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bw94

Trying to build a gas forge

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I've been trying to find instructions on building one

A Book  Gas burners for Forges, Furnaces & Kilns by Michael Porter   Sold by Skipjack Press.  is one good place to start.  Another good place is to search this forum for Frosty T 

 

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A Book  Gas burners for Forges, Furnaces & Kilns by Michael Porter   Sold by Skipjack Press.  is one good place to start.  Another good place is to search this forum for Frosty T 

 

I've purchased this book, frostys t burner look like a lot simpler design

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They are both workable designs.   Frosty's  design is simpler. More complicated means more flexible tune adjustments, but simpler means fewer errors in installation. Both are good.

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Sorry I'm late replying, I'm running amazingly short of time for a retired guy. I'm still editing my T build directions, I'm a naturally wordy guy and have been doing a lot of cutting to make it reasonable size and still cover the bases.

No chokes on the T under normal conditions though some guys need more control of the atmosphere. Properly tuned a naturally aspirated burner's fuel air ratio is an almost flat curve at different gas pressures. Part of the reason I was messing with my burners recently was to make altering the ratio easier, that turned out to be more trouble than it's worth.

The gas jet sizes are different according to tube size but I'm not good enough at mathematics to develop a formula. What I did was experiment till I got good jet sizes for the burner sizes I've made. They are as follows.

1" burner = 0.045" mig tip.

3/4" burner = 0.035" mig tip

1/2" burner = 0.023" mig tip.

The above jet sizes work well enough but may need adjustment. I tune my burners by trimming the mig contact tip length, the farther the tip is set back from the beginning to the burner tube the more air it entrains and the leaner the ratio. As you can see from pictures of other burner builds the set back can be very different but you'll also notice they are using a different air intake port design. The Porter design vs. Ron Reil's EZ, vs. Mike Hammer's design, vs. a T, vs. Side arm, vs. whatever someone comes up with. They all work and once you understand the basic mechanics you can make a surprising number of configurations produce a flame to your specs.

Frosty The Lucky.

 

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With the side arm burner it is important to use a tapered tip.  I had a student that had built a forge and his burner and it would not burn well.  He had a common 1.5 X1.5X.75 T.  I got him to get a Ward T (commonly used in sprinkler systems) .  That helped but it still did not burn well.  He was using a standard mig tip.  I got him to get a Tweco T tip (t = tapered) and then everything worked well.  Sometimes it can be very important to follow instructions closely.

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Thanks frosty, so would I use a 1/2x1/2x1/2 tee if I was making a 1/2 t burner, what length would the pipe need to be?

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Thanks frosty, so would I use a 1/2x1/2x1/2 tee if I was making a 1/2 t burner, what length would the pipe need to be?

No. You use a 3/4" x 1/2" T. The first number is the "run" the second is the "chase". In plumbing terms the run is the "line" or "supply" pipe. (the cross arms on the letter T) The chase is the line branching off the main supply line or "run," sometimes called a "drop."

To make the air intakes breath easy you want them a little larger than the burner tube. I've made burners with the same size intakes as tube but had to use a smaller gas jet to get a neutral burn. Using larger air intakes lets me use a larger gas jet so it puts more fuel and air in the forge for more heat.

Following the formula a 1/2" T burner needs: 1/2"x4" black iron nipple, a 3/4"x1/2" black iron T, brass fittings, drills, taps, etc. as usual and a 0.023" mig contact tip.

Do NOT confuse the T with a Side Arm, they're the same in principle but two different builds, the ratios I use in a T will NOT work in a Side Arm. Think of it like using the right spark plugs in your car.

Frosty The Lucky.

 

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We'll I started making the burners and I have a question about the length of the down tube, frosty says a 8"-9" works well for the 3/4 burner, I've seen pictures of others that are shorter and seem to work well, my question is what would be a good overall length for the down tube? And would I have to use a flare on the end of it? Thanks alot

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What about the 3/4 t burner 

The ratio to figure it out is tube diameter x 8. 3/4 x 8 = 6

Frosty The Lucky.

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Ok, thanks I must have misread or this is a different burner, on the 6" nipple do u leave the threads on or cut down to 6"? And on the mig tips, are they tapered tweeco?

image.jpg

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Alright, here's my plan. I plan on cutting down the forge from 18" length to 14" and adding a 4" pass thru hole in the back of the forge for longer material. I figured out with the 2" of blanket it would take it to 6"x10, that should put me at around 300 cu", not sure if I'm gonna use 1/2" t burner or a 3/4" t burner.

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If you're making a 3/4" burner 6"-7" is fine, threads on the output end don't matter.

A 6"x10", 300cu/in forge is in the range a 3/4" burner will heat nicely. TWO 1/2" burners are roughly the same BTU output and you can space them so the chamber is more evenly heated.

Frosty The Lucky.

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Do u think it would be ok to run 2 3/4 t burners and run them at a lower psi,  or should I run 2 1/2 T burners?

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Do u think it would be ok to run 2 3/4 t burners and run them at a lower psi,  or should I run 2 1/2 T burners?

Why do you want to experiment with mature technology? Blacksmiths have been building and using these things since gas lights lit streets in cities 120+ years ago. U Rnt going to figure out something good unless U nu enough U wouldn't need to ask the question.

Just follow the directions and do what works for everybody else. I'm a curmugeonly old fart please write like you passed an English class if you want my help.

Frosty The Lucky.

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Your right Frosty, there's no need in experimenting with a proven design, I'm gonna stick with two 1/2" T burners. Sorry for the abbreviations and lack of knowledge. This is my first attempt at building a gas forge, I just want to get it right. Thanks

Edited by bw94

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Your right Frosty, there's no need in experimenting with a proven design, I'm gonna stick with two 1/2" T burners. Sorry for the abbreviations and lack of knowledge. This is my first attempt at building a gas forge, I just want to get it right. Thanks

S'okay, I was in a mood is all. It's a curmudgeon thing. 

Never apologize for a lack of knowledge, admitting it is a  positive personality trait. Wanting to get things right is a good thing too. I hang here to spread some of what I've learned around. I spread bad jokes and long rambly missives too but I try to make up for it.

If an apology is due it's mine, there was no need to take out my aggravation on you, I don't even know what's on my nerves sometimes. I'm glad to be of what help I can. Give me a shout, I'll get back.

Frosty The Lucky.

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That's well out of my grasp Wayne. I don't know who could fill his shoes.

Frosty The Lucky.

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Frosty I personally think your doing a great job spreading your knowledge, and seeing as you have answered that very same question to me in the last week it must get old being asked the same old questions everyday. I guess what I am seeing on IFI is all newbies think alike(darn it I like to be different). If a 10" pipe makes a good forge than 36" has gotta be way cooler.....I'm gonna improve upon the simple burner and make it better....(even tho I have never made one before) if 9" is a good length than 24" must be way better......and the killer thought.....I watched a 1 hour tv show a few times, I know as much as these idiots that have been doing it for 10, 20,30 years 

I guess what I want to say is, Thank You Frosty and also wayne, thor, and and everyone else that share your hard earned knowledge with us newbies I for one really appreciate it.

Edited by cranky

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What most people today forget is that this tech has been noodled over and modified by far greater minds than their own for a millennia. (Maybe not the gas forge part, but still)

Men who had the forethought to imagine it could be done and do it even though many around them said it was impossible. Theses men forged (pun intended) the way for us numbskulls to come along and think that we can improve upon it.

Every now and then someone can have a spark of genius and come up with something that works, or works better. but for the most part, What we are trying to learn/modify has already reached it's peak. And really the only thing left to improve upon is ones own skills and technique.

Sure a new tool can come along that can be adapted to be used with Black smithing. Power hammers, pneumatics, gas forges all come to mind. but in the end, the one in charge of the hammer is the real factor that matters.

Sure a more efficient forge will heat a piece of metal faster, but it can't turn it into something beautiful. An anvil and hammer can change the shape of the metal, but it cannot make it functional. There are thousands of Blacksmiths who have made far more beautiful things than you or I, but they have had a fraction of the technology and far harder tools to use than you or I.

 

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