Protocol for recementing lens elements

[John Schneider]

I have two lenses that have some separation that I'd like to recement: a Wollensak Series 1a convertible and a 19" Dagor. And now is the right time to do so, as I still have the facilities (reagent-grade chemicals, fume hood, UV lamps, programmable industrial oven, etc.). I've settled on Summers J-91 UV-cure adhesive (thanks to Kevin Crisp), and have the basic knowledge of marking the cells on the rim to maintain proper orientation, using magnets and a steel plate to align the elements by the rim, etc. But in my relative ignorance I don't know how much I don't know. Is there a published protocol etc. that I could use? E.g., should I cement and cure all three elements at once, or only do two at a time?

[Tim Deming]

Hi John,

Having done a few of these (although using Canada balsam), I'd suggest cementing in steps (2 at a time). This will make it easier to align the pieces, and you can always put the part you are cementing close to the light source, rather than having to illuminate through multiple layers of cement.

cheers

Tim

[Glenn Thoreson]

Not having any fancy equipment to work with, I do it this way: First thing upon removing the glass from it's mount, I use a little diamond bit in my Dremmel tool to cut two reference marks on the edge of the glass, about 90 degrees apart. Then it's into a jar of lacquer thinner for a few days until they slip apart.
Next comes a good cleaning, then a drop of cement, line up the reference marks, press 'em together good to spread it and get all bubbles out. Then comes a couple of minutes under the UV light bulb. Good as new, or better. When using UV cure cement, be very careful about what kind of light you work under. With the wrong light you can get a nasty surprise. It's not as easy to get it back apart, either.

[johnschlicher]

What kind of cement to use Glenn?

I have figure out how to get them apart--but I don't know what cement to put them back together

Thanks John

[Pete Roody]

What kind of cement to use Glenn?

I have figure out how to get them apart--but I don't know what cement to put them back together

Thanks John

Steve Grimes has some info on how to get them apart. See:

http://www.skgrimes.com/popsci/index.htm

[sanking]

I have two lenses that have some separation that I'd like to recement: a Wollensak Series 1a convertible and a 19" Dagor. And now is the right time to do so, as I still have the facilities (reagent-grade chemicals, fume hood, UV lamps, programmable industrial oven, etc.). I've settled on Summers J-91 UV-cure adhesive (thanks to Kevin Crisp), and have the basic knowledge of marking the cells on the rim to maintain proper orientation, using magnets and a steel plate to align the elements by the rim, etc. But in my relative ignorance I don't know how much I don't know. Is there a published protocol etc. that I could use? E.g., should I cement and cure all three elements at once, or only do two at a time?

I don't know if there is enough detail for you but there is a page on the S. K Grimes site about re-cementing lenses. http://www.skgrimes.com/popsci/index.htm

S.K. Grimes no longer offers this service but the article may be of some use to you.

BTW, I once had Paul Ebel re-cement a lens for me. He did a nice job for a reasonable price.

Sandy King

[Glenn Thoreson]

What kind of cement to use Glenn?

I have figure out how to get them apart--but I don't know what cement to put them back together

Thanks John

John, I use UV cure cement from Edmund Optics.
The label on the bottle says: Type J-91 Lens Bond Optical Cement. It is made by Summers Optical of Hatfield, PA. They have a web site:
www.emsdiasum.com
Phone: (215) 412-8380
Be aware that working in light with even a small amount of excess UV can cause this stuff to set up in an instant. Good stuff.

[Mike1234]

I've heard that some of the UV cements can turn yellow with age and/or repeated exposure to light. Anyone know which ones don't?

[IanG]

I've heard that some of the UV cements can turn yellow with age and/or repeated exposure to light. Anyone know which ones don't?

I think your referring to certain lenses like the early Pentax Takumar 50mm f1.4's which have glass that yellows and can be corrected by exposure to UV or bright sunlight.

The balsam cemented turns yellow with separation with some early lenses.

Ian

[John Schneider]

I don't know if there is enough detail for you but there is a page on the S. K Grimes site about re-cementing lenses. http://www.skgrimes.com/popsci/index.htm

S.K. Grimes no longer offers this service but the article may be of some use to you.

THAT'S the webpage I was looking for. I've been racking my brain to find that page, and for some reason I never thought to search the SK Grimes site.

A quick search of the MSDS shows than Canadian balsam is soluble in xylene (which I use in my research and have plenty of), so I'll try that first, rather than heat. I also have a laminar flow hood in my area I can use, so it looks like I'm all set to go. I have one cell of a Dagor that I'll practice on before I try to recement something good. Thank you to everyone for your help.