@SC45-70 will chime in. First things first. I did manage to silver solder 2 pieces of 0.062" brass plates together to make a 0.124" replacement front sight for an 1860 Army I've been working on for a couple of years. That was uneventful. Cleaned both pieces in acetone and put flux between the plates. Heated the plates until the solder melted due to the heat of the brass. Filed the plate to clean up the surfaces and fit into the slot on the end of the barrel and soft soldered it in place (I need to remove it for the final polish). But the soft solder didn't go as smoothly. I didn't pull the flame away from the work when I tested the solder to see if it was hot enough and must have gotten the flame too close and I melted the solder with the flame. I had a mess to clean up. The gun shot wildly high with the nub of a front sight that was on the firearm when I bought it. I'm going to file it down to shoot point of aim at 25 yards with a 20 grain powder charge for round ball and see where 18 grains with a conical ends up. Enough about the specific task, this thread is about learning how to silver solder. At SC45-70's suggestion I purchased Harris Safety Silv 45. I was unable to locate the recommended Aircosil flux but bought a combination of the Harris Safety Silv 45 and the Sta-Silv flux that came in the package. I have other silver solder I bought at the hardware store but it doesn't disclose the silver content. I also have soft solder if learning is easier with it. I have lots of old steel gun parts and varying thicknesses of brass plate to practice on. I have a standard propane torch as well as an Oxy/MAPP gas torch. What are some good exercises to practice/learn on? Also, the flux that came with the Harris Safety Silv 45 is dry and not 'paste like' as I expected. It can't be applied with a brush. Is it suppossd to be thin enough to apply with a brush? If so, can I thin it and with what? I'm hoping @BBBBill , @Michael Tinker Pearce , @Jim Watson and anybody else who can solder will chime in.