I did this one for my A-K Type "M" horn, which was missing its label when I got it. I used a mixture of hydrogen peroxide and hydrochloric acid for the etchant, and cheap semi-glossy photo paper from K-Mart for the toner transfer. Printer used was an HP Laserjet 4000. The template was made using a combination of MS Paint and GIMP 2.6 (which is a free download, and enabled me to "curve" the "MADE IN U.S.A." around the center hole for the mounting screw). The etchant solution I used is cheaper than ferric chloride (and also produces cupric chloride as it etches, increasing the effectiveness of the etchant), but it DOES need to be used in a well-ventilated space. ANyway, here is the finished result:
