Archived posting to the Leica Users Group, 1999/09/20
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]In a message dated 9/20/99 3:15:33 PM Eastern Daylight Time, joe-b@dircon.co.uk writes: << Today I found that something has happened to the only Leica lens I ever bought new- the 50mm Elmar-M. The red bump has come off. I have the dislodged red bump safely contained in a film tub and am meditating on re-attaching it. I would be inclined to use cyano-acrylic type "superglue", but I thought it would make sense to ask if anyone has any other better suggestions. It is a chrome lens, if that makes a difference. I hope to be conducting the procedure later today. ;-) Joe Berenbaum >> Cyanoacrylate cements have exceptional compressive strength (remember the commercial with the guy hanging from the cherrypicker by his hardhat?) but much weaker shear strength. Since the most likely cause of red bump dislodgement would be a hit from the side rather than a straight pull, epoxy or even contact cement would probably be better assuming it will adhere to the bump itself. Both are also more likely to withstand extremes in temperature and differences in expansion of the unlike materials than crazy glue which is quite brittle. Another good choice would be the automotive cement which is used to bond plastic moulding trim and weatherstripping to metal. If you do go with crazy glue, keep it and its fumes away from the glass. You would be amazed (and saddened) at the permanent white haze it will impart to the coating. (Don't ask me how I found out. Too painful a story.)