bound201

I couple of gas forge questions

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I'm reading the stickies and haven't come across these so I'll ask.

I'm looking at building a small gas forge out of a metal 5 gallon bucket due to my limited space right now. Most designs I have seen have 1 burner, I also read that there was an issue with welding with these as they didn't reliably hit a good temperature to weld with.

1.Can you add another burner but not light it unless you are wanting to weld?

2. The forge will be propane and I think most of the burners are running around 7-10 PSI on a 3/4 burner, how fast can you blow through say a normal grilling propane tank?

I've used coal in the past as I had tons of space and it was easier for me to get started with that in the past. Now I'm highly limited in space as I rent and don't want to take up too much space. I am a bit concerned about the cost of gas vs coal so this is the reason for question number 2.

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I found lots of info in the "stickies" on forges.
5 gal bucket seems a little large to me.
2nd burner becomes a chimney when not in use.
propane useage will depend on the size of the burner(s), size of the forge, how well insulated it is and how many hours a day its in use

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I saw one with a coffee can but that seemed too small.

I'm mainly curious about fuel usage, I know it depends on a lot but just mainly curious about fuel usage. I don't want to get something then blow through a small tank in 2 hours lol.

Yeah I thought the second burner would cause heat loss and the more I think about it the worse the idea sounds lol.

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I copied this from the Anvilfire Guru Page several years ago

EZ-Burner: Ricardo, That is an old Ron Reil plan hosted on his page. It has been built by thousands.

That burner is what is called an "Atmospheric Burner" because is runs on atmospheric pressure - there is no blower. They are used on many commercial forges.

They are very tricky to get everything balanced to run correctly. Any one burner will only work with one volume of forge. On commercial forges they add burners as the forge gets bigger. Make the forge twice as big and you need twice the number of burners. A single EZ-Burner will work on roughly a 1/3 of a cubic foot or about 10,000 cm3.

I quote from the Ron Reil site.
1. You will need at least 450 BTUs per cubic inch of forge chamber volume if your forge is going to be able to forge-weld. Some would argue for a figure as high as 540 BTUs per cubic inch.
2. The "Reil Burner" will deliver about 135,000 BTUs at medium to higher gas pressures, and can be cranked up to almost 200,000 BTUs by raising the pressure to 20 psi or more. In the lower pressure range of from 1-6 psi, where I do most of my work, it will produce about 60,000 BTUs, or even a little less. Use the middle figure in any design calculations.
3. Shoot for a burner to volume ratio of 1:300 or less. Some smiths who are very
knowledgeable would say a more conservative ratio of 1:250 would be safer and insure that your forge will be able to weld. To calculate how many 3/4" burners you will need just divide the total chamber volume of your forge, in cubic inches, by 250 or 300, and then round up. If you come out to a burner requirement of 2-1/3 burners, then you will need 3 burners for your planned forge volume. Always plan conservatively or you may end up with a forge that is too cold to forge-weld.

The above information is assuming that you will build a well insulated forge, having at least 2" of Kaowool lining coated with ITC-100, not Satinite, on the interior surface of the chamber. A 3" lining of Kaowool would be even better, and would probably pay for itself in fuel savings over the long run. If you elect to use a rammable or pourable refractory, or bricks, you will have to address the lower insulation values associated with these materials. One option is a composite design, a pourable refractory shell for durability, inside a Kaowool shell for insulation value. These are more difficult to build but are long lasting and can work very well.


EZ-Burner Numbers (more): Ricardo, I missed on the numbers for the Ron Reil burner (see how easy it is to screw up).

At his BTU value's (based on how much gas is used NOT how efficently it is burnt) the forge volume should:
• 60,000 BTU - 120 cuin (2000 cm3)
• 100,000BTU - 200 cuin (3300 cm3)
• 150,000BTU - 300 cuin (5000 cm3)
• 200,000BTU - 400 cuin (6500 cm3)

I have found that it is difficult to get one of these burners to run at that wide a range so the balance is more critical than it seems.

There is also a huge difference in the shape of pipe reduction bells. Some are a gently curving funnel (the right shape) and others are hemi-spherical and not a good shape for a venturi induction system.

Recently they have discovered that better designs of the same type burner with smooth induction bells, a good gas nozzle and a symetrical air damper (tubular) can operate at a much wider range.

Often the solution is simple. Close some of the forge off using a couple fire bricks, make the door opening smaller.

In all cases gas atmospheric forges take up to 45 minutes to get up to a good working heat and a couple hours for heavy refractory to abosorb enough heat that welding temperatures can be reached.

I hear these same problems from people over and over including folks with commercial gas forges. But there is almost never a failure using a blower type burner. If you have electricity to run one they are simplier to build and have a wider range of operation. The slightly higher presurization in the forge chambre assures a good high temperature for welding heats.

AND THAT brings up another point. If you are at high altitude your forge may not reach welding heat without a blower or preheating the

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