Harris 56% silver is about $50 from your local welding supply store. You can also use Harris flux but you would be doing yourself a favor to use Stainless Light flux from Cycle Design Group. Stainless Light has indicators built in. As the flux heats up, it beads up then flows out. If you look closely, there are a bunch of little tiny bubbles in the flux. When they go away, the metal is the right temperature to add the silver. If you flick the flame off and onto the area you are heating, you can control the temp as you get there without overheating.
You can use a normal plumbers propane torch for this since the tubing is thin and the brazons are small.
Practice a lot beforehand and you will be fine.