Xenotar lens separation?

Nodda Duma said:

I still repair separation. Just haven't been on Photrio lately. I am no longer able to strip and recoat, however. All that stuff is still packed up after moving.

Thing about using heat is that doublets separate specifically because the coefficient of thermal expansion of the crown and flint have a very significant mismatch. Flat bonding surfaces do not reduce the stress induced with heating, and I have seen the soft glass that flints are made of flake like an arrowhead with heat. It is always a risk. Much less risk using a solvent to separate.

p.s. soaking in a 10% sodium chloride (table salt) solution for several days and then wiping clean will remove those old MgF2 coatings if you want to eliminate that damage.

Click to expand...

Nodda Duma said:

I still repair separation. Just haven't been on Photrio lately. I am no longer able to strip and recoat, however. All that stuff is still packed up after moving.

Thing about using heat is that doublets separate specifically because the coefficient of thermal expansion of the crown and flint have a very significant mismatch. Flat bonding surfaces do not reduce the stress induced with heating, and I have seen the soft glass that flints are made of flake like an arrowhead with heat. It is always a risk. Much less risk using a solvent to separate.

p.s. soaking in a 10% sodium chloride (table salt) solution for several days and then wiping clean will remove those old MgF2 coatings if you want to eliminate that damage.

Click to expand...