Restoration finish of suspension wishbones

[Craig Balzer]

I'm coming to this party a little late an my references are based in the States, but I had my front suspension components cadmium plated. I used Warner Propeller and Governor out of Tucson AZ. The aircraft industry has high standards for plating (of any type) and Brooke enjoys supporting the hot rod/antique car culture

(520) 294-5671
Shipping Address:
P.O. Box 11278,
Tucson, AZ 85734

[Durango2k]

I had mine yellow (gold) zinced some 10 yrs ago. Since doing that I am asking myself wether they might have become brittle, afaik zinc‘ing can make bolts brittle, and you cannot get a 12.9 zinced bolt for that reason. I was also told I should have tempered them just after zincing but now it would be useless to get the H2 out of the structure.

Any metallurgists around? Did Jaguar not know this / or does it not matter ? Or did mankind advance since 1960something and „we“ found out later, literally ?

Carsten

[Craig Balzer]

Durango

What I believe you are talking about is hydrogen embrittlement. I don't know the science behind it but the items need to be heated to several 100 degrees for several hours.

I believe William Angel can best describe / explain the requirements /impacts -- but I don't know if he regularly frequents this forum.

Craig

[Series1 Stu]

Yes, hydrogen de-embrittlement needs to be carried out within about 3 hours of the plating process and is carried out at around 200 to 250 Celsius for around 4 hours, depending on the material.

It's probably a bit late for you Carsten.

[Fspp369]

I’m not sure about “original colours “ but if you go down the plating route be aware of the term “Hydrogen Embrittlement “ I have seen a wishbone with a long crack in it.

Personally I’d go for the best longevity finish..then you know that the next owner gets all of the pleasure from your endeavous… I know some people get hot under the collar about originally, but do you want to drive it or look at it?
If anything I can do to my car enables me to improve its ‘driveability’,safety,reliability, economy, and its time off road then that’s for me! If things look pretty in the process thumbs up

[ReconPilot]

A bit late of for those who desire to "touch up" their suspension components, S3 E-types left the factory with White Cadium plated components. Dick Russ points that out in his book detailing original E-types found un-restored.
CAD plating comes with some cautions. First, the surface must be CLEAN. Best way to accomplish that is by Media Blasting (Glass, etc.). Once cleaned the White CAD plating the components to restore the original finish and look. Finally, after CAD plating ALL suspension components re-plated must undergo a heat treatment to relieve Hydrogen, which leads to Hydrogen Embitterment. Without relieving the parts hitting something like a small pothole may cause a suspension component to break. Not Good.

Here's a excerpt that explains the process:

The ASTM B633-23 Standard for Zinc Electrodeposited Coatings ASTM B633-23 covers material and process requirements for electrodeposited zinc coatings applied to iron or steel articles to protect them from corrosion and consequently extending their service life. The standard specifies that coatings shall be non-alloyed zinc produced by electrodeposition. Additionally, the coatings are provided in four standard thickness classes (i.e., 25 μm, 12 μm, 8 μm, and 5 μm) and one of the following six types of supplementary finishes: As-plated without supplementary treatments With colored chromate coatings With colorless chromate conversion coatings With phosphate conversion coatings With colorless passivate With colored passivate It is crucial to note that, high strength metals, including high strength steels having a tensile strength greater than 1700 MPa (247 ksi, 46 HRC) should not be zinc electroplated in accordance with ASTM B633-23. This is because the pretreatment and plating process can introduce hydrogen that can cause internal hydrogen embrittlement in high strength steels, leading to loss of strength and ductility. The severity of hydrogen embrittlement is a function of temperature—most metals are relatively immune to hydrogen embrittlement, above approximately 150°C. Steels below 1200 MPa (39 HRC) are not susceptible to such embrittlement. In other words, those steels can tolerate the presence of higher concentrations of hydrogen without any delayed degradation of their mechanical strength.

This covers Zinc coating but the same applies if Yellow or Clear (White) CAD plating.

Happy Trails,

Dick