I'm about to re-apply GE kitchen and bath silicone II caulk to the joints between my tub and my ceramic tile on the tub's enclosure walls and between the tub and the ceramic tile floor. I have to re-apply the caulk, because initially I used expired caulk which would not harden. I cut out the few caulk lines which did harden (I had one non-expired tube) and wiped away the greasy, filmy expired caulk from the rest of the caulk lines. Then, I scrubbed the surfaces with the 3M green abrasive pads and with rags moistened with either alcohol or paint thinner. (I don't remember which parts of the caulk cheeks received which solvent.)

Visually and to my touch, I can feel no residue of old silicone alone the joints to be caulked. But when I tried to apply masking tape and painter's tape to the cheeks of the joints, the tape would not adhere. I curled up! Yet, when I apply similar tape to the tile or tub surfaces away from the joint, I get a better adhesion and the tape sticks better to that surface. This test seems to be telling me that there is a silicone residue on the cheeks which prevents the tape from sticking. Again, I cannot feel any sort of residue.

I fear that the fresh silicone may also lack adhesion to the cheeks, just like the tape. There's so much prep work to get to this stage that I don't want the caulk lines to fail to adhere. I guess I could apply more solvent and more scrubbing and re-test for adhesion from the tape... Perhaps I should use a different solvent... Has anyone had a similar experience? Is the tape's failure to adhere to the cheeks of the joint warning me that the silicone will also not adhere??