DAE know that a drop of lighter fluid on a sticky shutter blade can save a $400 CLA?
I was working on a Canon AE-1 for a guy in Portland last week, and the shutter would hang open at slow speeds. I figured it meant a full teardown, which I quoted at $180. But a retired repair guy named Milt who runs a little shop in Beaverton told me to try a tiny drop of lighter fluid on the blade edges before anything else. I did it, cycled the shutter about 50 times, and it fired clean at 1 second and below. Saved the customer $140 and me two hours of work. I had no idea that old lube turns gummy and a solvent flush could fix it without pulling the mirror box. Now I keep a small needle oiler with naphtha on my bench for every sticky leaf shutter that comes in. Has anyone else used this trick on rangefinders or older SLRs, and does it hold up long term or come back in a few months?
The part about "old lube turns gummy" is spot on, I read a long thread on a repair forum years back where a guy who serviced Yashicas said the same thing, that the grease on the slow speed escapement dries out and grabs the blades. He swore by a tiny bit of naphtha on a needle, same as you, and said to work the shutter a bunch right after so the solvent doesn't just sit there and eat into anything plastic. The catch he mentioned is that it's a flush, not a fix, so the gunk is still in there floating around and it can creep back on the blades after a while. Some guys follow up with a hair of proper lube in the right spot once the solvent flashes off, but on a cheap job most just let it ride and tell the customer it might need the real clean down the road. For a $180 quote on an AE-1 that trick is worth trying first every single time, worst case you're out ten minutes.