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David_nebenzahl
Tinkerer
Username: David_nebenzahl
Post Number: 25
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, December 27, 2009 - 07:37 pm: | 
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First off, I should say that I love polishing cameras. After all the hard work and frustration of doing a repair job, it's like dessert after a meal, buffing up that nice chrome and making it shine.
But I've just been reminded of an annoying problem with polishing, and wondering how others deal with it. I currently use a product called Brasso, made in the US for brass, chrome, etc. It's a mild abrasive in a petroleum base, along with some chemicals to help remove tarnish. Works very well. The problem is that after polishing, it leaves a white powder in any crevices on the thing being polished. Especially things like engravings filled with black paint. Makes them look really dull.
This last time, I was polishing the top plate from my Minolta SRT-101. All the engraving ended up looking pretty chalky. I finally got it out by going over it with a fairly stiff bristle brush and naphtha, jabbing the bristles into the engravings to remove the white stuff. Of course, then you have to remove the solvent and junk with a soft cloth and hope it doesn't mess up the results of all your polishing ...
How do y'all deal with this?
By the way, note to Rick Oleson: I'm planning on getting ahold of some Simichrome and using it. It seems to be available lots of places (if nothing else, you can order it online if you don't mind paying shipping). Maybe it doesn't leave so much residue behind? |
Glenn
Tinkerer
Username: Glenn
Post Number: 733
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 05, 2010 - 08:47 am: |
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Never use Brasso to polish an assembled body or lens! It is ideal to remove scratches in paint work and on un-lacquered alloy parts which are dis-assembled, these can then be cleaned down with naphtha and a tooth brush. If you use Brasso on old lacquered alloy which has been handled a lot, the product will start to remove the lacquer coating - which will have been softened by skin oils and age.
Brasso makes a very good lapping compound for components made to high dimensional tolerances - I have used it to 'smooth' out the operation of lens helicals and shutter gearing etc, especially when the said mechanism has been built up from used parts obtained from a number of scrap items. you should be careful therefore to ensure that no abrasive residue finds its way into the camera interior.
Personally I always clean and polish the parts in the dis-assembled state, the final polishing of the assembled item being a light buffing with 'Renaissance Wax'. This wax polish not only protects the item from finger marks, but prevents corrosion on metal parts and protects leather and leatherette from hardening and cracking - gives a nice sheen to wooden parts and black paintwork also. |
David_nebenzahl
Tinkerer
Username: David_nebenzahl
Post Number: 40
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 05, 2010 - 11:48 am: |
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Well, your points are well taken (I do generally use Brasso only on disassembled parts), but you didn't answer my question, which was what to do about the accumulation of polish in crevices and crannies. Do you have a strategy for that?
My assumption was that these kinds of polishing agents are only used on unlacquered parts (I rarely encounter anything lacquered on cameras; really only found in antique items, like old pneumatic shutters and such). In that case I'd treat it as a painted surface and use something else to clean or polish it. |
Glenn
Tinkerer
Username: Glenn
Post Number: 735
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 06, 2010 - 10:47 am: |
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If one needs to remove dried polish residue from engraving, joint lines etc, wooden cocktail sticks and a selection of tooth brushes are the ideal items. These are what I use to clean up a camera if I am not going to open same up, I modify the tooth brushes by slimming down the heads, bending the handles etc. It is surprising the amount of crud that you can remove by this method from a well used camera. You should also cut down the tip of the cocktail stick so that it just fits into the engraving or knurling, doing this will prevent any damage to the paint infill on the engraved scales etc.
You will find that many early Russian lenses that are in polished alloy mounts are lacquered, rather than being chemically passivated. |
Prasanna
Tinkerer
Username: Prasanna
Post Number: 40
Registered: 10-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 14, 2010 - 01:36 am: |
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The chrome in most cameras is a fairly thin plating. If we use Brasso often it might abrade the plating and expose the base metal. It would be safer to clean the surfaces fully [with solvents like household Ammonia, Windex and clean water], dry and use Simoniz or similar liquid wax to polish and buff with some soft material [Chamois!]. Regards,subbarayan |
David_nebenzahl
Tinkerer
Username: David_nebenzahl
Post Number: 56
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 14, 2010 - 12:22 pm: |
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Again, point well taken, though I don't forsee any such damage using my methods. I generally only polish plated parts once, when I tear down and rebuild the camera. After that it's just a matter of keeping the parts clean.
By the way, I use plain household vinegar (white) to soak metal parts to remove gunk from them. Leaves them clean as a whistle. You can leave parts in for up to a day or so without fear of etching away too much plating. |
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