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I Forge Iron

Testing with fire


mage2

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So thanks to all of you, I built a T burner based on frosty's design. is 3/4 ID black iron pipe 8" long with a .35 jet (mig tip). 

I have not built the body of the forge yet (need insulation and such) , so I decided to try it out with the body of one of my one brick forges. 

After drilling a hole and setting it all up I fired it up. I know the volume of the forge is way tiny  so there is some massive dragons breath but I just wanted to try it out. 

Anywho here is a picture. I think this was @ like 6psi. 

Its xxxxxxxx awesome. 

 

 

 

forgeBreath.jpg

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Make the tube 6" and put a thread protector or coupler on the outlet end. You're right though the back pressure firing into that small a chamber isn't going to let it breath so it's running WAY rich. You'll have better luck using a 1/2" in that small a volume.

I'll bet that baby would make 300 cu/in screaming HOT.

Frosty The Lucky.

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If you take Frosty's advice, you can back the burner up and aim the jet of flame threw the hole. This reduces the back presure and gives the fuel more time to burn befor hiting the back wall. Of corse as this is just to satisfy your inner  piro befor fitting it to a properly sized forge, its all good. 

I do belive Jerry gets a warm and fuzy feeling everytime he sees one of his children hatched and breathing fire.

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Yea this was just a "test run" I m sure its running crazy rich and there was some back pressure due to just the volume that I was pumping into that little space. It was expected. Didn't lose the hair off my fingers, so that was good.  I am just waiting for payday to get refractory and such. I am planning on using a used up single use helium tank mostly because I already have one. I dont know the dimensions off hand but I think about 2-3" of wool with the IR reflecting stuff coating it and  a hard fire brick that I am going to use for the floor. I think it will do well.  I will keep you all updated. 

 

 

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Okay, that's the second time this morning I've spent 20 minutes or more on a reply to have it forbidden. If this post goes through I'm saying post size is a large factor in Forbidding replies.  grrrr.:angry:

If this posts I'll make a couple short OT replies. Once I cool down that is. <sigh>

Frosty The Lucky.

wonder if its TIME to post,  rather than time alone...

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Yeah, I've started saving long posts to submit with the report if they're Forbidden. <evil grin>

On to the reply. Take those little forges apart and make on large one, you should be able to get about 140 cu/in. Open ended but near perfect for a 1/2" burner. Buy 4 more bricks and you've got chamber volume just right for the burner you have. A couple more to partially block the ends and you're golden.

If you really want a cylindrical forge, 2 ea. 1" layers of ceramic blanket is practical and plenty. It WILL degrade over time, no matter what you wash it with. Make the inside 1" (contact surface) sacrificial and easy to change out. It WILL wear out, make replacement easy on you. That is the single biggest criticism I have of most commercial propane forges, relining them is usually expensive and difficult.

Frosty The Lucky.

Edited by Frosty
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I don't really care about the shape of the forge, as much as the quality/usability. I honestly do not know why cylindrical forges are so popular, I just guessed they know something I don't.  These soft bricks are pretty old and abused. I have a dozen or so hard firebricks but I have no idea on the temps they are rated for. I could put them into making a forge, but from what I understood the wool gets hot faster than hard fire bricks(less mass?) I would like to be able to forge weld in this, is my end goal. would a hard fire brick forge do better at forge welding? You said this could make a hot 300 cubic inches. if i say went for around 200 cubic inches with hard fire brick, rectangular work area. Do you see any problems with forge welding once it gets up to temp?

I am sure this is covered somewhere, and i might have already read it and do not remember. So if i am asking something that's been beaten to death just drop me a link and tell me to RTFM. Ill read instead of you guys re-writing a novel.

comments?

 

Also when i do long posts, i copy them before i hit go, that way if the site has timed out my session i just paste it back in. 

 

 

 

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No there's nothing wrong with cylindrical forges, I've been wondering why so many guys put so much effort into them. S'okay, the only real effort is cutting the tank if you're using a tank for a shell. I like SS stove pipe for a cylindrical forge shell. Of course some folk put a lot of effort into almost everything.

The only time heavy fire brick is an advantage in a forge is if it's going to be running for long periods.

No, making a 300-350 cu/in capable burner run in a 200cu/in chamber won't make for a hotter fire, it'll  increase back pressure hurting efficiency OR if you leave one or both ends open make for 1/3 more dragon's breath. Neither is anything but wasted fuel and lower temps.

Last Saturday I demoed in a brick pile forge using 3,000f heavy firebrick and the burner from my forge that melts the fire brick floor under it. It took better than 2 hrs to come up to good forging temp and never reached easy welding temps. This is the hard brick soaking up many MANY more BTUs warming up and wasting many more because it's about an r-1 insulation. So, no using hard brick isn't a good idea unless you have unlimited free propane or are going to keep the thing running for a couple days straight.

Frosty The Lucky.

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Charles, I didn't lose the hair on my knuckles because I am at least partly fire resistant.

Frosty. Thanks for the info. so building out of softbrick is better, and wool is better than that?

What is best to use for the floor of the forge? I have read many tutorials and blogs on forge builds. Its sometimes hard to separate the wheat from the chaff. 

My initial plan was a cyl forge with walls roof with 2-3 inches of coated inswool  and a hard brick for the floor. I worry that the brick on the floor might give me problem if it soaks up all my BTU. What about softbrick for floor?

 

 

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A cylindrical forge is good. More than 2" of ceramic wool isn't enough gain to be worth it. Kiln wash the contact layer, that's fire contact. If you aim your burners so they are tangential it/they will form a vortex in the chamber and make for more even forge temperature.

Don't worry about the "best" you get to spend years trying stuff, just let us know if you find something really good.

I have split 3,000f hard fire bricks for my floor. They're sacrificial, flux dissolves them and my one golden bullet burner melts them. I change them out when they get too degraded.

Kiln shelf is popular, it's thin and high temperature. Flux is going to eat it anyway, sometimes fast sometimes not so fast. It's a sacrificial floor and will benefit from kiln wash.

I don't know how many if any folk are still making stainless steel pans to keep flux off their forge floors but that was popular a while back. I don't know about now.

Frosty The Lucky.

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I do not have the exact dimensions of the tank, I have the tank just no tape measure..

kidding.. nah I just have not unearthed it from the closet of junk. So based on my google skills with 2 layers of wool I am looking at 520ish cubic inches(cant remember exact number) so once I get it out and measure it ill know exactly how much wool to use to get it closer to that 300ish area. No body never said more insulation would hurt things..

 

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Charles is right, you can shorten the cylinder and reduce the volume. This can be preferable on two counts. First being you just don't want to heat so much length, you can't work it. Second being heat. A single burner in a long forge will make one hot spot with lowering temps as you move away from it.

Frosty The Lucky.

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