Contax IIa rusty and green chrome removal

[Vintage35]

I'm getting a Contax IIa black dial, it has some rusty areas near the top and I see some greenish powdery oxidation near the edges of the front plate. What is good to remove them as best as possible?

 

[Ranchu]

Ive since used this on a camera, it leaves the rotted part red because of the copper, but it passes and turns brass colored eventually. http://www.rangefinderforum.com/forums/showpost.php?p=2338915&postcount=5

 

[Vintage35]

I was thinking Vinegar for the green areas, what about the rust area?

 

[Ranchu]

Is it really rust? The plate is most likely chromed brass rather than steel? I think the paste will take that off too, it works pretty well. It dries and you can flake it off. You need the salt for some kind of molecule/ion/jimjam transfer, I can't find the original scientific article that I originally read, originally. Is it red because someone already took off the green?

Here is another example..

http://pancakesandfrenchfries.com/2010/09/nontoxic-homemade-brass-polish/

 

[farlymac]

If it looks like that on the outside, I'd hate to think what condition the inside is in. But then some of that may just be from being stored in the leather case. I've heard of Flitz brand chrome polish being used to remove stains and such. But I keep looking at the verdigris around the borders of the rangefinder window, and above the logo, and it makes me wonder how far in that goes. Or if it came out from inside. Granted, Zeiss's chrome wasn't the best back in those days, but this camera is looking for some replacement parts.

One thing, if you have a sonic bath, you can put some Lime Kool Ade mix in water, then run it for a short time to clean off the green. Run it too long though, and it will also take off the chrome. But then you could make your own black paint version.

Good luck with this one, Richard.

PF

 

[Vintage35]

Phil, I haven't opened up the top yet but, it arrived today and I don't think it's as bad as it looks in this image (original eBay listing photo) The rest of the camera is like new, the bottom plate looks new, the inside of the film chamber is very clean, the RF looks good, the shutter slats look like new and it is very quiet. I'll have this one looking good. It functions well too, well worth the $48 I paid for it!

Going to try NevrDull or Navel jelly

 

[D.O'K.]

I don't know about the green, but my lla has something very similar to your front plate "rust". However it's not rust but an area of exposed brass where the chrome plating has worn away. As such, it can't be removed.

The better news is that it shouldn't be an indication of anything wrong within.

Regards,
D.

 

[David Hughes]

Hi,

They told me years ago that the acids used to tan the leather react with the copper and forms copper carbonate, the green muck. Probably other nasties in there as well. Good luck with the treatment.

Regards, David

 

[Vintage35]

I may have a go at one of these "Kits" to electroplate it myself
www.caswellplating.com/

 

[sevo]

"Contax bumps" are on the leather only, on places where the leather covers rivets (some electrochemical reaction between chromed body, brass rivets and leather going on there). The Contax IIa had a excellent chrome plating - if that has worn away, the camera has been exposed to a pretty rough environment. Make sure the damage does not extend inside!

 

[Vintage35]

If you visit the link I posted, the Plug N'Plate kits are quite simple, there is a video to watch. A kit with a transformer and wand and about 8-12 oz. Of solution for $32 is all that is involved. There also is a kit to remove chrome but since, as per the manufactures suggestion, the plating won't stick to chrome, only bare metal, I'm thinking smooth out the rough spots and the plating will stick to the bare spots

 

[Emile de Leon]

Citric acid...(natural...non toxic)...dissolve about 3/4 cup per gallon of h20..soak the part for a few hrs...it gets all bubbly...if it doesn't get bubbly..add more Citric acid..
..and then....presto chango..the rust is all gone...but if the rust has eaten into the metal..there will be some pock marks left where the rust ate into the chrome..rinse in fresh water afterwards..dry part...done..

 

[B-9]

Sorry, I mistakenly thought you wanted to remove all the chrome!

Citric acid works dandy for rust, ill second that motion.

Goodluck!

 

[David Hughes]

Hi,

I call them Leica R Bumps...

Regards, David

 

[Vintage35]

There was more chrome corrosion than I thought https://www.flickr.com/photos/rwrede/sets/72157654296644569 but the brass plating themselves are not corroded or pitted. And better news is the corrosion is only on the exterior. the interior looks pretty good for a 1951. The shutter is working fine.

 

[bucs]

Nice repair notes on the Leica IIIa. Very detailed with images 🙂

 

[Mr_Flibble]

The verdigris (green muck) dissolves quickly in KET alcohol.

 

[Vintage35]

what is KET alcohol? (go ahead and Google "KET alcohol" and you'll see what I mean, come up with "mixing drugs and alcohol and alcohol addiction..etc...)

I was able to clean the green areas with q-tips, then a scraping with my fingernail got the bumps out, leaving the brass plating underneath.

 

[rick oleson]

Once you have it clean, if you polish the exposed brass with Simichrome or a similar metal polish, you'll be surprised how bright it gets.... when I did this on my worn Contax S, I couldn't tell just where the chrome left off and the brass began. Of course, it doesn't stay that bright very long.

I would save the DIY plating kit to try out on an old Sears Singlex or something, I wouldn't make my first experiments on a Contax IIa.

 

[Vintage35]

Thanks Rick, I do believe now, it would be best to polish it first so I'm off to get some polish. I am committed to plate it though, I've seen the brass on this Contax (a rubbed area next to that top right screw on the face plate) and it is indeed very light but definitely a gold color compared to the chrome.