valupak

It was burning/working great for about 5 minutes, then got really loud and hot. Figured it wasn't a good thing. To describe the burner... It is a 2" blower, some 2" PVC with a ball valve, 2" steel pipe 4" long, a 2" T fitting. On top of the T fitting is my gas orifice which is .0625. There is a 6" long piece of 2" steel pipe followed by a 2" to 1.5" reducer. I can attach a picture tomorrow.

Hello all. New to the forum and blacksmithing, but have been working with metal for years. I built a propane forge/burner. It is a forced air burner. It is 2 inches in diameter with a 1.5 inch reducer for a cone at the business end. I fired it up today. It was working great in my forge (softbrick) for about 5 minutes...nice blue flame, nice sound, great flame shape before placing it into the forge, etc. Then suddenly, it sounded like a jet engine. The sound was much louder. I think the flame moved to inside the burner tube instead of outside as the tube started to get hotter. My question is, is this a bad thing? If so, how can I avoid something like this from happening?