trailmaker
ArboristSite Operative
Carbide chain is not for "normal" wood cutting: used by emergency crews like firefighters or in unusually gritty wood. It needs special files for sharpening- diamond.
Neat advice for when to sharpen, when to throw the chain away. With the PFERD system and a stump vise it's quick and easy to touch up the teeth and rakers after a couple of tanks. For a 20" bar maybe 5 minutes for 2-3 strokes per tooth.
It looks like Stihl makes three different carbide chains. One is specifically for rescue and two are for dirty wood. They require diamond sharpening as you point out.
http://www.stihlusa.com/chainsaws/types.html#RD
Anyonone know the price of the non-rescue carbides? I'd like to give them a try depending on the cost.