Has anyone ever baked a lens in an oven before? (Lens Repair - Epoxy Removal)

[FalseDigital]

Since I've gotten this far. I'm thinking of making this a Leica Screw Mount (uncoupled)
Does anyone know where I could buy a leica screw mount ring without a lens attached to it? Does such a thing exist?

 

[retinax]

Congrats on your progress! No idea about the ltm mount except harvesting one from a cheap soviet lens. For removing the epoxy with heat, you'll need really high temperatures. As someone before has mentioned, moderate heating is used to harden the stuff.
Edit: if you manage to convert it to ltm, it will still be rf coupled, the cam remains after all, right?

 

[FalseDigital]

Congrats on your progress! No idea about the ltm mount except harvesting one from a cheap soviet lens. For removing the epoxy with heat, you'll need really high temperatures. As someone before has mentioned, moderate heating is used to harden the stuff.
Edit: if you manage to convert it to ltm, it will still be rf coupled, the cam remains after all, right?

Thanks! I'm not sure as the previous owner grinded off some metal. I'll have to see if the part that touches the focusing lever is still intact after reassembly.

Also, I was thinking that too...maybe a junk soviet lens could be a donor for the mount. However, I'm wondering if it matters if it's from another wide angle lens or not? This is my first time attempting such a thing.

 

[peterm1]

One of the links I gave you mentioned methyl ethyl ketone. It is a bit nasty being inflammable and somewhat toxic but if all else fails its a well known industrial solventthat you should be able to get from a purveyor or industrial chemicals.Other industrial solvents like Xylene may work too - see information in the link below.

This following link is also useful:

http://www.recochem.com/products/paint_thinners_solvents/mekAmongst other things it says:

" MEK is a strong solvent and degreaser. It is excellent for dissolving resin, and adhesives and removing old finishes and contact cement. It can be used for cleaning fibreglass repair tools and for thinning fibreglass resins and is an excellent diluent for lacquer thinners."

Of acetone it also says: "Acetone is a relatively strong solvent and is excellent for dissolving two part epoxies before they set.........." This suggests it will not work so well when the epoxy has cured though I realize you seem to have had partial success.

 

[02Pilot]

Soviet lens might work, but most of their threads are machined into a larger body part. I'd first try an LTM body cap as a source, cutting off or machining out the unnecessary portion.

The other things to consider is that you need to index the lens so the markings are in the correct place, and to make sure the flange-to-film plane distance is correct so that it will focus properly.

 

[RichC]

I did it for a Canon 50mm f1. 2 rangefinder lens a few years back that had balsam separation. Worked perfectly. Dismantled lens, put optics in cooling oven overnight. Job done! Can't recall temperature - I Googled for that

 

[retinax]

Thanks! I'm not sure as the previous owner grinded off some metal. I'll have to see if the part that touches the focusing lever is still intact after reassembly.

Also, I was thinking that too...maybe a junk soviet lens could be a donor for the mount. However, I'm wondering if it matters if it's from another wide angle lens or not? This is my first time attempting such a thing.

This operation is difficult (or may be impossible) for the same reasons that adapting an ltm lens to M is easy - M is wider in diameter and has a shorter flange distance.
First of all this you need to measure if the rear of your lens even fits in a 39mm-minus-wall-thickness hole. Ltm requires the flange to me 1mm further from the film than M-mount. So you will need a mount that will fit on the lens allowing to shim it to the correct flange distance, so it needs to be at least 1mm thinner than the M-mount of the lens.
The mount doesn't have to be wide-angle, that has no effect on the mount.
Like someone said, body caps could be another source. Also lens adapters.

Edit: Come to think of it, this lens was also offered in ltm, so it should be possible, they probably only manufactured a different mount.
Another edit: It looks like the mount has a helical cut right into it? Then now I understand why you think rf coupling may be lost if you exchange the mount. Can it be assembled without the rf cam at all? If that doesn't work, your only chance is buying a broken ltm version or the mount of one.

 

[FalseDigital]

One of the links I gave you mentioned methyl ethyl ketone. It is a bit nasty being inflammable and somewhat toxic but if all else fails its a well known industrial solventthat you should be able to get from a purveyor or industrial chemicals.Other industrial solvents like Xylene may work too - see information in the link below.

This following link is also useful:

http://www.recochem.com/products/paint_thinners_solvents/mekAmongst other things it says:

" MEK is a strong solvent and degreaser. It is excellent for dissolving resin, and adhesives and removing old finishes and contact cement. It can be used for cleaning fibreglass repair tools and for thinning fibreglass resins and is an excellent diluent for lacquer thinners."

Of acetone it also says: "Acetone is a relatively strong solvent and is excellent for dissolving two part epoxies before they set.........." This suggests it will not work so well when the epoxy has cured though I realize you seem to have had partial success.

Thanks for the info. Sadly the link you posted doesn't seem to be working :[

 

[FalseDigital]

Soviet lens might work, but most of their threads are machined into a larger body part. I'd first try an LTM body cap as a source, cutting off or machining out the unnecessary portion.

The other things to consider is that you need to index the lens so the markings are in the correct place, and to make sure the flange-to-film plane distance is correct so that it will focus properly.

Ah! Yeah...a LTM body cap would be a good easy/cheap solution!

Speaking of which....now I'm thinking of buying a Contax G body cap and making it a custom lens for my G1. I normally shoot at 1.5M-Infinity at f/8 so I wouldn't even need to focus. Just adjust it to be the correct scale focus and point and shoot.

Hmmmmmmmmm

 

[peterm1]

Thanks for the info. Sadly the link you posted doesn't seem to be working :[

The link got corrupted when I typed a word after it and the PC read it as part of the hotlink. Try this one its correct. Sorry about that.

http://www.recochem.com/products/paint_thinners_solvents/mek

 

[leicapixie]

Nail polish remover is HIGHLY diluted.
Go to hardware store, soak in that maybe overnight.
Good luck.

 

[FalseDigital]

Peterm1 - Thanks for the updated link!

So although the focusing ring is incredibly stiff I was able to adjust it enough to check focusing. It seems that it no longer reaches the correct length for closer focusing. I'm not sure if this is because it's on a Fuji X or if the previous owner also modified the length of the ring. Really strange stuff...

That being said, I pulled it entirely off and made a cardboard mockup to check the distances. So without the ring I can adjust it. I'm thinking to make a fixed focus of around 1.5m to infinity at f/8 lens with this for Contax G. (just tinkering on the Fujj X for now) I think I can make a mold of the screw and and then make a plastic screw to glue to a Contax G lens cap. Never done that before but since I can finally remove the focusing screw by itself, it shouldn't be too hard.

Here's a photo of my ghetto cardboard mount and a sample photo taken with the lens on an X-E1

 

[Pherdinand]

I prophesy disaster and then I count the cost...

 

[FalseDigital]

I prophesy disaster and then I count the cost...

For LTM or Contax G? Or Both?

My goal isn't to make the lens 100% free focusing again, I'm missing parts for that. I just want to have it at a hyperfocal distance to I can stop it down and use it as a point and shoot with a mounted flash. So I figure, if I measure the distance on a cameras B-Mode with a piece of tracing paper where the film would be, I can check the image focus and then either make a mold or place together some spacers to keep it at the correct distance.

Either way, it's a learning process.

 

[mooge]

RAD.

Hey, if you want any ghetto machining done, shoot me a message.

 

[Puggie]

I might have a proper -G mount in my box of bits. I bought 2 and used one to convert a CV 15mm to g mount. The other must be somewhere. If I can find it, you can have it for postage and a beer.

 

[FalseDigital]

RAD.

Hey, if you want any ghetto machining done, shoot me a message.

I may just take you up on that offer. Thanks!!

 

[FalseDigital]

I might have a proper -G mount in my box of bits. I bought 2 and used one to convert a CV 15mm to g mount. The other must be somewhere. If I can find it, you can have it for postage and a beer.

That would be very helpful! If you find it, I'll definitely take it off your hands! Thanks a bunch!