Caulking a drop-in tub

Nine months after my original post I finally have the tub installed. I'm pleased with the installation although I have some variation in the gap I need to caulk caused by the mud bed/tile not being perfectly in plane and some out-of-plane of the tub lip. Biggest gap is perhaps 3/16".

Here's my question: I can probably caulk this directly, since the tub lip is 3/8" thick or so, but is there anything I should consider putting in this gap to provide a backing for the caulk?

Rick

3/16" is not a very large gap. But if you want you can use backer rod. Then caulk over it using G.E. 100% silicone with anti-mildew additive.

Thanks. I've caulked what seems like a million miles of window trim and such. Have heard of backer rod but never run across it. I'm sure I can find some in H* or L***s. I agree I can fill the 3/16" without a "backstop", but using silicone I want to do this in one pass since silicone will not adhere to silicone and if a portion of the gap is just a bit too large I'll wind up trying to fill the entire tub overhag with goop.

If your situation is simply that there's NOTHING on the back of the gap you can fill it with tape... I prefer the yellowish white looking masking tape that is used when painting. You can place it where needed being sure to just hide it real good with caulk.