corrosion

blindpig · Dec 8, 2013

Hey Y'all,
I'm new here and haven't searched the forum and am not sure if I'm in the right place to ask this question.
Please straighten me out if this ain't the place OK?
I have a 60 plus year old Crown Graphic which hasn't seen the light of day for 10 or more years. When I checked it out the other day,it has some white corrosion type stuff around the back(mostly on the metal parts).Any suggestions as to removing said stuff?
Suggestions will be greatly appreciated.....
Thanks,
Don

Sirius Glass · Dec 8, 2013

Welcome to APUG

Where is the corrosion? Can you post photographs of the corrosion?

Also check out graflex.org for Graflex-Speed Graphic-Crown Graphic questions.

Tom1956 · Dec 8, 2013

I know what white corrosion you're talking about. And the Graflexes sure could get it. Although I have no constructive advice on how to get rid of it outside of re-prepping and re-painting. But good luck finding a paint match because I know of none.

Christopher Walrath · Dec 8, 2013

I concur. To lessen risk to cosmetic damage of the rest of the camera, you would be best to disassemble, or have disassembled by someone who does this at least on a regular basis if you are not sure, and have the affected pieces cleaned. It would not take much, the flick of an applicator brush or some such to get the presumably caustic chemicals that will be needed and have a few drops end up on the bellows or something else that is both vital and not so hardy in substance.

In any event, use caution.

For a paint match, it should not be so hard. So long as the surfaces to be painted are prepped properly the work should be very long lasting. Matching just takes an eye for color. And don;t rely on the lid. Either compare some chips closely or get a few different cans you think might be the ticket and make some chips/panels for use to compare with the original. If you have no examples, you just might need to employ a little creative license.

shutterfinger · Dec 8, 2013

Top Rangefinder or Side Rangefinder? Back removal instructions are the same for all back types used on Pacemakers but the back disassembly is for the Graflok only in this service manual:
http://www.southbristolviews.com/pics/Graphic/manual-pdf/servicemanual.pdf
The back is made of Magnesium.
Brush it off with a stiff bristle brush or a brass wire bristle brush once the back is removed from the body.
See this recent thread for paint suggestions.
(there was a url link here which no longer exists)

gone · Dec 8, 2013

You'd be amazed at what a little elbow grease and a wetted rag can do for a camera's cosmetics. If you're the brave sort, using a touch of bleach w/ the water will help. Others will gasp at this, but I often use a little WD40 and a Q-tip on stubborn areas. There's nearly always enough stuff under the sink or in the pantry in most people's homes to get things all cleaned up again.

bdial · Dec 8, 2013

0000 or 00000 Scotch Bright pads and paste wax work well for removing light corrosion. Use a very light touch if you're working on metals other than steel (as in the case of you're Crown).
(Note, this is a steel wool equivalent grade, it's far finer than the stuff sold for scrubbing pans)

fotch · Dec 8, 2013

Welcome to APUG. Brush is off with a soft brash brush.

David Lyga · Dec 9, 2013

Naval Jelly is sold at most hardware stores and a simple application of it to the corroded area does wonders. Leave it on for about ten minutes and then wipe off with a clean cloth.

First, try this on a tiny part that will not be noticed in case a discoloration is left on the metal. - David Lyga

blindpig · Dec 9, 2013

WOW!
Thanks for the quick comeback and all the help. I'm encouraged and ready to attack this stuff...
Thanks again.
Don

Prof_Pixel · Dec 9, 2013

David Lyga said:
Naval Jelly is sold at most hardware stores and a simple application of it to the corroded area does wonders. Leave it on for about ten minutes and then wipe off with a clean cloth.

First, try this on a tiny part that will not be noticed in case a discoloration is left on the metal. - David Lyga

The metal on the camera that is corroding is magnesium. I would NOT recommend naval jelly; it's for iron and steel!

David Lyga · Dec 9, 2013

Thank you for the 'heads up', Professor Pixel. - David Lyga

Prof_Pixel · Dec 9, 2013

Prof_Pixel said:
The metal on the camera that is corroding is magnesium. I would NOT recommend naval jelly; it's for iron and steel!

I talked with Todd, the technology guru at the GEH, this afternoon and he thinks it's aluminum and not magnesium.

blindpig · Dec 11, 2013

Just got finished removing most of corrosion with vinegar water,the the stubborn spots with straight vinegar. Used a scotchbrite pad a little also.
Letting everything dry overnight then a light touch with fine emory paper and painting (I think).
The metal didn't react by bubbling when hit with vinegar so am sure it's not magnesium, not sure it's aluminum either seems like a zinc pot metal
or something. I don't believe I've ever seen a white thick corrosion on any thing like that except battery posts,so am wondering about some zinc mix.
More to come.....
Don

fotch · Dec 12, 2013

Did you rinse off the vinegar just in case it has some kind of a long term reaction?

railwayman3 · Dec 12, 2013

blindpig said:
The metal didn't react by bubbling when hit with vinegar so am sure it's not magnesium, not sure it's aluminum either seems like a zinc pot metal
or something. I don't believe I've ever seen a white thick corrosion on any thing like that except battery posts,so am wondering about some zinc mix.
More to come.....
Don

I'm no expert, but I believe that zinc alloys were/are used a lot for die-casting of precision parts, models, etc. ?

Prof_Pixel · Dec 12, 2013

Aluminum that is not anodized will produce white corrosion.

blindpig · Dec 14, 2013

Fotch, I'm going to lightly sand/blend the still painted areas to the formally corroded areas then wipe the parts with water,dry,then paint. Am thinking about spray painting with black lacquer then spraying with satin clear coat to replicate the finish. I know it won't have the texture it had originally but think it will be passable.

gleaf · Dec 14, 2013

Be a good idea to 'treat' any area that was in contact with the vinegar with a mild solution of baking soda to eliminate any acid residue. Then a nice rinse with DI water or equal.

blindpig · Jan 5, 2014

I had second thoughts about painting. It seems impossible for me to match whats been there over 60 years so after a light sanding to help blend the areas no longer painted with the areas still painted. I used an aluminum blacking solution used for gun parts to tone down the bare aluminum and buffed it all slightly.Finished it all with a coat of paste wax to resist further corrosion and think it looks OK. It appears a little time worn and rough but it already had some of that look (now a little more so).I feel it looks right. Thanks for all the suggestions....
Don

Christopher Walrath · Jan 5, 2014

Can you post a picture? I always like seeing the end results. Glad it was easily reparable.

blindpig · Jan 6, 2014

Christopher,
Here's a couple of pics.You'll see that it kinda' looks like it's been around the block some.

corrosion

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