I would like to recaulk between the bathtub and the ceramic-tile wall, but there are many kinds of caulking for sale. What kind should I use?
I just caulked my shower last night. I used GE Silicone II caulk from Home Depot. I read up on this a little before picking out what kind I needed. From what I can tell, silicone caulk is good for bathrooms because:
Another factor which may play into your choice of caulk could be whether or not it's paintable, but the most important factor for a bathroom is going to be waterproof/mold proof.
I just bought a permanent silicone product by GE which is guaranteed to dry in 1 hour and is mold resistant.
I own a remodeling firm, and this is one of those things that so many get wrong and the manufacturers don't tell you how to get right. There are 3 aspects homeowners never hear: 1. All the old caulk HAS to come off. Squeaky clean. 2. All surfaces and substrates to be caulked need to be dry. Bone dry. 3. Use silicone if you must, but silicone or acrylic, the caulk will need to be redone in 2,3 or 4 years, no longer. It just won't last longer.
The dirty secret about silicone is that nothing sticks to cured silicone caulk -- including new silicone caulk. The old silicone has to be completely cleaned off. This usually requires a single-edge razor blade and mineral spirits, followed by an alcohol wipe, followed by a wipe-down with bleach (chlorine or oxygen bleach - the latter being our preference). The last two steps get what the first doesn't; the bleach being very important to kill mold where new caulk is to go. Acrylic caulk, unless it's super hard, is generally much easier to clean-off than silicone.
THEN, before re-caulking, the surface needs to be dry. Bone dry. It really should stand for a day without being used before it's caulked.
As said, use silicone or acrylic, but assume you're going to be re-doing it in 2-4 years, so, for my nickel, I'd rather save my knuckles and knees and use acrylic caulk than crouch in a tub for an hour plus trying to remove all the silicone. Either way, the tub/shower should not be used for another 24 hours.
Do all the above, and you'll have a great finished product -- that will last 2-4 years. Skip a step, and you'll likely find something turning red or black in a matter of days or weeks.
A thorough, well-written article -- with step-by-step detail can be found here: http://www.acmehowto.com/home-maintenance/general/caulk-tub-shower.php
Wish I had better news, but experience has taught us all the above. Good luck.