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lew
2-Dec-2020, 14:57
I need to remove a lens from an old Calumet metal board. Unfortunately the original installer "glued" the retaining ring in place by painting over it with matte black paint. Now it's got to come off without damaging the lens. How should I go about this?

Dugan
2-Dec-2020, 15:35
If it were mine, I would remove the rear lens group, then score around the outside edge of the retaining ring with an x-acto knife, and try to loosen the retaining ring with a lens spanner...if still glued, I'd moisten (not drown) a q-tip with acetone or naphtha and run it around the perimeter of the retaining ring and let it soak in a bit, then try again.

Tin Can
2-Dec-2020, 16:29
I always make sure the shutter and aperture blades are wide open

One slip and they are trash

Wear safety googles too, just in case

Duolab123
2-Dec-2020, 18:20
I always make sure the shutter and aperture blades are wide open

One slip and they are trash

Wear safety googles too, just in case

Good advice on all counts. I was beating on a center punch with a 20 oz ball peen hammer the other day. The punch went boing, still haven't found it, had my face shield on. Shouldn't have to remind people to not be stupid, but I have a sign in my darkroom to wear eye protection when mixing chemicals

Duolab123
2-Dec-2020, 18:33
Pull off the front and rear lens groups, open the aperture wide open, lock the shutter open. If it's really just paint, you could apply a gel paint remover with a Q tip. Buy a lens spanner. I have a Japan Hobby lens wrench works great.
You could chip at it with a sharp wood chisel or a knife. Don't wrench to hard on the shutter or you will break something.
Sounds like a mess.

pgk
3-Dec-2020, 01:16
If it really won't budge then it can always be cut off using a very small cutter in a mini-drill (Dremel or similar) but obviously the retaining ring will be destroyed. Another solution might be to go around the ring with a soldering iron to expand it sufficiently to 'crack the paint progressively around it - I've done this on various things but not lenses, so its merely a suggestion which can be considered (no doubt others will say its crazy but it depends on how careful you can be and what risks you want to take).

Jim Noel
3-Dec-2020, 12:29
If the shutter will unscrew from the ring, remove it so you can attack the ring from front and back.