Anyone using a natural gas forge?

[Michel Dupuis]

I will be building my first gas forge using David Robertson's Gas Forge Construction manual as a guide. It will use propane as a fuel source. Is anyone using natural gas instead of propane?

[dablacksmith]

i do a fair in puyallup every year and we use natural gas there ... the problem is you need a acumulator to increase the pressure from what the normal pressure is . its possable to do but its not cheap and you need to talk to your gas company to get it installed . once you have enuf pressure it works about the same .

[SoCal Dave]

Each forge requires a different minimum amount of natural gas pressure measured in lbs of water column. You have to check with your natural gas company on the amount to your meter and know how much your forge will require. . The one issue is adjusting the pressure to the forge when you need a lot of gas for some big items to heat. The manufacturer of your forge should know the minimum amount required.

[dkaschner]

The primary issues when using any gas in a forge is supplying enough BTUs to the forge. This is very doable with natural gas if you are aware of adjust for two variables.

1. Typically natural gas is supplied at a lower pressure to a residence than you are used to using with propane.
2. Natuaral gas has a lower thermal content than propane, i.e., less BTUs per unit volume.

Adjustments:

1. Use a bigger line. You may have to use a 1/2" or larger line instead of the 1/4" line used with propane. I weld with my natural gas forge at less than 2 psi (my house is supplied with 2 psi service as opposed to 11" wc).

2. If you are not using a blown forge, I would suggest swtiching to it. Venturi forges use the pressure as an aid in the mixing chamber. You don't have that luxury at 11" wc (less than 1 psi), so the blower is used to provide the pressure for mixing the air and fuel.

It is definately doable, although it may require some retooling.

Dan Kaschner