Domestic natural gas forges require a blower.
With propane you can get high pressure and can use that pressure to
draw air because of the high velocity at the orifice. This allows you
not use a blower. It means that for an equivalent volume of gas you
can use a smaller orifice with propane than you would with lower
pressure natural gas.
The trick with domestic natural gas is to keep the pipe feeding the
forge as large as possible for as long as possible. As you get close
to the forge you usually have no choice but to reduce pipe size. I
seem to recall that you can usually get 1" or 1 1/2" as your primary
feed and this can be reduced to 1/2" or 3/4" within the last foot or
two at the forge. Of course, you will have to reduce the pipe further
near the orifice but this should be a very short section.
I last looked into this about 3 years ago and I was working with the
idea of using 1/2 to 1 psi gas. This is normal domestic natural gas
pressure, or so I was told. I would think that 2psi would considerably
On Mon, 17 Nov 2003 07:10:25 -0800, Grant Erwin
Natural gas is normally deliverd at 5 water column inches. As a
comparison propane is delivered around 11 water column inches. 14
water column inches is 1/2 PSI.
Ironhorse, HSB#96, SENS BS
2001 Ultraclassic with Sidecar
96 Custom bucket of bolts (gone but not forgotten)
Plenty, but you'll need a blower. I run NG and forced air, and have no
problems with the pressure (just barely above atmospheric) that comes
out of the gas line from the meter. The idea is to choke down the inlet
to the blower so there will be a partial vacuum at the inlet, then just
open up the flow valve for the gas into the inlet opening. Mine has a
half-inch line going to the blower, centered over the inlet by a metal
spyder. The 'choke' plate rides on threads on the gas pipe, allowing
adjustment of the total air inlet area. When lighting, toss in some
kindling, turn on the blower, open the gas valve, WHOOOSH! fire. Air
first, then the fuel! Clear as mud, no?
The gas people in most locations react like that. I have access to 80 psi
natural gas on my property, but have opted for propane. It is more pleasant
to work around and is hotter. The rest of the guys have already told you how
to use 2 psi gas. It will do the job just fine, including forge welding, if
you do your homework and build an efficient forge. There are some very fine
natural gas forges out there.
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