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Forge Burners 1,2,or 3?


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Hello,

I plan on learning to work steel on a little knife making forge.  and then begin to make knifes and small art.

Can someone enlighten me as to the pro's and cons of 1 burner vs. 2 burners.

I am assuming it is more evenly heated over a greater surface area? Eliminating hot spots. 

  Would one burner suffice, or would it be more of a headache than it is worth?

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I run a single burner forge that I built from a 20# propane cylinder. Works great for me. Hot enough to weld and has enough turn down for light work and Heat treat. Blades much more than 10-12" may require something a little larger. Or have a hole in the rear that steel can pass through.

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that's good to hear... single burner are cheaper. i am not in the position to make my own yet.. someday i might want to do that.. but i want to get a handle on using them for a couple years... then i might know what i am looking to get out of my forge , and can make a more sound decision regarding design.  i was looking at the diamondback forges.. they seem to be the cheapest i can find .. single burner knife forge $350

thanks for the reply.

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You can only work so much of a length of metal at a time with a hammer and an anvil, a one burner forge is sufficient for several professional knifemakers I know, who do everything from little skinners to massive bowies.

 

Heat treating of swords can require a totally different set-up.

 

I suggest that you read thru the archives here, and at Don Fogg's site and forum. Attending an ABS or other knifemaker hammer-in would be another way to drastically shorten the learning curve.

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I just built a little micro forge for bladesmithing and tool making.  The interior chamber is only 3.25" diameter and 9" long.  I use a single 3/4 inch burner to heat it.  The great thing about the small chamber is it heats up really fast and gets really hot.  You'd be surprised how much work you can do in a small forge like that.  I wouldn't be able to forge a shephards hooks in it, but no single forge will be able to do everything.  Buy or build a forge that is going to best suit what you want to do.

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my main forge and all the teaching forges i use are one burner forges.

 I have made hundreds of kilos of damascus in my main one burner forge .

 there is a tendency to overcomplicate forges .

 one decent burner is all you need unless you are forming large sheet or bending very long lengths.

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Lendlas,

 

Assuming burners of the same size, two will heat faster (much faster) than 1 and sometimes use less fuel.  I've found that in my 7" diameter, 12" long forge, it loses heat faster with just one burner and requires more fuel to compensate.  When I switched to two burners the forge heated up faster and retained the heat easier.  While the faster heat was expected, the heat retention I can only attribute to the fact that one burner is trying to heat the entire forge and losing heat at both ends.  Two burners each heating half the forge operate at a lower fuel flow and it seems to be less that half the one burner comsumption.  That is on MY forges in MY shop and may not be universally true.

 

What I really wanted to address is your concern about 'even heat'.  IMHO this is the most overrated aspect of a forge!  I've built a number of forges, mostly venturi forges (see other venturi threads) and a couple of blown forges.  After spending hours designing and building a venturi forge that had a great 'heat/flame swirl' and a pretty darn even heat distribution (checked with a pyrometer and various locations inside the forge) I discovered that it makes very little, if any, difference in forging perfomance.  What - how can that be!  Conventional 'wisdom' says even heat is the 'holy grail' for forge design- the 'swirl' is important!  NONSENSE.  No matter how even the heat is inside the forge, any metal you put in will heat unevenly!  Take for example a knife blade - the tip is thinner that the base, the spine thinner that the edge.  In a forge with perfectly uniform heat the tip and edge with heat faster and get much hotter quicker.  Even if you put in a perfect sphere of metal in a perfectly uniformly heated forge, it will heat unevenly.  If it rests on the floor of the forge the bottom will heat slower, if you hold it with tongs where the tongs touch it will be uneven.  I've tested this and know it to be true.  That is why you see experienced smiths, blacksmiths and bladesmiths, moving their work pieces around within the forge.  This is perhaps most critical when heat-treating.  Getting the most uniform heat in a piece of steel before quenching is critical and expecting that to happen just by putting the workpiece in a uniformly heated forge is a recipe for failure.  Best case it will simply heat unevenly, worse case you'll burn away some metal while leaving other parts below critical. 

 

While I've done a fair amount of forging (and forge welding) myself, I've watched many, many others, particularly bladesmiths, forge metal.  I have yet to see one achieve an even heat without moving the piece around inside their forges.

 

Unless you can design and build a forge that you can regulate AND adjust the heat in minutely controllable zones, don't waste your time trying to build a forge with uniform heat.  Better to spend you time positioning and repositioning your metal to heat evenly. 

 

Is the concept of a uniformly heating forge something to aspire to - or just a marketing ploy to differentiate one commercial forge from another or justify the cost - you decide, I already have.

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