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.