M3 with delaminated finder experiment

[Gary Cullen]

I'm new to the list. I'm a retired tech that has been working in the elctro optics field (lasers/holography) since the late 1970's. Before that I was a camera tech and then had my own repair shop for several years. I now do work for friends and local collectors as well as for myself (I collect). What I'm looking for is a Leica M3 with delaminated rangefinder/viewfinder. I have an idea of how to repair them without having them re-silvered. I would clean off the old adhesive and polish off the original semi reflective coating (which gets damaged with the delamination) and try laminating a thin film pellical mirror (taken from an old Canon Pellix or RT) in between the two halves of the RF with UV cure optical adhesive. If anyone has an M3 sitting on the shelf in need of this service and doesn't mind being part of my experiment I will do the job for NO CHARGE. Worst case you get it back as you sent it, best case it works and you have a good working camera again for no charge. Possibly the VF/RF will not be as bright as original but of course it will be much better than blacked out. I've done optical work for Tom Abrahamsson so you're welcome to use him as a reference if you like. Thanks, Gary Cullen (Vancouver, Canada)

 

[sevo]

Well, good luck. I'd be surprised if popping in something at least 0.1mm strong in place of a couple of nanometres would work without adding sigificant parallax to the finder or frame lines.

 

[Ljós]

And first of all, welcome to RFF, Gary!
Your expertise will surely be valued here.

All the best,
Ljós

 

[batterytypehah!]

Well, my project M3 is what you're looking for, but I think I'm with sevo on this. Also, as far as I can tell from the framelines and RF patch, the silver is actually still good on my prism.

I've been debating whether to try re-cementing myself, or pass it to DAG or Youxin (about $150 to $200 for the job).

 

[jasonrutter]

M3

M3

Gary, I have a M3 sitting in my box of stuff with a faint rangefinder. It might be a good candidate for you. I don't use it since it is so hard to focus and have other M bodies I shoot with. I would want to chat with you a little bit about the procedure to better understand it but I am very interested. Its a really early DS model. 703K serial if my memory is right.

 

[Gary Cullen]

I am under the impression the silvering usually gets damaged when it separates but this could vary from camera to camera. It may get damaged when cleaning off the old balsam adhesive as well. Maybe Dag can confirm this as I'm sure he sees a lot of them. For anyone brave enough to try their own re-lamination I would recommend Norland optical adhesive. I've used their products for decades for repairing lens separation and it is excellent.

 

[rlouzan]

Hi Gary,

Welcome to RFF!
I remember you working on my 50mm DR Summicron, you did a fantastic job🙂.

Regards,
Robert

 

[batterytypehah!]

I am under the impression the silvering usually gets damaged when it separates but this could vary from camera to camera. It may get damaged when cleaning off the old balsam adhesive as well. Maybe Dag can confirm this as I'm sure he sees a lot of them. For anyone brave enough to try their own re-lamination I would recommend Norland optical adhesive. I've used their products for decades for repairing lens separation and it is excellent.

All three framelines and the RF patch are complete and perfectly transparent on mine, at the moment this is all I know. It's a back burner, low budget project for me. My first line of attack is hoping that enough balsam is left to just gently warm the prisms until it liquefies again. The camera needs some more parts, and this is by far the most complex repair I've ever tried, so I'm not rushing anything at the moment.

 

[rogerzilla]

I fixed a Minoltina-S RF mirror using the one-way security film sold for vans. It was a brilliant camera until the leaf shutter died.

 

[Gary Cullen]

If I get a camera that only needs to be re cemented (IE mirror coating is ok) I would not try the pellical mirror trick, I would simply re cement it with modern UV adhesive. I should probably be asking for a camera that the finder has gone black, not just hazy white. As far as trying to heat an old rf prism to see if the balsam will re attach, that can be dangerous business, you have to get it quite hot to soften. I usually soak balsam lenses in alcohol for a day or two to get them apart without any heat. That way they come apart with no stress.

 

[normclarke]

I have had success having the prism re-aluminised and then reassembling with the U/V cureing adhesive. The trick is to have the transmission correct at between 30/70 and 35/65. 50% does not work. I found a local (London) source that did the re-aluminising and it worked fine. If you find that after splitting the prism the coating is O.K. then it is all the easier.

Best,

normclarke.

 

[rogerzilla]

CRR split, cleaned (nitric acid) and resilvered the prisms on my M2. Apart from the RF patch being less yellow* than before, you wouldn't know.

*it's not the gold leaf of Leica myth, it's oxidised Canada balsam.

 

[Gary Cullen]

The Canon Pellix mirror is 30/70 so it should work. It's also very thin, I don't recall off hand but it's much less than 1/10th mm. I haven't cut a mirror out of it's frame yet to measure it. What is the cost of a re-silvering/re-laminating job is these days?

 

[tajart]

Hello Gary,
I just want to chime in and tell the group how pleased I was with the beautiful cleaning you did for me on my old rigid 50 Summicron.

Would your experiment work on the M2 as well?

Tom Johnston

 

[splitimageview]

I should probably be asking for a camera that the finder has gone black, not just hazy white.

I have one of these for you.

 

[randolph45]

All three framelines and the RF patch are complete and perfectly transparent on mine, at the moment this is all I know. It's a back burner, low budget project for me. My first line of attack is hoping that enough balsam is left to just gently warm the prisms until it liquefies again. The camera needs some more parts, and this is by far the most complex repair I've ever tried, so I'm not rushing anything at the moment.

Would this work on seperating 2 elements of a shoe mount finder that looks to be fungus trails between elements? Would warm water do this?