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Post by barbarian on Sept 1, 2016 10:28:42 GMT -5
I was just given one of these, in very nice shape, but with an inoperative shutter. I understand that this is usually due to gummed shutter blades, and that the solution is to wipe them gently with alcohol or naptha. Apparently, there's a difference of opinion as to whether one should remove the front element or the rear element to do this.
Has anyone done this before?
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mickeyobe
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Post by mickeyobe on Sept 1, 2016 10:57:18 GMT -5
I was just given one of these, in very nice shape, but with an inoperative shutter. I understand that this is usually due to gummed shutter blades, and that the solution is to wipe them gently with alcohol or naptha. Apparently, there's a difference of opinion as to whether one should remove the front element or the rear element to do this. Has anyone done this before? Barbarian, I have never done it before but I would suggest taking off the one that is easiest to remove. Then start with a single drop of whatever you use and let it soak for a while. I think the liquid will spread wherever the blades touch each other. Give the shutter a try and repeat judiciously. Don't go overboard with the liquid. Mickey
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Post by barbarian on Sept 1, 2016 13:42:58 GMT -5
Sounds like good advice. I'll give it a try.
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Post by raybar on Sept 1, 2016 17:15:37 GMT -5
I have "unstuck" aperture blades on old Canon R-series lenses this way, using "mineral sprits" (aka petroleum distillates or paint thinner) as my solvent. This would be chemically similar to naphtha, although exactly what it contains is not listed on the label.
I moisten a cotton swab with solvent (just damp, not dripping liquid) and very gently apply it to the blades. The solvent is clear and colorless, and the cotton is white. But as oil is dissolved in the solvent the cotton turns yellow. Once it's yellow, that swab is finished because I don't want to re-deposit the oil it has absorbed back onto the aperture blades. Also, I don't want to use a particular swab very long because cotton fibers can separate from the swab and find their way into places they don't belong. Used swabs go in a fireproof container (an ancient skillet) where they can completely dry before disposal.
I repeat this as many times as necessary to get the blades clean, typically using many swabs over a couple days. It can seem as if it's taking forever, but it's easy and avoids disassembling the lens beyond unscrewing the front elements.
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