I have done this many times in the past, but have never used water, instead used cooking oil. I found that oil held the head (up to about 300F) without burning and you could leave the elements in the oil until everything cooled down to room temp without danger of hurting the glass. The oil also appeared to have some solvent properties that made either balsam or epoxy come off easily. I use either brake cleaner or acetone to clean the lenses once cool, then UV cement to recement. I have a project coming up in the next month to do a hasselblad 120 s planar with front separation.
Obviously works in a pinch, but a more robust method:
100 parts Methylene chloride. 15 parts methanol, and 3 parts ammonia (26% conc) is a gentler / better solvent for removing balsam and uv adhesives. Balsam takes about 1-2 days. Modern stuff takes 1-3 weeks. No risk of thermal shock / stress with this concoction, and a new bond joint will last much longer than reflowing the old. As a lens designer I can say your luck successfully separating as described will not last forever.
Btw re-cementing a lens with UV or other modern adhesive when it originally used balsam may noticeably change the optical performance.. especially true in faster optics. Just so you’re aware. Best to use like-materials to repair.
Speedball India Ink painted on works fine for edge blacking.
Newly made large format dry plates available! Look:
https://www.pictoriographica.com
I've a big Ektar that needs this treatment; where are you getting your Canadian Balsa, Kramer?
On reflection, I think I have a jar of this I bought for use in an oil painting medium.
Does age matter if it's still clear?
Cheers
Methylene Chloride (Old fashioned paint remover) is a very nasty item(for the user) and is no longer available in most parts of the world. And the inclusion of ammonia reminds me that I have lost two lenses to devitrification when using aqueous based separation well away from pH 7!
Canada balsam looses its solvent. - even in well sealed containers. If it remains only slightly yellow, it can be made more fluid (ad libitum) using xylol.
The easiest source of CB is in drop spout equipped small plastic bottles made for slide preparation by microscopists.
There are longer - and better!- threads about separation etc. here. I would describe the first part of this thread as promoting a very dangerous and shoddy method.
How do you know you have lens separation? What does it look like?
Flickr Home Page: https://www.flickr.com/photos/alanklein2000/albums
Newly made large format dry plates available! Look:
https://www.pictoriographica.com
Yes - for modern UV synthetic glues where there are very small distances between the hard glue surface/air space/lens surface.
NO - for Canada Balsam separation. The balsam never becomes a homogeneous solid, so separation is gradual. Some solids are deposited , which can give a general yellowing to the edges.
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