I have been having a problem getting the right air flow for the propane burner in my foundry furnace. I put a T pipe on the air inlet to give me better adjustment.
I will put a spring held baffle over the end which should allow free flow past the furnace when open but gently force more air down the burner tube as the flow is restricted by closing the baffle. The larger end is just big enough to allow a tight fit for my vacuum hose adapter.
I did the coping for the pipe with my cutoff saw just eyeballing it, it turned out pretty well, no gaps and I was able to get a good weld.
I still have to weld a mount and pivot point for the baffle, I'll do that tomorrow. I plan on another melt tomorrow and will probably take a video of that and post it.
I'm still getting the hang of TIG welding so the welds could be prettier but no blow holes and it isn't going to break.