Metal Casting Zone

Received a variable "high" pressure regulator for LPG (propane) today.The improvement to burner control & output is absolutely incredible.Any caster / furnace user who is using LPG that is naturally aspirated (gas burner in normal air)really should consider this option.Totally recommend!!

Welcome to the forum!
Great tip, anything you can gain more control over is going to help. I use propane with a high pressure regulator, makes a big difference.

I bought a high pressure adjustable regulator. It is the red one rated for 30psi, and 455,000 btu's I believe. I am planning on using it with a 60cfm blower. Any guess as to what size the orifice should be? I was planning on starting with a .050" orifice and go from there.

Howdy,not sure about "orifice" you mention but believe you are talking about gas burner hole size.Of the bunch of different burners I have built they all have number 57 drill bit outlets.No forced air has been used so far BUT the Oliver upwind burners are working famously and the Riel type burners which worked very well with domestic type regulators now require extra forced air.The variable high pressure regulator I have has a maximum working pressure of 400 KPA (4 bar)/60 psi.The best flame for my set up seems to be around 180 KPA / 26 to 28 psi.Hope that,s what you meant & hope it's of help.Hope to have some pics in my profile gallery real soon.Cheers from Aus' Bunyip

With the forced air burner the orifice size isn't an issue. I have a 1/8" copper tube through a hole in a piece of exhaust pipe. I put the blower on the end of the pipe. I have to adjust the air and the gas pressure to get the best heat but I have melted Iron with it on a small scale, about 5 pounds.

If you are using a blown burner, the orifice size doesn't matter quite as much, you adjust the airflow to get a neutral burn. It's critical for an atmospheric or naturally aspirated burner (aka Oliver upwind, T-Rex, Riel-style, etc) because the gas output has to match the tube size and the venturi size etc. It won't function correctly with too large of a gas inlet. It'll run uncorrectably rich.
FWIW the propane inlet on my oil burner(I use it for pre-heat) is just the mashed up end of a copper tube, with a couple of very small holes. Dump the gas into the airstream and voila. Works like a champ.