I have used any number of types of solder with equal success. I have found the resin flux purchased at the hardware store is too thin for the heat you will generate. I also use aluminum square stock to support the barrels on one end (in a vise) and an outfeed roler (for table saw) covered with leather to support the other end. It is just handy, solid and adjustable for height. I have successfully used the cut nails (tapered) and bailing wire but I think the above ideas in that regard are better than my technique. Get lots of solder in when doing the final part and plan on spending the whole weekend cleaning up--the shop and the barrels. (You'll have fun, I'm sure.)
Mark's thoughts on checking for alignment of the ribs before you start the final heat is totally valid too. Invariably, I have to go back and re-set a portion of one rib.
