The gun I have is a 1200 watt Wagner from Wal-Mart. Found it in the paint department for about $24.00. I have found that at the 4" distance mentioned in TBB4 it does take a long time to temper the belly. But, by decreasing the distance to about 2"-3" it does go faster, and I think it still gives the wood a good heat soak because the back of the bow still gets plenty warm by the time the belly turns a nice dark brown color.
Dale