Shower Caulking

Here is what I have learned. The shower is probably the only place where the factory uses silicone. Why is beyond me because as you found out when it needs to be repaired, silicone will not stick to silicone nor will any other type of caulk. The only solution is to remove ALL of the old caulk and residue. Get yourself some plastic razor blades and a bottle of caulk remover available at big box stores. Basically the caulk remover is a gel based paint thinner so it will stay it place as it does its work. Between this and the razor blades it will take a majority of it off. When you think you have it all off get some "dust". I used some fine concrete dust to dust the area as this will make it easier to see what areas you missed. As a final removal step get a white scothbrite pad which is a very fine abrasive as you don't want to scratch the plastic. Use this and more caulk remover to get the last bits off. Then you can you any type of bath caulk. Never ever use silicone anywhere.