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#1 Galvanic coating of the Dunlop "C" cylinders

Posted: Sun Aug 20, 2023 7:17 pm
by Desmo
Hello,

Were the cast iron Dunlop brake cylinders originally zinc or cadmium plated? During the forthcoming overhaul, I would like to restore them to their original appearance.
Thank you for your hints.

Best regards
John

#2 Re: Galvanic coating of the Dunlop "C" cylinders

Posted: Sun Aug 20, 2023 7:45 pm
by Heuer
Cadmium

#3 Re: Galvanic coating of the Dunlop "C" cylinders

Posted: Fri Aug 25, 2023 7:47 pm
by cactusman
Unless you know someone in the aircraft business then cadmium plating is no longer possible (in the UK)...

#4 Re: Galvanic coating of the Dunlop "C" cylinders

Posted: Fri Aug 25, 2023 8:45 pm
by Desmo
... Unfortunately.

Thank you both for your information.

Best regards
John

#5 Re: Galvanic coating of the Dunlop "C" cylinders

Posted: Fri Aug 25, 2023 8:45 pm
by Heuer
Quite a few places in the US, every street corner in India!

Very difficult in Europe although if you look east there will be places. Personally, unless it is on OBL, I would say it is not worth the trouble or expense.

CMC did an early OTS and cad plated everything, including all the handbrake parts you cannot see. Can't remember the cost but it was high.

#6 Re: Galvanic coating of the Dunlop "C" cylinders

Posted: Sun Aug 27, 2023 7:59 am
by cactusman
You could get them zinc plated...it's the std replacement for cadmium where cad plating is no longer permitted (or is prohibitively expensive)..

#7 Re: Galvanic coating of the Dunlop "C" cylinders

Posted: Sun Aug 27, 2023 11:07 am
by Series1 Stu
Zinc plating is what you would get if you sent them away for reconditioning by a reputable supplier. If you're going to strip them yourself and send them for plating make sure your supplier is fully conversant with plating cast iron parts because of the particular pre-treatments required.

Regards

#8 Re: Galvanic coating of the Dunlop "C" cylinders

Posted: Sun Aug 27, 2023 7:25 pm
by Desmo
Hello Julian, hello Stuart,

I have agreed a silver zinc plating with the workshop. The workshop is PastParts Ltd. I got 4 original used cast iron 1/8 Dunlop brake cylinders for the front axle as a possible replacement some time ago. Now that I have decided to overhaul the units belonges to the car, I will offer them for sale. It is interesting that these replacement cylinders were not cadmium-plated but merely blackened or painted black.

John

#9 Re: Galvanic coating of the Dunlop "C" cylinders

Posted: Sun Aug 27, 2023 7:38 pm
by mgcjag
If you go for zinc plating ensure that it has a passivant coat..if not the zinc will go gray and powdery...Steve

#10 Re: Galvanic coating of the Dunlop "C" cylinders

Posted: Sun Aug 27, 2023 8:37 pm
by cactusman
Yes...wise word Steve...

#11 Re: Galvanic coating of the Dunlop "C" cylinders

Posted: Sun Aug 27, 2023 9:56 pm
by Series1 Stu
It's likely to be a clear passivate coating these days so it will be grey/silver in appearance.

Regards