I have found that the very best blue finish for home gunsmiths is the old slow rust process. It take longer, is more labor intensive, but produces the finest finish of any bluing system. All of the fine older double barrel shotguns were blued this way. The investment in equipment is cheap. All you need is rubber gloves, a bag of cotten balls, a fine wire brush, steel wool, a cleaning tank and a hot water tank. It can be done with only one tank. Cheap cookware can be used for small parts and handgun frames. Making steel change color is not hard. The real skill and labor is preparing the surface satin smooth and blemish-free with no rounded edges, dished out holes, or buffed out lettering. That means use no power sanding or buffing tools.