I need to extend the 1/2 " copper supply lines that exist for the shower to accomodate a new bathtub, that will be in addition to the shower. In looking at the current plumbing, it seems to me that the cleanest way to do that would be to remove the old ell's where they go up through the stud wall and replace them with tee's to run the new lines along the floor joists. Are there any issues with heating up the old fittings to remove them, then sweating new fittings in their places? Thanks, Mike