Cadmium plating

[peters3103]

Hi gents,
My front suspension parts recently Cadmium plated. I also had the bonnet balance links and all bonnet catches done. All nuts and bolts were done too. A small rust stain on one of the top wishbones which was there previously is still showing but apart from that I’m happy. I’ve just pressed the bushes in. I think I’ll need to have the upper wishbones fitted with the nylon insert ball joints as mine are a bit worn. I haven’t done any work on the car recently so need some motivation.

[abowie]

The silvery/white colour of Cd is very nice.

Better, and more durable, than bluish Zn.

[cactusman]

Sadly no longer really available here in the UK...Cd plating (other than for some specialist uses) is now banned due to the toxicity of cadmium

[christopher storey]

AFAIK Cadmium plating is still available in the Uk from 2 aerospace sources provided the parts to be plated were originally cad plated. However, the price is very high indeed compared with other platings

[Kember17]

That news is interesting, thank you.

I have bits of my 60s-era Garrard turntable that I am refurbishing that no Garrard specialist will redo with the original cadmium, although it would appear that to do so would actually be legal.

I'm inclined to look further afield on principle as, even in these H&S obsessed days, if ultimately I want to lick cadmium or lead, it really should be my look out, provided I'm suitably informed...

That said, perhaps I should establish the cost before I stand on principle .

[peters3103]

I had settled on zinc until I was advised of a company that still did cadmium primarily for aviation. Interestingly it was cheaper than my quote locally for zinc. Win win (unusual for me!)

[FlyBoy]

Parts came out looking nice but how were they plated? Were they heat treated beginning within 15 minutes of CAD plating to relieve Hydrogen embrittlement? If not properly heat treated (min 4 hours @ 400 degrees F) you may be in for a surprise one day hitting a pot hole. CAD plating is a fantastic surface treatment but stress parts like suspension items must be de-embrittled after treatment. Did you plating firm discuss this process with you? We get enough surprises, don't need to induce more!

Happy Trails, Dick

[peters3103]

Not knowing anything about this process I have no idea. The company I used has done work for an E Type restorer on multiple occasions and they are primarily doing cad for aviation. I trusted them as it is their profession. Hopefully no surprises come my way!

[angelw]

Dick Wrote:

Were they heat treated beginning within 15 minutes of CAD plating to relieve Hydrogen embrittlement? If not properly heat treated (min 4 hours @ 400 degrees F) you may be in for a surprise one day hitting a pot hole. CAD plating is a fantastic surface treatment but stress parts like suspension items must be de-embrittled after treatment. Did you plating firm discuss this process with you? We get enough surprises, don't need to induce more!

Hello Dick,
Zinc Plating is not excluded from Hydrogen Embrittlement and the same rules apply as with CAD plating. Unless the plating company has been operating within a bubble, they would be aware of Hydrogen Embrittlement, particularly those involved with plating aircraft parts, and would take the appropriate steps in the process. However, its always advisable to speak to the company engaged with doing the plating and advise if the part is likely to be sensitive to Hydrogen Embrittlement. Unfortunately, not all those having the parts plated are aware of this condition and therefore, one hopes that the Plating company carry out proper processes.

Regards,

Bill

[FlyBoy]

In this fast moving world today (of business) one has to be one's own advocate. Hoping a reputable company will "do the right thing" is taking a lot for granted. This is especially true if you hit a pot hole, the suspension upright snaps, and you go off exploring the ditch and woods. All I'm saying is be aware, as best you can, of treatments, processes, etc. used in restoring your jewel or components and how the process may affect things down the road. We want to keep our champions on the road as long as possible.
Having spent 43 years in the Aviation side, you quickly understand which re-builder's do quality work and who rebuild at max spec tolerance! So if you're having parts re-plated, ask about specifications, treatments, etc. and keep yourself out of the ditch!!! That's all......

Happy Trails,

Dick

[abowie]

My view on hydrogen embrittlement is that it may be more of an internet forum problem that a real world one.

We routinely zinc plate all fasteners, castings etc on all our restos. We have used the same platers for all that time and I personally started using them in the mid 80's.

Our resto business has been going for over 30 years and I have worked for it for 10. We have had zero problems of failure suggestive of this.

[angelw]

Andrew Wrote:

My view on hydrogen embrittlement is that it may be more of an internet forum problem that a real world one.

We routinely zinc plate all fasteners, castings etc on all our restos. We have used the same platers for all that time and I personally started using them in the mid 80's.

Our resto business has been going for over 30 years and I have worked for it for 10. We have had zero problems of failure suggestive of this.

Hello Andrew,
It's definitely a real issue. The fact that you haven't had a problem may be likened to using a lesser grade bolt where a Grade 8 is specified, but the load thus far hasn't exceed that which the lesser bolt can handle. Or is it a case that the plating company took the initiative and are cooking the parts post plating. Although I normally advise the company I use whether the parts are going to be sensitive to hydrogen embrittlement, they will take the initiative when its clear that the parts should be heat treated, post plating and will ask if unsure and I haven't advised them.

Regards,

Bill

[abowie]

Bill we're just reusing the old bolts so no change of grade.

What sort of problems have you had? Sure it may be that our platers are doing the right thing but this simply hasn't been a problem, at all for a lot of years and a lot of cars.

[angelw]

Andrew Wrote:

Bill we're just reusing the old bolts so no change of grade.

What sort of problems have you had? Sure it may be that our platers are doing the right thing but this simply hasn't been a problem, at all for a lot of years and a lot of cars.

Hello Andrew,
I wasn't implying literally that yours was a bolt issue, I was suggesting that your lack of a problem could be likened to a case where a specified grade of bolt was replaced with a lesser strength fastener and that no issue was experienced because the limit of the replacement bolt had not been exceeded. That does not mean that the system with the lesser fastener is just as strong, it just means its limit has not been reached.

A suspension component that should have been heat treated post plating but wasn't, is unlikely to fail on the vehicles first tentative test drive after assembly. Again, that doesn't mean that the suspension component is just as strong simply because it hasn't failed immediately, it means that the conditions for failure haven't occurred.

Broadly speaking, three requirements for failure due to hydrogen embrittlement are as follows:
1. A susceptible material.
2. Exposure to an environment that contains hydrogen.
3. The presence of stress on the component.

When a stress factor exceeds a specific threshold, sub-critical crack growth occurs when the atomic hydrogen reacts with the metal, leading to failure. Even residual tensile stress within a component can be sufficient to cause failure of an embrittled material.

I haven't had any problem, because I don't take the chance. Any part that may be susceptible to HE I have heat treated post plating. It could well be that I may not have experienced a problem if the parts had not been heat treated after plating, due to the right conditions not being encountered; but I'm not taking the chance.

Regards,

Bill

[Phil P]

I thought that you may like to hear of how I approached Jaguar for materials data to determine whether the suspension parts needed to be embrittlement relieved following 'plating.
With similar concerns as the previous people my thought would be to de-embrittle after 'plating dependent upon the strength; typically needed for steels of strength greater than 1000 megapascals(MPa). As a result, I approached Jaguar Heritage with simple questions. What strength are the components and what was the original tempering temperature specified?
The answer that I received was less than helpful and centred around the fact that I may use the data incorrectly and that Jaguar may then be liable for any failures. I suggested to them that many companies worldwide would be replating parts without even understanding whether they needed to be de-embrittled but this fell on deaf ears. In the end I didn't de-embrittle my parts as they were all less than 1000MPa. However, if the original tempering temperature was over 200 Celsius, a belt and braces post 'plating embrittlement would do no harm. It makes you wonder what third party suppliers of new suspension parts are doing?
Phil