Master Cylinder Plating

[Tim]

Does anyone know what process/metal was used to plate the master cylinders on early cars? My '61 Traveller has the M/Cs with the hexagonal tops that don't screw off - intermediate between the nut-topped ones and the taper topped ones. They seem to have had a dull grey plating, but after all this time its very hard to tell.

On Nick's site he shows a NOS cylinder with a similar appearance. http://www.min-e-bitz.com/index.php?mai ... cts_id=198

Does anyone know whether there's a plating process that can replicate the finish?

Tim

[graham in aus]

It is an odd looking sort of finish Tim, I'd always thought it was some sort of tin plating, but looking on the net, most tin plating looks bright?

I assume these can type masters are soldered together, the finish is very soft, can be removed / polished with wire wool, maybe it's some sort of lead coating?

[66S]

My plater tells me the original finish was tin and there are varying types of tin plating. In my experience, zinc does not look right at all. Some later replacements were zinc plated.

Regards
Al

[Tim]

I'm starting to wonder whether they were plated before assembly. The tin can part of mine seems to be tin plate with soldered joints. The main body may be plated with something else, perhaps zinc. It doesn't look like the soldered joints have ever been plated over, which would sort of make sense if they plated the body seperately, then soldered the tin can on.

I have a very good, almost new, metal cap and it looks like it was bright tin, its now a bit dull but not grey.

I'm a bit concerned, I don't want them ending up too bright and fake looking, but as this is going to be a bare metal restoration everywhere else, I sort of need to do something with them. Perhaps zinc plating can be treated to make it less bright.

Tim

[66S]

Hi Tim,
Any NOS master cylinders I've seen have been soldered after plating, a good reason to use tin. It solders nicely.

Regards
Al

[andy1071]

Hi Tim,
The reservoirs were soldered on before plating. I think (but won't swear to it) that the finish is a zinc phosphate plating (I don't think it was a cadmium plating, I think Lockheed had stopped using it by then). Later cylinders were zinc passivated plated.

Don't know anyone who can reproduce the finish, but maybe one of the Frost kits can get close. -They also have a number of paint finishes that give quite good representations of plating finishes, but we all know how much brake fluid likes paint....

As the reservoir is soldered on, it should be possible to get a friendly radiator repair shop to remove it: so that an 'S' tank can be transferred to a better cylinder; or the reservoir can be repaired if damaged?

Just for info: the passivated zinc plating either bright/silver, yellow/gold, or olive green/black. Are all basically the same process, the difference being that the 'darker' the colour, the higher the corrosion resistance. The bright being the lowest and olive green the highest.
-I think this has been mentioned before, so I might be sounding a bit like a broken record...

/Andrew

[mk1]

Cadmium gives an identical finish, so I have always assumed its cadmium. Also the cylinders stopped being this colour when Cadmium plating regulations were toughened up. May be coincidental, may not be.

Google Caswell plating products UK for an excellent copy cadmium kit. It's ace, but a bit pricey.