Step 5: Proper Soldering Technique.
Now everything is ready to solder together! If you've done your prep work properly, this step is easily the most fun.
If you've never soldered copper before, I suggest starting with the columns that will end up vertical, since these don't involve non-standard joints. Use the joint brushes to thoroughly clean the areas to be joined. The copper should be bright and lustrous before you solder. Use the flux brush to apply flux to all surfaces you want to bind together with solder. This means the inside of the fitting AND the outside of the pipe. Then place the pipe inside the fitting, make sure it goes in all the way. Place the part in a vice (wrap it in a towel to avoid marking the beautiful copper) or on the edge of a table. Remember, this copper is about to get VERY HOT.
I've found that trying to flux and solder joints that are far from each other in one soldering run is a bad idea. When flux is heated and not soldered it loses is flux-iness. The joint will need to be re-fluxed or the solder won't flow correctly. If joints are literally right next to each other this isn't a problem.
Fire up the torch and adjust the knob so that the bright blue cone of flame within the outer flame is about an inch long. Touch the tip of this inner flame to the joint, preferably near the lower surface (heat rises). Touch the solder to the OPPOSITE SIDE OF THE JOINT from the flame. The ENTIRE JOINT must be hot enough to melt the solder for the solder to flow, so this prevents making a bad joint. Slowly melt the solder into the joint until one drop of solder falls from beneath the joint. This ensures you have placed enough solder. If you want a clean-looking joint (no solder blobs), quickly (before the solder solidifies) brush the exterior of the joint with the flux brush AWAY FROM YOUR FACE. This will remove the majority of the exterior solder drippage.