How it's done
Other pirographic artists may have different tools, leather and methods, but I have been doing it my way for 45 years.
I use vegetable tanned cow (Bovine) leather, also called tooling leather. Chrome tanned leather does not work as well. Some vegetable tanned leather burns easier than others - depending on the tanning process.
As tools I use "Stanley" 30 and 45 Watt as well as heavier 75 watt soldering irons. I shorten, hammer and file the tips to suit my hand. Normally, they are shaped like bended, sharpened screwdriver tips. The 75 watt soldering iron is also flattened and smoothed with a file or sanding paper. The smoother, the better. For the grass and leaf effect I make a square tip and file in grooves with a triangular file. The 110 volt "Wood Burning Kit" also does a good job.
I glue the leather onto hardboard (or thin plywood) with contact glue. I then smooth the leather using a smooth wine bottle. This gives me a smooth, hard surface to work on. This also prevents the artwork from being damaged by bending or folding.
The design is drawn directly, in pencil, on the leather before I burn it. Other, more complicated designs are drawn on paper first and then transferred to the leather using black carbon paper.
The outlines are done with the sharp point and the shading with the flat surface of the soldering iron. The more time and pressure in the strokes, the darker the burns. Less time and pressure results in lighter burns. If the tip is too hot, I switch it off and let it cool for a few minutes. It takes a lot of practice.
After the artwork is done, I varnish it with a matt Polyurethane wood varnish. This protects the artwork from water splashes, moisture and dirt. I advise customers to clean their artwork with an aerosol furniture polish/cleaner (like Cobra Touch or Mr. Min) every six months. Spray it on lightly and wipe it off again. This prevents the varnish from drying out and cracking. If the artwork is framed behind glass, no varnish is needed.