Hello all. I am new to forging and have a new 2 burner commercial forge. It has an 2-30 psi LP regulator which I adjust to 7-9 psi and a needle valve after it that I open fully after I light it off. It does a good job of heating metal to a yellow heat. I have used a small portable bottle until now.

When I plumbed my forge to a bigger outside 60 gal LP tank for cost savings the problems started. I cut the pressure to 7-9 psi per usual and lit the flame after cracking open the needle valve.
About 1/2 turn of the needle valve the gas quits, the flame blows out and pressure go to Zero on the forge regulator gauge. I can get the pressure back by closing the needle valve.

I suspect a safety feature at the main tank is shutting down the flow but the propane supplier says he doesn't know of one. I just had the supplier make me a "T" off the supply line to a water heater to a shop bathroom. I use this second line for the forge. The "T" is after the big tank regulator by the way. My forge regulator shows the highest pressure coming out of the big tank is about 15 psi. My LP supplier is a nice guy but doesn't want to get into trouble plumbing a hobby shop with high pressure gas, i.e. more than .5 psi. I don't want to get him in trouble or blow up my place either.

Thanks for any help. Chuck of Oriental Ironworks

Welcome chuck!

I'm sure with all the vast experience on this site someone will come up with the fix. A picture of the forge plumbing would help.
As for the supply- you need to have high pressure from the tank. As far as my understanding goes, Propane is high volume and low pressure for household use, something in the 1 to 3 PSI range. I'm not sure how you are getting 15 PSI initially.

A GOOD plumber can get you set up with a high pressure line.

There may be a chance the maker has heard of similiar problems before. There is a chance they may have a suggestion that may help.
Even if you did not buy the forge from them or one of their dealers they may help. They want each forge to work. See wot they say.

You cannot draw through the home appliance regulator, (that's what's running your water heater and must stay in line) tee into the fuel run before that regulator, and install your forge regulator. Or get a separate bottle (tank) for your forge.

A change in cylinder could suggest an inbuilt safety feature in newer cylinders. Its basically a ball valve in the neck of the cylinder and when the flow increases suddenly the ball is pushed up and cuts off the flow. Easily pushed back down with a bit of wire but if you have one of these cylinders you have to increase the flow slowly and it will be OK.

Just something else to think about.