Cadmium Plating in UK

[christopher storey]

I was asked by richardbtype ( by pm) if I could remember who did this. Since it was many years ago, I could not remember, but I believe they may still be doing it

https://www.poeton.co.uk/advanced-treat ... 0-cadmium/

( I did reply to Richard's pm but he may not have received it so I am posting here, and it may be of general interest anyway)

[Gfhug]

Aren’t these companies only allowed do this work for the aviation industry now? And even if not, judging by their list of clients getting a few parts plated for an E Type might be eye watering expensive.
I’ve seen some companies are now pushing zinc-nickel (or similar) as a more environmentally kind alternative to cadmium for aircraft parts.
Maybe they will offer him that

Geoff

[Phil P]

Cadmium gives superb protection against corrosion, particularly in salt water environments although I don't think many people will be taking their cars out when there's salt on the road anyway.
There has been a move to phase it out under the European and UK REACH regulations. I'm not certain where this is up to but the "Sunset" date ( the date by which it should be eliminated from products) was extended for the aerospace sector. Perhaps someone more current can give an update.
When I came to replate my suspension components a couple of years ago, I was going to use zinc-nickel because of the environmental and toxicological effects of cadmium but an ongoing problem with the suppliers zinc-nickel 'plating tank meant that I settled for zinc. Not quite as good but possibly closer to cadmium in appearance (apart from the black wishbones used on v.early S1 cars which I suspect were black passivated cadmium rather than painted).
The hazards of cadmium in our cars is not as well known as asbestos but can have similar long lasting effects. The main dangers are disassembly of corroded parts where dust may be generated or use of flames to free components.
Phil

[Allrand]

My plater in SA recommended tin plating (he used to work in the aircraft industry) and I'm quite pleased with the results, not sure how durable it will be.
My father was an electroplater in the aircraft industry and plated some parts for my Mk VII many years ago. I'm not very impressed by the durability of cadmium because it's very soft & scratches easily, which then accelerates corrosion. I honestly think modern paints are probably more durable than most plating.



Note the interesting finish to mybrake mc's which were acid cleaned after plating.

[christopher storey]

In answer to Geoff on the permissibility of cad plating, as I understand the position it is permitted on, but only on, those automotive parts that were originally cadmium plated such as E type front wishbones. However, he is right that compared with other processes it is extortionately expensive

[Series1 Stu]

Hi

There is no denying that cadmium provides a superb level of corrosion protection on steel but it is highly carcinogenic and presents a very real risk of damage to the health of those people involved in the process of cadmium plating. Whether it is permitted or not, I do not condone the use of cadmium plating on anything that I am involved in designing and would not consider using it on any of my personal projects.

All of the aerospace and defence products we are involved with are now 100% cadmium free and, as far as I am aware, no new products are permitted to use cadmium plating nor hexavalent chromium (such as used in Alacrom 1200 on aluminium, yellow passivate finish on zinc plated steel and many paint formulations). The only exception to this is on legacy products where the process of re-qualification of such products would be prohibitive. Both cadmium and hexavalent chromium are past their REACH sunset dates with some dispensation existing for the use of Alacrom 1200.

The protection afforded by cadmium plating is impressive but when it is compared to zinc it is usually quoted against unpassivated zinc. However, if you zinc plate and passivate a steel component the degree of protection is increased considerably. The zinc protects the steel in a sacrificial manner but the passivation protects the zinc to a greater extent still. Clear passivation uses trivalent chromium, which is not currently considered to be a health risk.

Be careful not to specify a passivated finish on zinc plated steel parts that are to be subsequently painted as the passivated layer does not provide a key for the paint. Use an etch primer onto the zinc layer.

Use a professional plating company and specify the finish you need and you will get excellent results. Expect to pay for it though.

Regards

[Gfhug]

Stuart, how would you rate electroless nickel plating? Thanks

Geoff

[Series1 Stu]

Hi Geoff

We use electro-less nickel on a few parts but this is usually only to avoid galvanic corrosion on connector plates where nickel plated glands and electrical connectors are used. Generally these are aluminium plates. Such applications are usually protected from the outside environment. I wouldn't use nickel plating for any external applications.

These days, on aluminium, our preferred protections are Iridite NCP and Surtec 650, both of which provide a good key for subsequent paint processes and there is no need to etch-prime. They also reduce the need to keep polishing the aluminium to keep it looking nice. Both are chromate-free. They can be applied by dipping or brushing on. If I was building a lovely aluminium lightweight E Type, I would definitely use either of these to protect the aluminium surfaces. I would paint the external surfaces and leave the internal ones unpainted in the knowledge that they won't go white and fluffy in short order.

The nickel used in the chrome plating process looks lovely but its the chromium that really provides the protection from the elements.

We have put a great deal of effort into finding acceptable finishing processes in the last few years and I really believe that we can get excellent protection without excessive risk to health and environment.

Regards

[Gfhug]

Stuart, thank you. It all helps in planning the next set of plating to be done to various parts, some of which will be painted. It looks like zinc with clear passivation if being left unpainted, but zinc unpassivated then etch primed before painting.

Regards

Geoff

[mgcjag]

Hi Geoff......if your going to paint then why go to the expense of plating first.....shot blast, epoxy prime, then 2k on top.......you can do this yourself quite easily. ......Steve

[Series1 Stu]

Geoff,
That pretty much sums it up. PM me if you want to know what finishing standards and specifications to quote. This applies to wet paint applications, not powder coating, which I wouldn't consider for chassis and suspension components.

Steve,
You are quite correct but doing what Geoff is considering would give much better protection, especially if an etch primer is used first. I suppose it depends on what your requirements are and the budget available. A chip in the paint will start the rusting process in very short order but if there is zinc under there it will protect the steel for much longer.

Horses for courses.

Regards

[Gfhug]

Steve and Stuart, thank you both. It’s for suspension parts and other bits that could pick up stone chips more readily than other areas. A local company did a nice job of zinc plating such parts for me in the past and now planning for more things as needed.

Appreciate all the help and hope this info may be of use to others.

Regards

Geoff