Patrolman previously posted:
"Also need to make sure the compressor is putting out the right PSI."
They also work better when they are warm, and have a drop or two of oil in them. I usually set my regulator at the compressor.
Sometimes breaking a nut loose using PB Blaster and a wrench with a cheater is enough for the impact to finish. Sometimes I have to work penetrant above the nut I just loosened and tighten it again. If my fastener is that special, I'll heat the nut until it glows a dull red color, and work it off by hand until it stops turning, then heat it again to expand the nut.
If I have a replacement fastener in my toolbox, I'd sooner whack it with the gas ax.