Walker S

I’m trying to get into forging and I have a forge built and just trying to get the burner to work. I have about a 16 in pipe with one layer of kale wool and some fire brick on the bottom. When I try to start the burner they either don’t stay on or they don’t burn very good. I’m about 6700 feet what can I do to get them working good. I have already tried drilling holes in the burner pipe to let air in below the welding tip.