Yes, Don, silicon bronze wire melts at a lower temp than carbon steel. It's not as strong as a weld, but it is darn strong and perfect filler for body work. Another benefit is it's not corrosive like steel so no rust. It's a great TIG wire for such work.
As for gas welding, it's really hard to do panels because the flame is less focused. More important to get it in there strong first, then make it pretty. I've had to patch tank floor plates too. I have run SB wire in my MIG and stitched them in. Works week with less distortion. Also keep a damp rag nearby to quench the patch panel frequently to prevent oil canning. A little filler, a little grinding, and Bobs your uncle!