Anyone using natural gas for their forge

[djberta]

My propane metal melting forge fournace was damaged when we moved and I was thinking of building a new one. Instead of propane using natural gas?

 

[David]

Based on my extensive BBQ experience propane is hotter than natural gas so I would think you may have to upsize the burner orifice maybe?

 

[jcdammeyer]

I'm using nat gas now. And @David is correct. You have to change the jet size. I can't find the files or information on what I did.
One thing to keep in mind, in the old days the gas pressure after the house meter/regulator was pretty low. Now it's around 2 or 3 PSI and BBQs use about 0.7 PSI. The propane foundries tend to run at least 10-15 PSI IIRC. BBQs drop the pressure down to 0.7 PSI again IIRC.

 

[phaxtris]

The burn temperature of natural gas and propane is very close, like withen 100f, i think the low pressure is why you would need that larger jet

edit ; found it, the btu content is considerably lower in natural gas that's the reason it seems "colder", 2500btu per cu/ft of propane, 1050btu per cu/ft of natural gas, so you are going to burn 2.5x the natural gas to get the same energy output as propane, probably still considerably cheaper though

 

[jcdammeyer]

The burn temperature of natural gas and propane is very close, like withen 100f, i think the low pressure is why you would need that larger jet

edit ; found it, the btu content is considerably lower in natural gas that's the reason it seems "colder", 2500btu per cu/ft of propane, 1050btu per cu/ft of natural gas, so you are going to burn 2.5x the natural gas to get the same energy output as propane, probably still considerably cheaper though

Yes. Back when I was using Propane each melt into my #6 crucible used about 1.5 lbs of propane and once the 20# bottle was more than half empty the pressure dropped enough that a refill was needed. I think each melt was costing me about $2.

With the Nat Gas I barely notice it on my bill because of all the extraneous costs like transportation etc.

 

[phaxtris]

Im sure its worth it to not have to fill a bottle all the time either, just dont forget to turn it off!

 

[jcdammeyer]

Im sure its worth it to not have to fill a bottle all the time either, just dont forget to turn it off!

I have, as expected since I'm rather anal, a computer module running my furnace. Spark Plug Ignition and project 42 was to install the flame detector which is still sitting in the box.

To light the furnace the lid is opened. Master ball valve on wall turned on. Valve on furnace turned to on. Then Start button pressed. Fan starts up at slow speed. Spark starts. Solenoid clicks open and furnace goes woosh as the gas lights. Orange/Yellow flames billowing out the top. Fan then ramps up to full speed, flame withdraws and becomes nice blue aimed at the bottom side of the crucible. Spark has stopped after flame started.
Switching off cuts gas, flame goes out, fan cycles down to low speed for a few seconds and then off. There is a switch setting for low speed continuous to slowly cool the furnace and heat the shop.

There is no gas regulator so pressure is about 2 or 3 PSI. Hence a fan is mandatory to get decent flame and heat.

 

[phaxtris]

sounds high tech

have you or anyone else here built a waste oil burner ? a foundry furnace has been a back burner idea for a long while, and i always have a pile of used motor oil....

 

[David]

Mark Presling built a diesel fired forge.

Diesel Furnace Burner For Your Foundry

A DIY diesel fuelled furnace burner and service cart that doesn't require any compressed air. The design was based on a version I saw on SWDWEEB's channel. T...

youtube.com

 

[Tom O]

Here’s a chart for you

 

[djberta]

The biggest reason to go nat gas for me is to not have to keep getting propane. I don't think I would be building an automatic system any time soon. Although I do have an ignitor here for another project. Could a water tank or heater gas valve be used? I have seen the waste oil ones and talked to one of the ytubers back several years ago and he said it can be a mess. But it smells like you cooking fries all the time.

 

[phaxtris]

The biggest reason to go nat gas for me is to not have to keep getting propane. I don't think I would be building an automatic system any time soon. Although I do have an ignitor here for another project. Could a water tank or heater gas valve be used? I have seen the waste oil ones and talked to one of the ytubers back several years ago and he said it can be a mess. But it smells like you cooking fries all the time.

I dont know if either of those valves would flow enough, but they are reliable, assuming you didn't melt the thermocouple, you could potentially mount it in the burner tube off to the side so that it didnt get overly hot

I was thinking more waste engine oil, but the smell and smoke had concerned me, the neighbors may not take kindly to it if it smokes out the whole backlane, i might have to experiment, see how cleanly it burns

 

[Dan Dubeau]

Just start it on waste veggie oil so they get a whiff of french fries, get the munchies, then run out for McD's. When they're gone, switch over to the used motor oil.

 

[BldrJ]

I’m running natural gas, naturally aspirated, melting bronze.

 

[Proxule]

I’m running natural gas, naturally aspirated, melting bronze.

Can you show us your setup, details, etc etc?
Thanks!

 

[PaulL]

The biggest reason to go nat gas for me is to not have to keep getting propane

The more important reason is to not worry about bottle freeze.
20lbs bottles freeze up too fast when forge welding. The 100lbs ones are better, but the last 20-30lbs freeze up the same way. You won't have that problem with municipal gas service.

Though these days I'm using my induction forge much more often than the gas.

 

[Gippeto]

sounds high tech

have you or anyone else here built a waste oil burner ? a foundry furnace has been a back burner idea for a long while, and i always have a pile of used motor oil....

Technically, yes put together a siphon nozzle setup. Run it on kero or diesel for the most part. Total overkill for aluminum. Also have a Moya style drip burner which has a propane inlet for preheat...usually just use it as forced air/propane for aluminum.