Pherdinand
the snow must go on
Hi.
While trying to revive a stuck Compur type leaf shutter i noticed the following.
The shutter leaves were not moving but the timer mechanism was nicely and accurately buzzing on slow speeds. The self-timer was stuck. I disassembled the lens and took the shutter out, poured a bit of solvent inside (isopropil alcohol, isopropanol, IPA - a very friendly and clean solvent). The selftimer started to work instantaneously but not the shutter. So i decided to put the whole shutter into ipa and ultrasonicate for a few minutes.
Cleaned up nicely, all the grease from the shutter blades disappeared AND the shutter seemed to work good, except it was still wet so the opening/closing was sluggish.
I decided to quickdry the shutter by using warm air blown on it (heat gun, essentially like a hair dryer, set on warm air and low speed).
When it was dry, the slow speeds got very slow. Now the one second does not ever close, unless i move the shutter speed ring to a higher position.
I repeatedly flushed the shutter after rinsing thus i am more than sure there is no more residue in there. The buzzing of the slow speed clockwork starts nicely bit it stops after a little while.
Question 1: Is it possible, that i heated up the tensioned main spring of the shutter and by the slow cooling down (i was cocking and releasing while drying it) it lost its elasticity being tensioned while warm?
Question 2: Based on the above, what do you think: can i "train" the spring by heating up when untensioned, and quickly cooling down e.g. flushing it with cold solvent while it is warm? just like steel is trained to be more elastic? Could this be a rescueing procedure for old shutters where the spring is "tired" and parts might be difficult to find?
tell me what you think.
While trying to revive a stuck Compur type leaf shutter i noticed the following.
The shutter leaves were not moving but the timer mechanism was nicely and accurately buzzing on slow speeds. The self-timer was stuck. I disassembled the lens and took the shutter out, poured a bit of solvent inside (isopropil alcohol, isopropanol, IPA - a very friendly and clean solvent). The selftimer started to work instantaneously but not the shutter. So i decided to put the whole shutter into ipa and ultrasonicate for a few minutes.
Cleaned up nicely, all the grease from the shutter blades disappeared AND the shutter seemed to work good, except it was still wet so the opening/closing was sluggish.
I decided to quickdry the shutter by using warm air blown on it (heat gun, essentially like a hair dryer, set on warm air and low speed).
When it was dry, the slow speeds got very slow. Now the one second does not ever close, unless i move the shutter speed ring to a higher position.
I repeatedly flushed the shutter after rinsing thus i am more than sure there is no more residue in there. The buzzing of the slow speed clockwork starts nicely bit it stops after a little while.
Question 1: Is it possible, that i heated up the tensioned main spring of the shutter and by the slow cooling down (i was cocking and releasing while drying it) it lost its elasticity being tensioned while warm?
Question 2: Based on the above, what do you think: can i "train" the spring by heating up when untensioned, and quickly cooling down e.g. flushing it with cold solvent while it is warm? just like steel is trained to be more elastic? Could this be a rescueing procedure for old shutters where the spring is "tired" and parts might be difficult to find?
tell me what you think.
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Mael
Established
Your shutter is just running slow because the main shutter spring has lost its strength with decades of using and/or that the speed escapement is not properly adjusted. the main excapement module can be placed in different positions in order to give different speeds.
Overhauling a leaf shutter is a job that must be done in compliance with the repair manual and should not be done with just cleaning it in solvant.
When I personnaly overhaul a shutter, I remove every shutter blades to clean them, replace the main shutter spring, and give lubrication where tit needs too. It is then electronically tested with a shutter tester.
I think you must give your shutter to a technician.
Overhauling a leaf shutter is a job that must be done in compliance with the repair manual and should not be done with just cleaning it in solvant.
When I personnaly overhaul a shutter, I remove every shutter blades to clean them, replace the main shutter spring, and give lubrication where tit needs too. It is then electronically tested with a shutter tester.
I think you must give your shutter to a technician.
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Kim Coxon
Moderator
I think Joe should answer this one. I seem to remember that he is THE expert on blowing blades. Hang on, they might have been iris blades rather than shutter blades. 
Kim
Kim
Pherdinand
the snow must go on
Mael: as i said, the shutter timer was working fine before the drying action. Just the baldes were not opening snappily because of the grease on them. Now they do but the slow speeds are off.
Therefore i doubt the spring lost its strength through the decades.
I know that happens sometimes ("tired spring"), that's why i ask question no 2. Maybe the springs can be recovered.
It is just metal. Not magic, and not something alive that can get old and die.
Since i did not remove the slow speed escapement gear train, or anything other from inside the shutter, it should not be misaligned.
Of course this is not a very important shutter in a super expensive camera. It is just something i am trying to rescue, but it has no real financial value.
My sluggish-shutter rolleiflex e.g. is boxed and goes tomorrow to the repair guy.
A technician is just a technician, not a magician. He knows what he does based on training and experience, and sometimes a repair manual.
I am gathering some experience.
Since i work in experimental nanophysics i don't think i am totally numb in dismantling a shutter, and i am certainly not afraid of very small precision instruments.
Therefore i doubt the spring lost its strength through the decades.
I know that happens sometimes ("tired spring"), that's why i ask question no 2. Maybe the springs can be recovered.
It is just metal. Not magic, and not something alive that can get old and die.
Since i did not remove the slow speed escapement gear train, or anything other from inside the shutter, it should not be misaligned.
Of course this is not a very important shutter in a super expensive camera. It is just something i am trying to rescue, but it has no real financial value.
My sluggish-shutter rolleiflex e.g. is boxed and goes tomorrow to the repair guy.
A technician is just a technician, not a magician. He knows what he does based on training and experience, and sometimes a repair manual.
I am gathering some experience.
Since i work in experimental nanophysics i don't think i am totally numb in dismantling a shutter, and i am certainly not afraid of very small precision instruments.
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Pherdinand
the snow must go on
Kim: which Joe, and why? i guess there's a background story i do not know yet.
BTW thanks for the filter, arrived today!
i guess there's a background story i do not know yet.BTW thanks for the filter, arrived today!
greyhoundman
Well-known
If you remove the slow speed escapement, you can very carefully oil ( Tiny drop) the pinions that ride in the plates. These will cause drag if not given a little lube. They are just a small clock system.
Same for the self timer system.
Same for the self timer system.
Kim Coxon
Moderator
Check out this thread and in particular post 17.
http://www.rangefinderforum.com/forums/showthread.php?t=19596&page=2
Kim
http://www.rangefinderforum.com/forums/showthread.php?t=19596&page=2
Kim
Pherdinand said:Kim: which Joe, and why?
BTW thanks for the filter, arrived today!
FallisPhoto
Veteran
Pherdinand said:
I have almost no doubt that this is what has happened:
1. When you flushed your shutter, the alcohol dissolved the grease. Then it was redeposited when it dried. Now it is on the blades, where it wasn't before.
2. Isopropyl alcohol is not the camera friendly solvent you think it is. This is mainly because it is only (at best) 90% pure. If you want to use alcohol, go to a hardware store and get denatured alcohol. better yet, use naptha. The 10% of other stuff in drugstore alcohol often contains oils.