Vent: A drop of mineral oil on a stuck aperture ring made a huge mess

I had a vintage 50mm lens come in with a really stiff aperture ring. The owner said it hadn't moved in years. Instead of a full teardown right away, I figured I'd try a tiny bit of mineral oil on the ring's seam, just to see if it would free up. Big mistake. I used a single drop from a needle applicator. It didn't just seep in, it wicked right under the ring and got all over the aperture blades. Now the whole mechanism is gummed up and I have to completely disassemble it to clean every single blade, which is a much bigger job. I learned that even a 'safe' lubricant in the wrong spot can cause a real headache. Has anyone else found a better first step for a stiff ring that doesn't risk this kind of mess?

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3 Comments

the_phoenix6mo ago

Ever try to fix a squeaky door hinge and end up taking the whole door off the frame? That's basically what you did. I've had good luck with a tiny bit of lighter fluid on a stiff ring, it evaporates clean. But yeah, oil finds its way into everything.

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the_sean6mo ago

Next time I'll just live with the squeak.

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evan_jenkins5mo ago

Try a tiny bit of naphtha or lighter fluid on a q-tip first, it seeps in way better than oil and evaporates clean with no mess. I've freed up tons of stuck rings that way without ever touching the blades.

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