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01-31-2019, 01:41 AM - 9 Likes   #1
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SMC M 40mm f/28 Teardown + Balsam Separation Repair

I tried my hand at my first lens repair and what I thought was fungus, turned out to be balsam separation (see 12a/b)
For the 40mm, the only "doublet" element can be accessed through the rear of the lens, so dissambling the ring in the front of the lens is unnecessary, unless you have to for your own lens.
As you can see I am not a professional and I know I'll be roasted for the tools used, but that is all I had on hand.

Aside from the tools, you will need an optical adhesive (I bought on amazon) and a UV light (also bought on amazon (bulb only).
To get the doublet apart, I steeped the element in a insulated water bottle with boiling water for about 6-9hrs. I would change the lukewater every few hours with fresh hot water.
When loose enough, I pressed hard against the lens as if rubbing 2 coins together and it slid right off. The old adhesive resembled a contact lens for human eyes...but your lens might be different.
After, I thoroughly cleaned both lens elements with soap and warm water.

For the UV curing, I kept the UV light on for about 2-3 min, which seems to be more than enough as when I tested it on a sheet of paper, the glue was dry in about 10 seconds or less.

Please let me know if you have any questions!



















01-31-2019, 01:58 AM   #2
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Well done! I fear the UV glue but you made it look so easy
01-31-2019, 02:05 AM - 1 Like   #3
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Not bad for a first attempt - you kept the repair area clean and clear. I've seen more advanced technicians workbenches that were covered in dust, debris and half-finished repair jobs.

Wise move on testing the UV adhesive first, many UV adhesives take a long time to bond, while others seem to bond instantaneously when exposed to UV. The UV cement I use has two parts to it: you can alter the ratios of its components to affect the viscosity which can be very useful.


At this point the only advice i'll give is if you buy damaged lenses with the aim to restore them* - you may wish to invest in a proper JIS screwdriver & lens wrench set.


*which can be immensely satisfying, and if you have the time and skill it can also be quite lucrative.

Last edited by Digitalis; 01-31-2019 at 02:14 AM.
01-31-2019, 04:03 AM   #4
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what kind of glue did you use?

01-31-2019, 04:41 AM   #5
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QuoteOriginally posted by shyrsio Quote
what kind of glue did you use?
Have a look at Photo number 1. The name, type and maker is written on the tube.
01-31-2019, 09:11 AM   #6
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Very cool! Descriptive captions for each step with cautions/advice/caveats would be helpful.


Steve
01-31-2019, 10:15 AM   #7
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QuoteOriginally posted by Digitalis Quote
Not bad for a first attempt - you kept the repair area clean and clear. I've seen more advanced technicians workbenches that were covered in dust, debris and half-finished repair jobs.

Wise move on testing the UV adhesive first, many UV adhesives take a long time to bond, while others seem to bond instantaneously when exposed to UV. The UV cement I use has two parts to it: you can alter the ratios of its components to affect the viscosity which can be very useful.


At this point the only advice i'll give is if you buy damaged lenses with the aim to restore them* - you may wish to invest in a proper JIS screwdriver & lens wrench set.


*which can be immensely satisfying, and if you have the time and skill it can also be quite lucrative.
Thanks for suggesting which tools I need in the future. During this repair, I definitely felt the limitations of the tools/things I was working with. I'll keep that in mind, not sure if this will blossom into anything more than fixing personal lenses, but that's good to know there is a market for it!
01-31-2019, 11:20 AM   #8
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Some UV cements tend to glow quite brightly in UV light (so their presence can be detected later on) and can present problems when used as lens cement since the light passing through the lens can make the cement glow which adds a "fog" to the image. Be sure the cement you're using is made for lens (cementing) work. Sound's like the OP had the right stuff as it's described as an "optical adhesive".

The nice part about UV cure is all work to be done to eliminated air voids can be done before the cement sets.

01-31-2019, 12:35 PM   #9
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@jcphoto, you did well on your first repair. Congrats on attempting a slightly difficult job.

And, thanks for documenting and presenting your work. It will be useful to others, I'm sure.

As others have suggested, compatible tools are available, check Amazon, for example. JIS (Japanese Industrial Standard) screwdrivers and 'lens spanners' (for removing element rings, etc) can be acquired at modest cost.


- Craig
01-31-2019, 03:24 PM   #10
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Wow. That's brave of you to sacrifice repair a 40 mm pancake on your first attempt!
02-01-2019, 12:58 AM   #11
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QuoteOriginally posted by jcphoto Quote
not sure if this will blossom into anything more than fixing personal lenses, but that's good to know there is a market for it!
If you're good at something, there is a market for it somewhere.
02-01-2019, 01:31 AM   #12
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Very nice and instructive. Many thanks for this and I hope this will encourage others to share their experiences at repairing stuff.

Last edited by HoutHans; 02-01-2019 at 01:31 AM. Reason: typos
02-01-2019, 02:17 AM   #13
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very nice!!
would you explain again in other words how did you separate the elements? english is not my first language and i can't comprehend what you mean in that part
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