Repolishing old lenses with fungus, balsam separation

[Jim C.]

Ok that makes sense now. I took out some of my separated lenses and they look like they've been edge-ground after cementing. So optical alignment is purely angular in a concentric jig. I could technically use the lens body as a jig, after coating with mold release, or the lenses could be held with aluminum tape and aligned with a straight edge. The optical alignment in the video did not look like it required a precision of more that 0.001".

I'm not sure if a vacuum jig can be a helpful air for balsam repair, unless I have the complete optical setup in the promo video.

With re cementing elements back together you're basically working with two elements that have already been optically aligned
and post finished ( edge grinding, etc. ) you just want a jig to hold them in physical aligment to each other for gluing hopefully
preserving the opical alignment.
I still think a hard durometer moldmaking rubber ( shore 50 or higher ) would be your best option. It'll be forgiving with both the glue and in removal.