LTM Body Finish Technology

[Mustafa Umut Sarac]

I am interested in about learning Leica Tread Mount or FED 1 Body Finish technology. I think acid could be used to finish the bare aluminum in to warm touch pored finish. I want to finish my aluminum - not marine grade - parts to same finish.
Or was material brass and electroplated with a chemical ? Or is it chrome or nickel finish ? I am talking about top part which portholes etc. belongs .

Umut

 

[Paul Goutiere]

To make a nice patina mat finish to aluminum you can use what we call "Lye" or sodium hydroxide (NaOH, also known as 'caustic soda') or "Draino". Mix with a generous amount of water, clean the aluminum well and immerse in the solution. Rinse with lots of water.

BE VERY CAREFUL WITH THE STUFF. IT WILL BURN HOLES IN ALUMINUM, EVERYTHING ELSE AND YOU. USE RUBBER GLOVES, MASK ETC.

I don't know what will make the same patina on brass.

 

[Prof_Pixel]

The process is called anodizing

See http://en.wikipedia.org/wiki/Anodizing#Anodized_aluminium

 

[lxdude]

The process is called anodizing See http://en.wikipedia.org/wiki/Anodizing#Anodized_aluminium

Another method is alodyne (chromic acid), which applied as a liquid, will give a corrosion resistant oxidation finish.

 

[summicron1]

After world war ii british intelligence -- james bond? -- visited Leica and wrote a complete description in some detail of the manufacturing process underway. It includes a description of how they got that specific finish which, I have to say, I do not think they successfully duplicate today. You can find the whole thing here:

http://www.angelfire.com/biz/Leica/page26.html

Specifics of the satin finish are:

25. The satin-chrome finish on external metal parts was

obtained by the following process:-

26. Sandblast, hot cleaner without current, cold cleaner

with current, warm rinse, followed by cold rinse, hydrochloric

dip, copper flash, cold rinse, sulphuric dip, cold rinse, bright

nickel-plate, warm rinse, hydrochloric dip, bright chrome,

drag-out rinse, cold rinse, hot rinse, and dry.

27. All articles were jigged on racks and the racks were

screened to obviate side-throw.

28. The bright nickel tank was approximately 6' x 2' x 21/2',

six depolarised anodes being employed. The volt-meter and

ammeter on the resistance control board were all moving

coil pattern and the tank was worked at 2 volts, 25 amps. No

agitation of the electrolite was employed.

29. The chrome tank was approximately 4' x 2' x 21/2', twenty-

eight strip anti-monial lead anodes being employed. Moving

coil volt and ammeters were also fitted in the resistance board

and the tank was worked at 51/2 volts, 300 amps.

30. It was particularly noted that the time allowed for a

satisfactory chrome deposit was exactly three minutes. All the

plating equipment was spotlessly clean.

 

[lxdude]

. Or was material brass and electroplated with a chemical ? Or is it chrome or nickel finish ? I am talking about top part which portholes etc. belongs .

I don't know for sure, but I would suppose that the Leica top plates of that time were made of brass, and chrome or nickel plated. EDIT: after reading the preceding post, that appears to simply be a 3-stage chrome plating process. Color of the finish will be different than with direct chrome-on-brass plating, because of the layer of nickel beneath the chrome.

 

[summicron1]

and i love this about assembling the shutter:


The main design of the shutter is in no way basically

changed; only slight modification of various components to

suit the new assembly. In the assembly of the shutter fast-

range escapement one component after another was tried till one

was found that worked in a fairly satisfactory manner and then

various minor alterations were made to it by filing, and in

some cases, a light tap with a small watch-makers hammer. The

skill of the operators was undoubtedly the chief asset in the

efficient assembling of this shutter.

 

[Pioneer]

And still my Leica IIIc has chrome peeling off!

 

[summicron1]

And still my Leica IIIc has chrome peeling off!

after 60-plus years, I'm peeling too.

but it still works, right?

 

[lxdude]

And still my Leica IIIc has chrome peeling off!

A funny thing about plating: usually the 3-layer copper/nickel/chromium process will have better adhesion. But on brass, the chrome will adhere well by itself, and its thinness will keep it from flaking off, especially on a satin finish. The thicker finish behaves similarly to paint, in that once it starts to come off, it can peel off. The direct plating is not thick enough to peel.

 

[Pioneer]

after 60-plus years, I'm peeling too.

but it still works, right?

Ohhh yeah. That little beauty works like a charm. I wish all my cameras were that reliable.

 

[lxdude]

Another method is alodyne (chromic acid), which applied as a liquid, will give a corrosion resistant oxidation finish.

BTW, any oxidation finish can give an uneven appearance on cast aluminum, though its protection will still be fine.

 

[SkipA]

The chrome on my IIIc looks great. There is some wear on the top of the shutter button, which has a bright finish instead of satin, with brass showing through. And a little wear on the strap lugs.

 

[lxdude]

The chrome on my IIIc looks great. There is some wear on the top of the shutter button, which has a bright finish instead of satin, with brass showing through. And a little wear on the strap lugs.

I think the wear just makes it look better.

 

[Mustafa Umut Sarac]

Friends, You are awesome. The Intelligence Report find was exceptional. I worked at a electroplating factory as a export manager and cleaning the parts and using distilled water were the two highly critical factors. One Boatbuilder contacted with me to send them yacht handles , I now remember We were using a transparent electroplated shiny coating on them imported from England. There are tons of materials electroplaters could plate on your parts , every kind of color.
I remember I have found a importer from Greece which buys copies of Italian Goods to sell as original at Greece.
We worked hard to match is greenish petrol gold color. But result was breathtaking. The artisans who is responsible from colors , mold cnc stuff were unbeliviable , you say something short and he undertands what you are talking about and did the correct thing in 1 hour.

I will post another question within this thread and thank you very very much.

Umut

 

[Mustafa Umut Sarac]

Electroplating difference between Leica and FED and Turkish Chrome Story

What do you think , is there difference between LTM Copper Nickel Chrome on Brass electroplating technology and FED Electroplated Body Finish.
If they are same - do you think early , after ww2 or late 50s model plating was the best - may be sacrificing a cheap camera small area for thickness measurement is easier than the Leica camera.

But I found a new hobby , is to exact replication of Leica finish. I can may be buy a junk Leica body and test , next summer.

By the way there is no Chrome Ore at Germany and all the Chrome went from Anatolia . Around 40s , you are seeing an Anatolian coating at Leicas.

Umut

 

[Mustafa Umut Sarac]

http://www.l-camera-forum.com/leica-forum/showthread.php?t=255299&goto=newpost


Both the top cover (including the separate rangefinder housings of models II to IIIb, and the housing under the shutter dial of all Leica I and Standards) and the baseplates were of drawn brass. Black finishes were a shiny black etching ground lacquer, probably applied directly without any ground. How Leitz prepared the brass for the chromium plating I don't know; general practice in the surface treatment business seems to be a thin preparatory layer of copper.

Early chroming from about 1933 or so seems to be shinier than later practice. The quality of the chrome deteriorated during the last years of World War II and the early peace years, as Germany had a bad shortage of chromium, which is of course a strategic material. This was the reason behind the dark-grey cameras from the war years.

lars_bergquist

 

[Diapositivo]

I remember I have found a importer from Greece which buys copies of Italian Goods to sell as original at Greece.

 

[Mustafa Umut Sarac]

twenty-eight strip anti-monial lead anodes being employed.

Could you please explain above sentence and technology for me ?

Thank you ,

Umut

 

[lxdude]

I would say that the anodes are lead and antimony, apparently lead alloyed with antimony.

 

[Mustafa Umut Sarac]

The article to be plated is the cathode in an electrolytic bath with an anode as the other terminal.

Chromium Plating

Chromium plating is an electrochemical process in which a uniform layer of chromium is deposited on a cathode. In most plating operations, the anode is made of the material which is to be plated. But chromium plating is the exception because the anode is an inert lead alloy which merely supplies electrons to the solutions. These electrons react with the chromium in the solution to deposit on the cathode.

Pure chromium anodes are too expensive and impractical to use.

Early chroming from about 1933 or so seems to be shinier than later practice

The quality of the chrome deteriorated during the last years of World War II and the early peace years, as Germany had a bad shortage of chromium, which is of course a strategic material. This was the reason behind the dark-grey cameras from the war years.

Therefore, a lead or lead/antimony alloy is used and because of its inert properties, these anodes do not need to be replaced as often as other plating anodes.

from web
Umut

 

[Mustafa Umut Sarac]

For clarification , some points must be indicated. I am running two threads , here and Leica Forum and an heavy cannon as a moderator there confirmed that nickel interlayer between copper on brass and top chromium electro platings effects the chromes color and appereance.

Is there anyway to measure each one of three layers thickness at a lab with sacrifying an lens cap ? How a lab person could to this , straching the cap and measuring the layers with an electron microscope ?

Without going expenses , do anybody knows copper , nickel , chrome layers thicknesses in micron ?

Umut

 

[Mustafa Umut Sarac]

I think Nondestructive Testing with Ultrasonic Inspection could yield a result but I dont know who can do that for ultra thin layers ?

Umut

 

[lxdude]

There is not one single plating thickness per layer that is used universally. I can tell you the chromium layer is usually very thin, compared to the nickel layer. I'm guessing it would not be more than 10 microns. It would be nice if it could be learned if the original plating was done to a standard industry specification, as is usually the case today. Then you could fairly easily duplicate it. I think it is unlikely, though.

These days platers have a range of standard thicknesses they apply to meet different specifications and they can control those thicknesses well.

I suggest you contact a plating shop there, where you live. They should be able to help you. It could be more effective for you to compare plating samples to your Leica than to determine your exact plating thicknesses through other methods. If necessary, they could plate some test pieces of brass for direct visual comparison. An experienced plater might have a good idea of thicknesses, just from examining the finish.
But thickness is not everything. Electroplated nickel can vary in color significantly from a dull gray to a color resembling stainless steel. So, I would expect the specific plating information you now have to be of help to the plater to replicate the original color of the nickel interlayer.
Also, something to consider: The older chrome processes usually used hexavalent chromium which is very toxic. Trivalent Chromium is less toxic and more common today, though hexavalent is still used. The trivalent is easier, and less expensive for the plater to use. It throws better, meaning it forms a more uniform layer, especially on inside corners or on intricate shapes. But its color is different. From what I understand, platers can modify trivalent chrome with additives to make it look like hexavalent chrome.


An electron microscope could be used to determine thicknesses, if you have access to one. Even with that information, it will take some experimentation to replicate the original Leica finish.

Also understand that as a satin chrome piece is handled over time, it will look a little more shiny, as handling polishes the "peaks" while leaving the "valleys" the original finish. So to truly replicate an original satin chrome finish, the sample of the original finish must be an area that gets little contact.

One last idea: maybe you could find someone who specializes in restoring old Leicas, who might already have the information you need, or have the ability to replicate the original finish.

 

[Mustafa Umut Sarac]

Thank you very much Lxdude , this was very informative.
I found a company which is specialized on Boeing , Lockheed parts supplier and electroplating.
I sent them a long mail. They are test lab and production facility located in Ankara. If I can get help from them , that would be great.
Old Japanese Swordsmiths predict the alloy from metal color . I worked as an scanner operator and even 40 years master was not good enough to predict the CMYK of a spot on the drum.
I think I must deal with educated people and test machines.
But DAG and Kreutner could be the resource. This is very good idea.
Do you have suggestions for repair persons to be contacted ?

Umut