Rob, I have one of the NC Tool company three burner forges. Running at four pounds it takes fifteen minutes or so to reach welding temp. I normally forge at one pound of pressure, four to five for welding.

Brion

Thanks Brion

I think my single burner ain't quite cuttin it !

My cast refractory, single forced air burner forge takes about 20 minutes to get to welding heat.

Steve,

What psi do you use?

Thanks,

Bob

What psi do you use?

LOL! I don't know. I run my forge off a high pressure line from the 500 gal tank that supplies our house and my shop. The high pressure line is around 10psi. I don't have a gauge on it. I control the forge with the ball valve on the blower assembly. I have to close the ball valve WAY down.

I've run this forge off a 100lb tank at the Heartland Symposium. Never been very careful with the setting of the pressure. Always count on the ball valve for control.

Once my forge runs long enough to heat soak the cast refractory (maybe an hour), I can turn the air blast and gas down to next to nothing and it will stay at welding heat all day.

|quoted:

My cast refractory, single forced air burner forge takes about 20 minutes to get to welding heat.

thanks Steve....mine isn't forced air , that may be the issue I'm thinking........

Thanks Steve,

Mine is also running off the 500 gal tank that feeds the house. I installed a gauge though. Guess maybe I need to just crank it all the way up to 10 psi, and use the ball valve more to regulate things. I've been trying to use both.

Bob

I'm running off a 200 gallon tank. I use a regulator with a gauge and weld at 5 lbs. I fine tune it with a needle valve and have a ball valve to adjust the air.

Dale

Mine is also running off the 500 gal tank that feeds the house. I installed a gauge though. Guess maybe I need to just crank it all the way up to 10 psi, and use the ball valve more to regulate things

Just a point to make here... Not all lines from large propane tanks have a 10psi line. It depends on your propane supplier's set-up. Some tanks have a regulator on the tank that drops the pressure to whatever it is that a furnace requires. This is too little pressure to run most propane forges. In a set-up like my propane supplier installed, there is a regulator on the tank that drops the pressure to 10psi. The 10psi line runs to the building and another regulator is installed at the building to drop the pressure to household use pressure.

I tied into the 10psi line without asking my propane supplier if it was okay with him. <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//tongue.gi f' class='bbc_emoticon' alt=':P' /> Not sure that he wouldn't throw a fit if he knew. Also doubt that this is something that would be acceptable anywhere there are building codes. I live in the country, were there are few building codes and safety requirements. Depending where you live, this may not be a good idea!!!

The gas company ran my line for $50. I asked him what the pressure was going to the shop, and it was 10 psi. It steps down at the regulator going into the house. Next forging session I'll give it a try the way you posted above.

Thanks for the Info!

Bob

These days, most residential propane suppliers will not allow more then 10psi going into any structure. That being said, if you get to know the folks who supply your propane, and show them you know what you're doing, they are often understanding. For example, when I built my new "hot" shop several years ago, I ran all the lines myself, and all the propane folks did was pressure test my lines, then installed the 500 gal tank. At that time 10psi was the limit......but when I added additional forges to the shop, I needed more psi, and they provided me with all the fittings, and an adjustable regulator...now I have 20+ psi running into the hot shop.

Back the origonal question..... my welding forge is a vertical design, single burner, with a blower, and 1", #8 density kawool with ITC coating..... it runs a 6psi, and takes about 10 mins to reach 2350F. Once there, I can back off the pressure to about 4psi and weld all day in it.

I'm not a fan of venturi burners for welding applications.....those that do achieve welding temp simply take too long to get there, and use WAY too much fuel.

I think that forge and burner design will be more of a factor than pressure. When I was running a horizontal with a venturi burner I had to crank it up to around 20+psi to get to welding heat. Now in a blown vertical the pressure is much less (no gauge on this one).

That said pressure isn't necessarily an indicator of how much gas is used. Though my old forge was running at higher pressures, the gas was being forced through a tiny jet. With the blown it is coming in on a 1/4" line, so it isn't ever going to get above a few psi.

That said, my current forge is at welding heat in 20min or so and my horizontal was about the same. I think the key is good insulation with itc-100, and a decent burner. I am also a fan of the vertical forge (more even heat), and though I'm happy with the blown burner I'd still like to try out the t-rex venturi.

What kind of burner are you running and how is your forge insulated.

Dale, That's exactly the way I do it, except I don't have the ball valve for more air control. Been thinking about adding one after reading the other thread awhile back about forges. I have the smaller Kayne and Son's blower, and have to just about choke it all the way down. A ball valve will help for sure!

Bob

Just to add to the mix. I run my forge at 5lbs for everything and as Steve describes I control the balance of forced air to propane in a two jet forge to get to weld heat. That takes about 20 minutes for a larger than average sized internal forge volume. Remember that there is a heat to volume ratio. Too large a forge volume and you can have problems getting it to welding heat and that includes how long it takes to get there. Also, I am assuming you adjust the mix of air and propane to get the best heat. In my forge I can have weld heat at 4lbs psi or I can have weld heat at 8lbs psi. If not adjusted for the balance of gas and air (oxygen)I cannot get weld heat at either. In my set up having just a slightly rich (gas to air) ration gives me the best heat at weld temperatures. I stick with 5lbs psi and it seems to work. Temperature and humidity on any given day seems to require a slight adjustment to get the best heat.

Dan