Saving Old Seagulls

The use of Cadmium plating is not acceptable to some, it does however give a super finish that will outlast many other plating processes.

The finish gives a very nice soft feel satin silver effect.

Cadmium is my preferred choice on the older bikes most the platers do not touch it now, think the only one left
here is at the airport. Have done some white zinc plating at home with good results if the part hasn't been polished it
has that flat cad look.
John

I wonder you never seem see it recommended for use in mixed metal areas, for a salt water environment?

croweater wrote:Cadmium is my preferred choice on the older bikes most the platers do not touch it now, think the only one left
here is at the airport. Have done some white zinc plating at home with good results if the part hasn't been polished it
has that flat cad look.
John

I have just fitted some cadmium plated parts to a spare Villiers carb, still to do would be the choke flap and the petrol banjo.

The flat silver finish gets my vote anyday.

Charles uk wrote:I wonder you never seem see it recommended for use in mixed metal areas, for a salt water environment?

No idea, someone here will know I thought Cadmium would be more salt resistant than zinc. One of my old bikes has been on the road over 40 years she is looking tied now and needs a repaint and chroming but the only nuts, bolts and screws that need replating (Cadmium) are the ones I have changed. What was the original finish on the British Seagulls mine are too rusty to tell? Guess it would have changed over the years inline with the vehicle industry.
John

You're right: cadmium plating is tough stuff and survives well in a salt water environment. Far more robust than zinc, cadmium's also galvanically not too far from aluminium, which helps to make cadmium an ideal plating medium for aluminium components.

Although cadmium eventually fell out of favour due to its well-publicised toxicity, nothing that matches its properties has replaced it, which is why some industries - aerospace for instance - continue to use cadmium.

I prefer well plated nickel. Yes soft and usually under chrome. Something about it though especially on quality hand tools.

If you pamper an old dear while actually using it I am a fan.

Adds a bluish shiny bling that is easy to keep up.

Great for small parts as well.......toggle switch and throttle choke advance retard cable actuators.

I find newly quality chrome somewhat harsh like too much inya face. Especially on older machinery.

For example in that the plumbing on say Anzani, Britannia and early British others as such. All nickle plated.

The lines that polish up very well.......even with the green bits showing through?

All Good aye.

BnC

Chris B, so if you immerse in salt water a Seagull lower unit, that is a cadmium plated drive shaft tube, stainless steel prop shaft, aluminium prop & gear box, which bit becomes the sacrificial anode?

Ignoring the fact that cadmium plating is banned in most of the World except for some military uses due to it's toxicity!

that's one drink I'll not be asking for next time I'm doun the pub........

Contrary to what has been suggested in this thread, cadmium is liked by engineers who design offshore installations, and this affinity is entirely due to cadmium's well established ability to withstand a salt water environment.

Regarding Charles' question about aluminium, stainless steel and cadmium: aluminium is slightly anodic to cadmium and cadmium is anodic to all grades of stainless steel. Zinc, however, is useful because it's anodic to all three.

So if you want to know which bits of your motor are at risk from galvanic corrosion then I suggest you check the galvanic table - and also add a sacrificial anode or, depending on what you're trying to protect, multiples thereof. The latter addition will save you from needing to predict which bit of your engine will dissolve first without one. Add a zinc anode for salt water and magnesium for fresh water.

On the subject of cadmium's toxicity, I'm entirely aware of cadmium's toxicity and I certainly wouldn't recommend using cadmium in any context if a suitable alternative material is available. I will, however, reiterate the point that some industries - most notably those concerned with aerospace and offshore engineering - have failed to find a suitable substitute for cadmium, and therefore continue to use it.

During the war, drive shaft tubes were coated with Zinc finding an SD drive shaft tube with traces of Zinc remaining are a bit like rocking horse droppings. Most have been replaced by chrome plated ones.

The parts illustrated that are now cadmium plated have replaced the nickel plated originals, while I admit the cadmium does look nice, I still think nickel looks better & the thought of the aluminium carb threads corroding when splashed by salt water a little concerning!

If you have the choice choose the silver electro galvanised plated parts over the yellow !

Been away playing with bikes beach Racing. I understand that Cadmium is toxic and we should not use it, what I am
saying it is has a longer lasting finish. What I do not understand is because African Imp Cadmium plated his dive tube
his gearbox will corrode, surely it would corrode the same rate if the drive tube was steel, nickel, chrome or bronze
as they are all more Cathodic than Alloy. I prefer the nickel and chrome finishes but in Oz it costs more than the
outboard is worth so as Cadmium is not available here I might try white zinc plating. The largest user of Cadmium is
the battery industry.

African Imp; any chance you could post images of your bath as it would be the same setup for Zinc plating, just interested.
John

"Sacrificial anode" it's the anode that "corrodes".