Adhesive for aluminum to aluminum

Good day all you DIY folks.
I Have adapted a 75mm enlarging lens for use on my Pen F. It has no filter threads but does have a flat rim 2.5 mm wide with a 40mm OD. I have ordered a 30.5 to 43mm step up filter adapter and after I remove the rear threads want to cement it to the flat rim. (All my Pen lenses take 43mm filters and hoods.)
I'm thinking super glue but am worried it would wick to the front retaining ring and onto the front element. I am appealing to the collected wisdom of the group for any suggestions on how to safely cement these two aluminum pieces, if it matters they are both black anodized.
TIA for any suggestions.

I would use a two-component epoxy glue for a situation like this; use the version especially for metals. I use 'Bison Kombi Metal' to glue aluminum parts but there are several other brands.

You can do a test on two dummy parts by splitting a bond after 48 hours to see how it looks. A good bond is thin and after splitting most of the glue must remain on the parts (the glue is split on itself). When a bond is not good the glue is pulled loose from the surface.

Of course it helps to degrease and sand the surfaces beforehand.
During a mount superfluous glue sticking out from the sides can be removed with a damp cloth.

I think your configuration with the two rings is excellent for this type of glue because forces on the bond are small. Another advantage is that you have plenty of time to adjust the parts (unlike super-glue).

Check with: https://www.cyberbond1.com/adhesive-solutions/aluminum-adhesives/

http://www.jeffreyglasser.com/

Thanks for the suggestions. An idea popped into my head (man, that hurts) a few minutes ago. Since the lens is very compact and I'll unscrew it from the focusing mount I'll try gluing the combo with the lens on top, facing down. I plan to make a 'V' wedge fixture out of 1/8 plywood for the adapter ring and setting on top of that a 1/4 in. plywood 'V' wedge for the lens, this should let me center the two pieces. I will try to cement scrap pieces first to see how they hold up. This is what happens from poking around in second hand stores. The lens is a 75mm f3.5 Beslar, a low end 4 element enlarging lens for 6X6. Since it is made to cover 6X6 I figure the center should be fine for the small 35mm half frame negative.