Place the electric soldering iron on the worktable and turn it on.
Lay the copper sheets that you need to solder flat on top of the worktable.
Pour a small amount of liquid rosin solder into the small glass jar. If you apply flux directly from the can, you risk contaminating the entire can of flux.
Lay the Sal ammoniac cake on the surface of the worktable.
Tin the surface of the hot soldering iron. Place the head of the iron on the surface of the Sal ammoniac cake and then melt the lead-free solder on the head of the soldering iron. Rub the solder-covered head onto the Sal ammoniac cake and flip the soldering iron.
Repeat the procedure from the previous step on the other three sides of the soldering iron head.
Dip the acid brush into the small glass jar of liquid rosin acid and brush the two surfaces of the copper sheet that are going to be soldered together.
Lap the fluxed pieces of copper to form the solder joint.
Rest the tinned head of the hot soldering iron on the surface of the lowest piece of lapped copper.
Place the lead-free solder directly onto the head of the soldering iron as you pull the iron across the lapped copper sheets. The liquefied solder will run directly into and over the lapped joint.
Tin the head of the soldering iron before you solder each weld joint to ensure that the solder runs freely into the solder joint.