I am new to this to begin with. I built my forge from scavenged metal from scrap yard. The fire pot is 8 x 10 x 4'' deep, constructed from 3/4'' flat plate. I drilled 12 -1/4'' holes in a round 3'' circle. My airgate is a slide in a 3''ID, schedule 40 steel pipe. The blower is a welding gas evacuation blower and is pretty strong, I can easily blow large pieces up and out of the fire pot. The airgate seems to be very sensitive to very small adjustments. I get a good fire initially then it begins to burn hollow and as i push it in from the sides of the pot with a shovel as I have seen done on youtube, the fire cools and then I have to open the airgate and soon it is burning hollow again. I am too new to be able to determine if I have #1- too much air velocity do I need a smaller blower?, #2- poor airgate design, would a round butterfly inside the pipe be better to control airflow?. #3- Do I need to shallow up the fire pot to 3'' and drill more holes to lessen velocity? Thanks in advance for any help you may be able to offer..