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Hi so im a not so beginner who is looking to upgrade his forge. I had a small forge made out of soft firebricks and it is a bit too small and i would like higher heats with more efficiency. Do any of you have recommendations for how to go on with my next forge? Or if I can get better efficiency with a dual burner design?

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Welcome aboard Phoenix, glad to have you. If you'll put  your general location in the  header you might be surprised how many members live within visiting distance.

You're going to have to provide us with more information for any of us to be able to help. Terms like "Small" don't really tell us anything without context. Some guys on Iforge work with forges that would think of the Small forge as the one that only held one rail car's worth of stock. A friend of mine's small forge is 1 1/4" dia x 6" long. 

Higher heats? Same same. More efficient than . . . ? 

If you asked something like. I have a 300 cu/in single burner forge but it won't reach welding heat and goes through a 20lb. tank of propane in about 6 hrs. We can work with something like that, we'd ask you a few questions for clarity and want some pictures. 

We need details and a couple pics.

Frosty The Lucky.

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In my opinion there are three easy steps to improving efficiency of a gas forge (most of which will also allow you to operate with a hotter interior as well):

  1. Improve the thermal envelope:  Improve the forge liner so there are less conductive losses through the skin of the forge.  Increase the insulation quality and get rid of any thermal bridges that allow the inner heat to be transmitted to the exterior (especially around the openings) by careful placement of insulation and forge structure.  An ideal forge should have a outer skin that is only a few degrees above room ambient temperature.  Most of us are happy with a forge that has a skin that doesn't rise above 110 deg. F
  2. Reduce the radiant losses existing the door and any exhaust ports.  A good, insulated (see item #1) door that closes almost all the way without thermal bridges and is easy to operate is best.  This is where a forced air burner can give you a more gas-efficient forge (IMHO), because you can have your door closed much further and don't have to worry as much about backpressure interfering with the induction of a NA burner.
  3. Improve the burner design:  A burner that is designed correctly for the type of forge it is used in can make a big difference.  You want virtually complete combustion inside the forge envelope (just a little dragons breath of combustion outside to avoid overly oxidizing your steel) with a short, slow, bushy flame, especially for a NA burner where you can't close down the door and restrict the exit of the hot exhaust.  The slower the flame, the longer the heat stays inside your forge, the more it heats the inner walls and those walls radiate onto your stock.  This is one of the advantages of a multi port outlet (ribbon burner), which creates lots of smaller flames over a larger area for the same fuel gas input as a single flare.  The burner also has to be correctly sized for your forge interior.  It is possible to have both a burner that is too large and one that is too small.

Of course there are other more complicated tricks to getting better forge efficiency, including using heat exchangers to preheat the combustion air, temperature controllers to modulate gas and air to achieve setpoints that optimize forge temperatures for different operations (even potentially shutting off while you are out of the forge), and optimizing your forges thermal mass for the operations you expect to perform (high mass forge for large stock forging and needing to open and close doors regularly, low thermal mass forge for someone who only forges for under an hour a session and mostly small stock...), but those are more complex and potentially prone to lack of return on investment.

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Sorry, i was on a trip and i just got home. The forge is made up of 8 firebricks, and there are 2 on each side. I have bricks on the doors to trap heat. The regulator is max of 20 psi. It lasts a pretty long time on a small tank of propane

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Location Phoenix, it can make a real difference. 

What kind of bricks? What kind and size burner? How do you want to change the: forge, size, shape, etc.?

What do you mean by efficient? That's a really broad term it can mean many things, you need to be more specific as to just what you want or we can't do much of anything to help.

Frosty The Lucky. 

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