Most people who hit flame trouble on a budget gas forge either scrap the burner or throw money at a replacement. What stands out here is the maker doing patient, documented tuning instead, adjusting and testing until the behaviour made sense.
The hardware is a rectangular metal forge sitting on a wheeled cart, with a refractory-lined chamber inside. The burner tube comes up vertically from the top, and there is an adjustable air sleeve on it. Supply runs through a braided metal gas line from a tall white 40# tank, with a regulator assembly and a dial gauge marked 30 PSI.
A couple of details catch my eye. The maker is running at 10 psi, while the operating pressure shown on the gauge sits around 3 to 4 PSI. Firebricks support a dark metal bar at the forge, and tongs and pliers ride along on the cart.
The trouble itself is a good lesson. After the forge had run for about 30 minutes, the flame turned much redder and took on a distinct sound. Earlier, the maker had tried moving the burner nozzle toward center, and realigning the burner afterward cleared the problem up. That sequence, where a well-meant adjustment causes a drift and a realignment brings things back, matches how these burners seem to behave from everything I have read about them.
The maker is still asking for advice on improving the cheap forge, and the tuning story is not finished yet.