hydrogen embrittlement of steel. That is not a problem for things like brackets; but, to be avoided on highly stressed pieces.

Hydrogen embrittlement can be removed by "cooking" the steel in an oven for a period of time, not sure on exact figures but basically by heating it for about an hour at a relatively low heat the hydrogen escapes.

I'm a big fan of electrolytic rust removal using a sacrificial anode of steel, water with some washing soda added and the work piece is the cathode.

I haven't tried zinc plating as yet, just nickel plating. Made a few mistakes but also had a few good results too, not as good as the OPs but that said i was only trying it as an experiment.

The cost of DIY is much cheaper than having it done "professionally" but neither is cheap but still cheaper than renewing and as the OP pointed out, the satisfaction of refurbishing the parts yourself.

[Army]

Hydrogen embrittlement again (!)

On the whole the chances of that happening on these types of car parts is pretty low. Most of these parts are made of a steel with a low carbon content. Hardening (if any) is usually made by work hardening during a pressing process of manufacture.

Those of you who are concerned about hydrogen embrittlement have a butchers here =>

https://en.wikipedia.org/wiki/Hydrog...tlement#Steels

[fishyboy]

Hi all
Some more before and after zinc plating photos of parts from the 131 engine bay.
Phil

[fishyboy]

Hi all
Finished of the dip stick today.
Phil

[Laird Scooby]

Very nice too!

[Vintagewrench]

Nice work on all of your parts and pieces, it sure makes a big difference in the appearance of all of the pieces.

Cadmium plating, not zinc was commonly used on fasteners and small parts on Volvos and other cars up to about 1970. At about that point it fell out of favor because it is extremely toxic, and the plating process polluted the environment, harmed workers, and some of the chemicals and left over cadmium found its way into waste water. It is a hazardous substance and for the most part was banned in the EU and the US by the EPA.

Cadmium is actually extracted from zinc ore and the two metals are related, and share some similarities with mercury.

While preparing parts do not remove it with a wire brush as the dust that results is highly toxic. Learn more at https://en.wikipedia.org/wiki/Cadmium