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Soaking aperture blades into soap water (rust)
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PostPosted: Tue Oct 16, 2018 9:01 pm    Post subject: Soaking aperture blades into soap water (rust) Reply with quote

While running a clean project for my Pentacon MC 50mm F1.8, I put aperture blades in the dish soap too long, they have obvious rust stains; I tried lighter fluid, yes, the stains were removed successfully, but what was even worser, more surface scratches appeared Sad, if that means I will have to run a polish project? don't launch.

I have steel wool(finest), lighter fluid, WD-40 and Brasso Multi-Purpose Metal Polish

Your suggestion is appreciated.


Tuzki with lens

Marco


Last edited by mareinke on Sun Nov 25, 2018 1:29 am; edited 2 times in total


PostPosted: Wed Oct 17, 2018 4:29 pm    Post subject: Reply with quote

I would suggest dissolving rust in vinegar or CLR and then sealing the blades with rust converter. Also, if you are using soap and water to clean the blades you should work quickly, with no soaking. In, out, rinse, wipe, heat.


PostPosted: Wed Oct 17, 2018 4:53 pm    Post subject: Re: polish aperture blades of pentacon MC 50mm F1.8? Reply with quote

mareinke wrote:
While running a clean project for my Pentacon MC 50mm F1.8, I put aperture blades in the dish soap too long, they have obvious rust stains;

Marco



You likely know this Marco, but I hope you don't mind me mentioning it for others. Dish washing soap (if that's what it was) usually includes salt, used as an abrasive. If anyone is obliged to use it, I'd recommend rinsing and drying straight away.


Thanks.


PostPosted: Wed Oct 17, 2018 6:14 pm    Post subject: Reply with quote

I'd use a fine bristle brass wire brush maybe dipped into vinegar. If vinegar is used be sure to rinse with water & dry thoroughly.


PostPosted: Wed Oct 17, 2018 7:22 pm    Post subject: Reply with quote

Hi Gardener,
Thank you for the great suggestions.
It currently looks like


It's a lot of fun to practise my first LENS project.
I will try Rust Converter after the surface cleaning is completely done.

Thanks again.

Marco


Gardener wrote:
I would suggest dissolving rust in vinegar or CLR and then sealing the blades with rust converter. Also, if you are using soap and water to clean the blades you should work quickly, with no soaking. In, out, rinse, wipe, heat.


PostPosted: Wed Oct 17, 2018 7:33 pm    Post subject: Re: polish aperture blades of pentacon MC 50mm F1.8? Reply with quote

Hi Sciolist,
'Mentioning the potential risk for others' is great, I will rename the topic after the issue is resolved.

Sciolist wrote:

You likely know this Marco, but I hope you don't mind me mentioning it for others. Dish washing soap (if that's what it was) usually includes salt, used as an abrasive. If anyone is obliged to use it, I'd recommend rinsing and drying straight away.


Thanks.


PostPosted: Wed Oct 17, 2018 7:49 pm    Post subject: Reply with quote

Hi visualopsins,
Thank you for sharing the experience, I'll try below steps:
1. soak into vinegar
2. rinse with water
3. wipe
4. heat

will update the result later.

Thank you!

Marco

visualopsins wrote:
I'd use a fine bristle brass wire brush maybe dipped into vinegar. If vinegar is used be sure to rinse with water & dry thoroughly.


PostPosted: Wed Oct 17, 2018 8:34 pm    Post subject: Reply with quote

Don't soak, dip in vinegar, clean with brush, rinse, until the rust is gone. If you let it is in aqueous solution for too long you'll only get more rust.


PostPosted: Wed Oct 17, 2018 9:27 pm    Post subject: Reply with quote

Hi Gardener,
Thank you so much for saving me from another accident, I really need to plan everything.

1. dip in vinegar and clean with brush
2. rinse with water
3. wipe
4. heat
5. apply rust converter

Have a nice day!

Marco

Gardener wrote:
Don't soak, dip in vinegar, clean with brush, rinse, until the rust is gone. If you let it is in aqueous solution for too long you'll only get more rust.


PostPosted: Sun Nov 25, 2018 1:21 am    Post subject: Reply with quote



I end up replacing 2 aperture blades (from another for parts P50 1.8 LENS).
Here are the simple rules that do the trick.
Hold the blade with a tweezer, and use a Q-tip moistened with isopropyl alcohol 100%, and slightly wipe the blade in the same direction.
If the blade has stain or rust on it, dip in vinegar, clean with Q-tip, no soak, just clean and dry it, repeat the process until the stain is gone, finally rinse the blade with lighter fluid.

Marco


PostPosted: Sun Nov 25, 2018 1:44 am    Post subject: Reply with quote

Whoo Turtle Congrats Looks great!


PostPosted: Tue Nov 27, 2018 2:24 am    Post subject: Reply with quote

Marco,

Glad you have the blades fixed. I only use alcohol to soak and clean blades.

Another point that's probably worth mentioning. Unlike some other lenses, Meyer/Pentacon automatic lens construction does not have much of a barrier between the iris mechanism and the focussing helicoid. In other words, if you do not thoroughly remove the old grease and put in new, stable grease, the lighter portion of the old grease can get distilled out and re-condenses all over the iris mechanism. I have worked on a few, and not too long afterwards the iris got oily and sticky again if I did not replace the grease.