Stabber found out A little more info for you. You would have to have a 15 lb seperate regulator on your meter. They offer up to 25lb .Natural gas runs about half the BTU that propane, so your orfice would be closer to number 37 to 38 depending on the size of your forge. You will need a forced air set up, my friends is 110 cfm but he recomended 150 would be better to push more volume. Here is a cost comparson Let's assume the cost for natural gas is $15.00 per 1,000 cubic feet. This means that $15.00 will purchase approximately 1.03 million BTU's of energy. This would be equivalent to 11.26 gallons of propane. At $2.50 per gallon of propane, natural gas would be a more cost effective . Breaking it down even further, natural gas needs to be more than $28.00 per 1,000 cubic feet for propane to be a more cost effective energy solution (provided the cost for propane is $2.50 per gallon. Now that being said if you are looking for forgewelding temperatures its a little tough to get to, but forging temperatures easy. Like any thing there are pros and cons