I have come up with a design, which I think will work: The forge-pan is 1.5 feet across made of a thick steel plate on the bottom, bolted to wooden sides which are about as high as the width of a man's palm. Firebrick, or clay is packed in, with a dip in the middle, which is the fire-pit thing. (The steel plate is exposed by the dip in the middle) There are holes drilled in the bottom of the fire-pit so that ash can fall through. Underneath, to catch the ashes, is a big pipe with an openable /closeable bpttom flap for the ash dump. Then, instead of a bellows, or hairdryer, or whathaveyou, I am going to use an airbed inflator, which is basically a plastic bellows which you step on. This is linked to the ash dump-pipe, so that air can go up through the holes in the fire-pit. The whole thing is on legs.
I hope this will work?
Thanks,
Archie