forge disign delima

Hi all. I built a forge burner for a fellow blacksmith eurler this year. I use the reil ez-burner disign. I have built quiet a few of these burners
over the years with no problmes. My frend is trying to build a stacked brick type forge so he can heat just the tip of the metal in the forge. He is in to making flowers. to the problim. he has instaled the burner in his small forge and cano't get the burner to produce enought heat to work the metal. he is used to using a forced air system in his forges so he feals that the smaller the forge chambr the easer to heet. I conted that with a naturaly asperated burner like the ez-burner that if the forge body is to small say the valume of one fire brick that there is not enough room to hold enough air to mix with the valume of propane injected into the forge body to burn properly. He stated that he gets alot of dragon's breath out of the forge entrance.
my thought is no air no combustion. Or not enought air not enought combustion. If any one out there has run into this problim I would like to here from you.
thaks all. snipped-for-privacy@cybertrails.com
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Vent? :)
Somehow I wonder if that's the problem... since you've built quite a few... you'd know that?

In theory the right amount of air is being drawn in by the burner itself, automatically so... no, it doesn't need a big box.
Alvin in AZ
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My own experience with the naturally aspirated burners is that you CANNOT restrict the air flow on the exhaust side or you WILL get back pressure at the torch. I don't think there is any way to get around this. It's the R in versus the R out thing. If you have more restriction at the exhaust than the optimum mix on the intake you simply won't achieve optimum mix. This is different than the forced air burners where it will pump what you put into it and exhaust at the pressure you put into it (within reason of course). I am in favor of large chambers because it seems to allow the heat to distribute more evenly. I started out thinking that a small volume would be easier to heat but I have since readjusted my thinking to a WELL INSULATED volume is easier to heat. But the bottom line to a Riel burner is that you need an exhaust hole that is relatively unconstricted. If you can get a good burn at low gas pressure then the chamber can be more constricted because you aren't trying to pump a lot into it.
GA My opinions are my own because I'm to hard headed to take anybody's word for anything.
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Greyangel wrote:

This sounds right to me. I've built single burner forges that only had about one brick's worth of exhaust. Try restacking the bricks so that there is a decent sized hole.
Steve Smith

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That makes me wonder... is there a "rule of thumb" for how large to make the openings based on the size of your inlet pipe and how much pressure you expect to use? Or is it all just part of the tuning process for naturally aspirated burners?
-- Bill H. [my "reply to" address is real] www.necka.net Molon Labe!
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Bill wrote:

There is a formula that comes from jet engine design, but it's three pages long. It has to do with the coefficient of expansion in volume of gasses when heated. Try a chimney at the back of the box with at least ten times the cross-sectional area as the mouth of the burner, and twice as high as the box is deep. If you get the chimney to work, there shouldn't be a lot of backblast through the door when you open it. If that doesn't help, try angling the burner assembly towards the back of the box a bit, so the flow will already be heading the right direction. Once the fire is breathing properly, it'll give up it's heat to the box.
Charly
Fire is a Live Thing, it can't work for you if you strangle it.
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thanks all for your input. When I built the burner for my friend he did not tell me he planed to try to build a forge so small with it. I have always used Ron reil's burner and his btu to cubic inch recipe. And it has always worked very well for me. I am not sure how big he has made the exhaust in his forge. I will pass your information to him. thanks again for the input. jamie.

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<boggle>
This must be a troll. Nobody can be *this* illiterate, can they??
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And here I thought it was rudness that defined the troll...
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writes:

It is! Doug
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Wow, a new low for real trolls!
-- Bill H. [my "reply to" address is real] www.necka.net Molon Labe!
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I have a daughter with 3 undergraduate degrees and working on her masters who cannot spell because she is dyslexic

I
just
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