Does 'black chrome' brass?

[visiondr]

While I've seen Leica's black anodizing become silver around the edges, I've never seen one worn down to the brass. I have read this explanation at Leica FAQ:
"The reason why the cameras with brass top plates in black chrome get "silvery" on the edges instead of braising is because of the nature of the black chrome plating process. It is not a single black chrome plate, but rather a series of platings applied to the metal part. On the zinc top plates, first a flash coat of copper is applied, then nickel plating, chrome plating and then the finish black chrome plating. I believe the copper flash coat was not used on the brass top plates. Since the bright chrome plating is very durable, it is rare to wear past this on the black chrome cameras. Black paint cameras on the other hand do not have these coatings and wear through to the brass rather easily."

So, has anyone here seen a black chrome M actually wear down to brass beyond the chrome and nickel layers?

 

[visiondr]

Yup, that makes sense. However, I was referring to the brass models like the M7, late model M6TTL (last 999) and the M4, M4-2 and early M4-P. That should amount to thousands of cameras out there in the world.

 

[Roger Hicks]

In 25 years or so of hard use on three continents (I bought it new in the early 80s), my M4-P is silvery but not brassy. The black chrome wore so badly in the first 18 months that a Leica dealer friend suggested I return it under guarantee.

For the last 3 years or so it's been my 'second string' to a black paint MP, and my M2 would receive even less use if it weren't for the Rapidwinder on the bottom -- a lovely piece of kit, and the M2 is cosmetically better than either the M4-P or the MP.

Cheers,

Roger

 

[Tom A]

Roger, I agree with the Rapidwinder on the M2 and it is not even a shameless pitch for my own product. It transforms the camera.
The Black Chrome finish used by Leica is called Eloxal. It is a chromium salt and you can do it yourself - if you like cyanide, sulphuric acid and high voltage! The nickel coat provides the "bite" for the salt to attch to as brass is a bit like "oil" when it comes to getting anything to stick to it! When the black chrome wears through, the nickle, which is very smooth, takes a long time to wear through. It can be done as one of my M4P's can attest to - but it takes a LOT of film and looks rather unattractive as you will have black chrome, silver colored nickel and brass in layers. I did paint one of my M4P's with a crackle finish black once it happened.
I think that the original black chrome finish came from Elcan (Ernst Leitz Canada) as it was and still is used for stuff like airplane instrument panels and submarine contol rooms. If you sandblast the material prior to plating it, it has a very low reflection.

 

[visiondr]

Thanks, Tom. That makes a lot of sense. Too bad they don't show the golden hued brass beneath.

 

[Avotius]

I kind of like the worn black chrome myself, but the brass is nice too. The black chrome sure is durable though...thats for sure, takes a lot to wear it. Though I think looking at the rewind crank, its not the same chrome finish, maybe a thinner black chrome that wears easily.