I bought some suction cup handles for my tub/shower walls. One wall is made of smooth tiles, the other less smooth tiles. The stick-on mirrored circle is supposed to be attached and stay on the wall; the hold-on bar has 2 suction-cups that are flattened by using a lever on each cup, supposedly securing the whole handle to the suction cups on each side. I want the handle to be more securely glued to the tiles AND to the cups. What kind of glue is most likely to work with tile and plastic?
Assuming these bars are not used to support the load of a human pulling on them, the typical choice of adhesive in a shower is silicone. As an added benefit, while strong, it is removable by cutting and scraping.
Make sure that both surfaces are clean before gluing and that you have a way to apply pressure (clamping) to the two surfaces. Painters tape might be an option depending on where they are going.