The butyl tape I have is a 3M product, round, probably 5/16" diameter.

Today I got a can of Betaprime Pinchweld and Encapsulation Primer. It says on the can that it's for urethane but the guy in the shop insisted that it was what they use with butyl tape.

How do I use this product? The can is covered with warnings in three languages, but nothing in the way of directions.

I would assume, first remove all of the old butyl from the pinch weld area and clean it thoroughly, probably with lacquer thinner, and allow to dry completely. Then apply the primer, but do I allow it to dry, or work quickly and lay the tape in place while it's still wet? Once the tape is in place, do I apply primer to the glass, where it will contact the tape, to the tape itself, or not at all at the glass/tape contact area? And if primer is needed here, do I wait for it to dry or set the glass while it is still wet? Obviously, the glass will need to be thoroughly clean as well.

After all the glass is in place, go around and around, carefully pushing down, to compress the tape and (hopefully) form a good seal without cracking the windshield, then reinstall the moldings.