Thanks for the info as I am bilding my first forge I have a few questions. The centrifugal fan I am using is an old blower used for oil cooking fires (Japan). My electrican recomended that I dervirt the unwanted air flow with out blocking the fan as in the sliding knife valve at the forge.he was not keen on fitting a speed controler to the motor. I was thinking of making a diverter valve directing the unwanted air flow into the chineny of the forge through a pipe running internaley up the chimeny for about 700mm this will help the draw, without blowing dust of the floor if I was to dump it under the forge |