Thread: new forge

This style of venturi burner works better with a lot of pressure behind the orifice. The high speed gas jet entrains air via vacuum as it is sent down the pipe. Internal turbulence will mix the air/gas and the magic happens at the burner end. Getting the right balance of air and gas has been calculated. Ron Reil was one of the first to publish a good deal of it. The balance is achieved by orifice size against the size of the air holes against the diameter and length of the tube. If you make the air holes too big, a choke tube is handy.

MIG tips are useful as they are already threaded, but the size of the orifice can be a little off. They might be designed for an 0.035 wire which means they may be 0.040 to allow the wire to pass through without dragging. I drill all mine. Even so, if you are observant and realize you may have a little more gas than you want, you adjust the air intakes and off you go. I'd recommend starting small and working up though.

The rest of the business of running one of these is no different than tuning a wind instrument.

I have been doing some research on building my own forge. Running straight from the tank sounds like a great money saving idea beside the fact that it works better. I am wondering about the safety factor in doing this. Like Charlie's valve is hooked up with a hose clamp. That kinda scares me. He is still around so I assume it has worked so far but I think I would use a little more secure fitting and I am wondering if there are any other concerns like hose pressure etc. I may be wrong but I understand the propane tank pressure can be as high as 250psi.

Originally Posted by 10Pups

I have been doing some research on building my own forge. Running straight from the tank sounds like a great money saving idea beside the fact that it works better. I am wondering about the safety factor in doing this. Like Charlie's valve is hooked up with a hose clamp. That kinda scares me. He is still around so I assume it has worked so far but I think I would use a little more secure fitting and I am wondering if there are any other concerns like hose pressure etc. I may be wrong but I understand the propane tank pressure can be as high as 250psi.

I have had the same thoughts, but have not acted on them. I do have a ball valve right at the tank so I can turn off quickly.

Charlie

You could mount a excess flow valve for extra safety!

Originally Posted by Lemur

You could mount a excess flow valve for extra safety!

That would help keep the ball of flame down to about a 25 ft. diameter and then it would taper down to about 6 ft' long at the end of a whipping hose. Well, that is the picture in my demented head. Nobody bends safety rules more than I do and I will say I have been very lucky in my life. I think I will try this direct tank hook up in my first design but I am going to go with this hose. >> Gas Regulator Replacement Hoses I have had a lot of equipment with various types of hoses and pressures and I will tell you that crossing apples with oranges in this case is not a good idea at all. If you run a petroleum product through a hose that is not rated for it the hose will slowly deteriorate from the inside and you won't see it coming. If you look at the pressure ratings on the 2 types of hose on that site you will get a better picture of what I am saying.
I did check on the tank pressure and it can be from 100 to 200 psi. Propane Regulator Facts , High pressure and low pressure propane , propane 101

And Charlie, I am keeping my fingers crossed for you !

I really like the forge, maybe you can make a youtube video on it. I think its great to come to this site and see all the writes up.