# Foundry: How to Build a Burner (Natural Gas)

I'm fairly new to the whole casting bit, just got my foundry up and running a month ago. It took me about six months to figure out how to build a natural gas burner, do to the lack of instruction on the web, so I figured I'd throw in my two cents and show how I made mine.

What I'm posting is what I've learned through trial and error. If anyone has more information or ideas I'd appreciate it if you would let me know.

That being said, I'm not responsible for the actions or ideas of anyone that reads this. There is always a risk when working on "diy" projects, especially those that involve fire. Please practice safety when engaging in any type of casting or metal work.

## Step 1: Background

Just a bit of background to explain why I made the burner the way I did.

First off I'm a college student, (i.e. broke) I had to use what was readily available to me, so propane was out of the question.

The natural gas line that I had access to was only 5 psi @ 3/4", so I needed a forced air system.

I had bought the foundry (minus the burner) from a blacksmith shop I go to on the weekends, so the inlet diameter on mine was preset at 1.5" with a 1" hole going into the brick work. It's inside diameter is 10" with a 12" depth. The crucible I have is an A10 (7 5/16" inside height, 5 11/16" inside top, and 3 3/4" inside bottom; holds about 1.5 L)
jncunningham1 year ago

For the gas inlet, what's the the reason for having the end cap with the 1/8" hole? I get that it will increase the exit velocity of the gas and probably help mixing; but wouldn't it mix well enough if you just attached the valve directly to the mixing chamber?

jedi_knt (author)  jncunningham1 year ago
In a word, "blowback". the pressure caused by the 2"-1" reduction can overpower the PSI of the gas inlet if the hole were any bigger. for this reason alone, I highly recommend an anti - blowback valve, it is designed to stop air tracing itself back through the gas line. I would also recommend taking a look at my V2 instructable, it is more streamlined and more efficient. Natural Gas Burner V2.
1 year ago
Got it, makes sense. Thanks!
EshKuno2 years ago
Pretty cool, a diy power burner. While 5psi doesn't sound impressive, it's dangerous in the hands of a weekend warrior. Most people don't have access to this type of pressure. The pressure in most homes is about 1/3psi. Are you running 5psi thru this bad boy? Not to rain on your parade, it just seems crazy to me. I've seen 1,000,000 BTU boilers running on under 1psi!
jedi_knt (author)  EshKuno2 years ago
The place that I'm at is a bit older so 5 psi may have been a standard when it was built, but I have no way of knowing that for sure. Also with a quick bit of research, it looks like average NG psi seems to very by region...

Most of the time, when using the burner, I have the control valve about half open; otherwise the flame is blown out by the fan. If I had to do it again I would probably go for one that only went up to 100 CFM.

If you have access to the plans for the 1,000,000 BTU burner please share; I'd be interested in seeing how they are built.
2 years ago
Delivery pressure varies from by region, true, even by city. All houses, buildings, etc have step down regulation which reduce the pressure typically to 1/3PSI. gas appliances also have a step down regulator which usually reduces the pressure to 1/6PSI.

Chances are, you probably are only getting 1/3PSI. At the main shut off for your house there should be a regulator. It should say how much pressure its delivering.

Don't have any plans for any 1,000,000 BTU burner.
curvy773 years ago
this is very intresting. im not gonna use this (no offense) cause i prefer more athentic means but the design is quite functinal. what are you using for crucible?
jedi_knt (author)  curvy773 years ago
Ceramic graphite I believe, i have a few of them lying around.

My brother and I have recently made a few tweeks (I havent posted it yet) that really beefed up the burner It will get the foundry hot enough to start meltin in 15min.
2 years ago
jedi, could you give an explanation of the tweaks you made ? This would be very usefull. Thankyou.
jedi_knt (author)  cfreitas2 years ago
Ok so when I said we made a few tweaks we almost nearly redesigned the whole thing; for the better I might add. cheaper with less parts and more efficient. I meant to go back and update, but I got carried away with other things.

http://imgur.com/a/6kz5f#0

We replaced the T section with a 2"x8" nipple and welded a 1/2" black pipe to it. a 90 degree sits at the end of the of the black pipe in the middle of the 2" nipple the 90 is attached to an black nipple terminating at a 1/2"-1/4" reducer (the brass tip).

Depending on your need (forge/foundry) the nossel for the outer pipe can be changed out. I have to collect some pics to make a new tutorial. I'll get on it this week end.
2 years ago
I gave some steps ahead and bought a Jacuzzi water cilinder from a deposit of scrap and it costed me only 4 US\$ :) Its big enough to make a nice furnace. Already took it to a machinist here and asked him to make cuts and holes on it, and also to place iron bars down on it to make it moveable something like yours. Unhappily I dont have all the tools needed to it ( yet ) so I thought would be better to get some things made for someone more experienced then I.

I´m very concerned about the gas thing, hope I can get it to work at least reasonably with Butane gas.

I saw your pictures in imgur.com and I will be waiting for any news that you post.

And thanks again.
jedi_knt (author)  cfreitas2 years ago
since it sounds like your still gearing up you might want to look at this...

http://www.gasapplianceco.com/pdf/venturi_spec.pdf
http://shop.clay-planet.com/mr-750-venturi-burner.aspx

I just found out about them today, kinda wish i knew about it when I first started.

best of luck
2 years ago
Yes, I see.
Its a little expensive to me this burner. I think I will try to keep it as cheap as possible. Will you still publish your changes here ?
jedi_knt (author)  cfreitas2 years ago
I'll probably wright up a new one based on the amount of changes we made
cfreitas2 years ago
Hi there. I like a lot your instructable, and like more the clean aspect of the result.
I suppose the natural gas you use is Butane, not propane, right ?
I only have access to Butane ( the one used in kitchens ) in tanks, so I think I could give this setup a try.
I just need to know if yes, this is butane gas.

Congrats, nice work.
jedi_knt (author)  cfreitas2 years ago
Sorry for the late reply...Butane is the fuel source I designed this thing to work off of a 5 psi gas line, the one originally used for the barbeque.

The first fan I got was a little too powerful at 150 cfm though it will produce a good 18" long flame it occasionally blows out the flame; but I think that has to do more with the nossel size vs the foundry inlet than the fan. You might be better off with a fan some where in the ballpark of 100 cfm.
mcee23 years ago
This is a great step by step blog on how to make a burner. I had a little trouble with the plumbers tape, but got it figured out. Thanks a lot for the help.