Tried a whip head on a really caked flue and it barely touched it
Had a job in Concord last week, two story colonial, flue had about 3 inches of glazed creosote built up from a wood stove the guy ran real hot. I put the whip head on figuring it would knock the glaze loose faster than my old poly brush, and after 20 minutes of spinning it had barely scuffed the surface. Turns out the whip just spun over the hard glaze without biting in, so I switched back to the flat wire brush and did the whole thing in half the time. What do you guys run on glazed flues, a rotary chain or just chemicals and a brush?