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Haasum

Burner Location

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Hey everyone. I'm about ready to put my forge together but while I was looking at it I got to wondering about placement.

Should the burner be angled from one of the top 90 degree corners. Or should it be straight down over where the metal will sit? Or straight in from the side? With a round forge I always see them angled at about 45 degrees but that proves more difficult on a box like I will be using.

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For those concerned about toxic vapors from paint on the crate I have asked and tried to do as much research as I can and most of the guys I work with don't think it will be toxic, however the forge will be in open air anyway so it shouldn't be too big of a deal. It is an ammo can that held 25 mm rounds originally. That being said I have still considered removing the paint.

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Haasum: This is the first time I've notice you're on Kodiak! Or have we talked about the rock and other smiths in your neighborhood before and it just slipped my mind, what's left that is.

 

Burner orientation has a lot to do with what you want your forge to do for you. Typical orientation is straight down from the top and there are advantages. This gives you a hot spot and cooler areas the farther you move your work from the SPOT.

 

You can get a similar situation placing the so it fires from the side. If the orientation is more or less centered on the far wall you'll have a forge with a hot zone and cooler zones. There are advantages to this as it'll give you the ability to heat a smaller area of your work. It isn't going to be as differentiated as a coal or charcoal forge can provide but it's about what you can get from a gasser.

 

If you're looking to heat treat blades then a good vortex will distribute the heat more evenly. So, orienting the burner so the flame impacts at an angle to form a vortex is a good thing. A lot of guys do this by orienting the burner so it burns parallel with the top of the forge chamber. This pretty well removes a HOT spot while evenly distributing the heat over the entire forge chamber.

 

If you orient the burner so it burns across the forge floor you get pretty even heat distribution but still have a screamingly HOT zone. If that's what you're after of course.

 

If you want to orient the burner at an angle to achieve a vortex do NOT aim it at the far corner, this can cause excessive back pressure to the burner and cause poor performance. This will really effect a naturally aspirated (atmospheric) burner but will effect a gun (blown) burner too.

 

The best way I know of for a person to decide what works best for them is to construct brick pile forges and experiment with burner orientation till you get what works for you. And the "What Works For YOU" effect is what makes blacksmithing an art. everybody is different so different things work best for the individual.

 

Enjoy the journey,

 
Frosty The Lucky. In Wasilla.
 
P.S. We've moved the Alaska club site to IFI so you can keep up and yak at guys who know what a Sucker hole is. know the difference between Larson Bay and Anton Larson Bay. If you're thinking of visiting South Central to do some shopping maybe, Gordon Williams is planning a pedal powered bike trip and doing some clinics.

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Well I'm just starting out so ill have to experiment a little I suppose.

I don't recall if we have talked about my being on the rock or not. I'm in the coast guard and spend a lot of time at sea. I've been here for just over two years now and have about a year actually on the ocean when I add up all the days spent underway. I won't be visiting mainland Alaska for quite some time as I have leave and back underway coming up.

I recently did some math on my box and its a bit too large for one burner, so I'm probably going to have way more insulation than I need in order to get it down to a smaller size. I'm just starting so I don't mind waiting a little longer for my metal to heat up and I don't really need forge welding temps right away. But as it is with the double layer of insulation the forge would be 672 cubic inches which is well into the two burner size. I'll probably try it as is and then I can always adjust it later!

Thanks for the reply Frosty.

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Unless you have already built it, I suggest you build a smaller forge, especially if this is your first one.  I do most of my forging from a burn chamber of about 160 cubic inches, which is made from 9 inches of an 8.5" OD cylinder with soft brick for doors (2" of thermal blanket for insulation and a refractory floor).  You will save fuel and will be up to forging temperatures much faster.   

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Well I have a smaller ammo can I can use. Maybe I'll make that one a forge and save my large one for another day.

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For this design forge, and general forging, I'd put it straight up and down.  It will provide less stress to the box (which can distort as it gets hot) and the hot spot on the floor is very, very useful. 

 

Different answer if you're doing heat treating.

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Okay so I went with a smaller ammo can in order to save fuel mainly. So here's what I have.

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However I got to thinking, this ammo can has a rubber seal to make it water tight. Should I pop out that seal or should it stay cool enough to not melt or combust? Right now I'm leaning toward taking it out just to be safe.

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Putting my burner together tomorrow then I just need a way to secure it to the forge, probably part if a pipe with set screws.

Sorry for the awkwardly angled pics I'm on duty and don't have a way to change my picture orientation.

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1) Yes, remove the seal.

 

2) Use a floor flange to hold a pipe nipple.  Drill and tap the pipe nipple to hold 1/4"-20 pitch bolts - use these to grab the burner.  Bolt the floor flange to the top of your ammo can.

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Thanks for your service, the coast guard holds a special place in Alaskan's hearts.

 

Yeah, if you replace the rubber gasket with stove rope gasket it'll seal better, the loose lid would be a pain.

 

Did you consider laying the can on it's side and placing the burner in the side facing up? That's give you a full length door and a solid burner mount. With the shape I'd think about putting the burner at the end top or bottom of the chamber or back pressure would disrupt it.

 

Don't sweat warpage, 2" of Kaowool will keep it from getting hot enough to singe the paint let alone warp it. My old forge has 2" of Kaowool and you can touch the shell with bare skin, briefly sure but it's only hot to the touch, like a fresh cup of coffee.

 

A well adjusted 3/4" naturally aspirated burner will bring 300-350 cu/in to welding temp very reliably, especially with good insulation and a restricted door.

 

Oh yeah, I almost forgot. I just weld a sheet steel "washer" shaped object to my burners and let them sit on top of my forge. The copper fuel lines and the way the thread protectors I use instead of flares fit in the kaowool holds the burners well enough. It's not like you're going to be rough housing a running forge, that's be a B-A-D thing, a mucho ungoodness thing.

 

It's looking good, you're on the right track, no worries. These things aren't rocket science. (Well we HOPE they aren't rockets! :O) It may need some tuning to get it right but we're here and happy to give advice, even if we have to make things up. <grin>

 

Frosty The Lucky.

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