Tried to get their link off the page but it was just empty java. Trade name: Buffing Solution (Rubber Cleaner) will bring up sdsOriginally Posted by B.S.Kumar
Tried to get their link off the page but it was just empty java. Trade name: Buffing Solution (Rubber Cleaner) will bring up sds
Thanks.
Kumar
Thanks Jim, I'll see if I can get some of this stuff.
Well using solvent didn't budge anything so I took out the two screws which allowed me to take off the front external barrel that also has the aperture ring attached to it. This left two cylinders with the aperture blades. I still cannot rotate the blades. To complicate matters the blades are fully closed and some are bulging. I need to be able to separate the to cylinders to clean off the gunk and realign the blades. One half of one cylinder screws into the other. What i have is one smooth black cylinder and the half of the other one which is a ver fine brass thread that had the external barrel on it.
The two cylinder are tight together and can't be budge by hand. Any suggestions on the best way to separate the without doing any damage.
bc
Piece of wood on floor. Piece of rubber inner tube on wood. Barrels on top of rubber. A second piece of old inner tube on top of that, then place your foot squarely over the whole thing and with some weight on it, torque ccw.
Cheers Jim, I'll give that very technical method a go.
This is proving to be more difficult that expected. Cannot budge it with this method either. I'm going to have to resort to more extreme/forceful methods with the chance I will damage the blades (might have already) which will leave me with a lens wide open, not ideal but not a complete disaster.
I'll post some photos of it for people to have a look.
This has become an obsession and case study in perseverance. I've completely dismantled the lens. Some of the blades are warped, bent in places, mighty ugly, my heart sunk to my feet. My first thought was I had ruined this lens as a fully working one. I took a step back and began thinking through the likely ways to fix this, even though I had read this was practically a lost cause.
Without great expectations I began the process of trying to repair the damaged blades which I thought might be impossible given they are so fragile and pliable. With a bit of research on metal work forums I came up with a method of working to straighten then flatten them out. Straightening was simply done by hand to get them as good as I could manually, but still with noticeable kinks in the metal that would make them unusable. Next step was a matter of using a round metal handle of an old salad server to roll over the blade gently, the blade was on a block of hard sponge like material I found on the road so that there was some give when I put light pressure on the blade. That gave me an improved smoothness of the blade but it was now semi curled from the process and still with kinks that were barely noticeable but a problem. Next step was to place the blade on a smooth flat metal surface and run the cylindrical handle over it with minimal but increasing pressure, this was done a number of times, occasionally turning it over. Eventually I had a flat blade again. On the test blade there was a small bur in the inside curve where it was bent. This I removed using a very very fine small well smoothed Arkansas oil stone I've had since a kid in my fishing tackle box.
The test blade appears acceptable, to me at least, using this process, I'll now do the others and re-assemble the aperture and see if I have succeeded in achieving what I thought would be impossible to get it back to working condition. From what I've read it is a challenge to get the blades back into the aperture mechanism, and there is a precise method to lining up the mechanism so it opens and shuts to the f stop it is meant to be at. With this lens I think it relates to lining up the screw hole that holds the inner and outer barrels in alignment. If I get that far then that is the least of my problems.
BC
Bravo. Perseverance pays dividends. If all of the little nubs that fall into the holes and grooves are present I have confidence you'll get it working fine.
After many hours toiling away I've finally got the lens back together. I'll post some photos of the repair work on the DIY thread when I get a chance. Getting all the blades back into place was the most tedious time consuming part of the process but I got there in the end. That's the good news. There still seems to be a problem with opening and shutting the aperture, it's still stiff after cleaning all parts. Is there a special lubricant to use on the aperture mechanism that helps it turn nice and smooth? That's the only thing I can think of stopping it from working perfectly well.
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