I realize the thread title states ...mount tank WITHOUT brazing... but.... the aluminum rods appear super easy to use with a hand held bottle torch. It can be an easy way to bond aluminum with satisfasctory results.
I was in Harbor Freight yesterday picking up other stuff and saw the aluminum rods...$18.99. I picked up a pack to try out and see if it was junk or really capable of brazing aluminum. I had never used any sort of brazing rod before trying these rods out. It seems to be fairly easy to use. You just have to get the aluminum clean & hot, so the rod flows well. After it cooled, I put the piece in a vice several different ways and whacked it with a small hammer. The welds definitely held tight.
My first attempt held but it looks like I should have put a little more heat on the aluminum before starting. The puddle didn't flow to a feather edge on the bottom piece. I'd think this is because it was not hot enough. It will not take much practice to get the aluminum flowing like it should.
All in all, the rods are very easy to use and looks like it makes a strong enough bond for most things we'd use on the bicycles. It definitely would be suitable for tank mounts.
I'm testing these rods out because I may switch to a felt bike frame with the built in tank. Those frames are aluminum. So I'm hoping these rods will be a suitable option instead of buying a TIG welder for welding small things on the aluminum bike frame when the situation arises.