Does metal care how it gets hot?

[George Geist]

I've never seriously looked into this but when I first came around coal forges were pretty much standard equipment for everybody. Gas forges were just being introduced in fact I believe I had one of the first Mankel models.

Back then it was pretty common belief that coal fires added carbon to the steel whereas gas either didn't or some folks said removed some. Have no idea as to these claims but that's what was thought at the time. Coal definitely better for welding IMO anyway.

George

[ThomasPowers]

Wow I have 100+ year old books that mention gas forges; you are old!  They were mainly in Industrial situations and schools; my middle school in 1970 had a johnson natural gas forge in it for the kiddies to use. Small portable propane forges are a much more recent thing.

I prefer to weld with coal; but I notice that many if not most  of the professional knifemakers making patternwelded and wootz steels all use propane; so it's definitely a personal preference.

As for reducing vs oxidizing---that a function of your forge's atmosphere and coal or gas forges can be tuned to be oxidizing or reducing. There are a lot of "disproved beliefs" about  putting carbon into a piece in the forge.  It can be done, (oroshigane is a classic example); but typical forging has the surface of the steel scaling off faster than the carbon migrates in.  And a common urban legend that all the folding and welding steps used by japanese swordmakers puts carbon into the steel is pretty much backwards.  Often they start with steel that is nearly 2% carbon and end up at 0.5% carbon:  *NOT* an increase!

[Frosty]

We had Johnson Appliance gas forges and melters in jr. and senior high schools in the '60s and they looked pretty old then. Probably not a 100 years though.

The linear burner Ron Reil based his on has been around since the middle of the 19th cent. as a common home build burner, commercial gas burners have been around longer, mid 18th?

Frosty The Lucky.

[George Geist]

Guys this is from the perspective of a guy who started out running from place to place shoeing horses out of a pickup truck for $25 a head when gas was about 0.50 a gallon. I'm fully aware of gas used in shops but portable propane forges didn't come around till the late '70s in the world I came up in.

As to my being an old guy, yeah......Somewhere I have a picture of me at about 6 or 7 years old forging in the Williamsburg shop myself flanked by two guys all of us wearing tricorn hats and colonial clothing. Although I wasn't really raised in the 18th century sometimes I feel about that old.

Now, for the $100,000 question. Do any of you guys know why it took so long for modern gas forges to become available???? The answer is really cool so let's see if anybody knows

[Frosty]

Interesting George, I think region might have a lot to do with who was using gas vs. coal forges in the '60s, that's as early as I remember watching a farrier. I grew up in S. California and the first time I saw a horse shod the farrier was using a propane forge on the tail gate of his pickup. That would've been when we were shopping for our first horse, Sailor a retired race horse cir. 1961.

Coal isn't very common in S. Cal. but I'll bet it is or was available in almost every feed and seed, hardware, etc. not to mention companies supplying heating coal in Pennsylvania.

When I was a kid we all KNEW horse shoers used gas furnaces and blacksmiths used coal REAL forges. Heck, I had the Wagon Train set with little: plastic settlers, wagons, horses, bow toting Indians on horse back and a blacksmith with a masonry forge. The downside being the blacksmith's toe was attached to the anvil block, poor guy. Of course we all know the blacksmith was REALLY strong so walking around with an anvil ad wood block attached to his toe wasn't a big deal. Heck, he could just kick the attacking Indians if they broke through the ring of wagons!

Uh oh, got side tracked again didn't I guys. 

Frosty The Lucky.

[Scoot]

Metal doesn't care...............We care.

[jlpservicesinc]

Well since we are all over the place on this one..  Let me add.. Metal does care.  Well it depends on what kind of metal.. HSS don't like sulfur or phosphorus when being heated in a coal forge. 

As for a coal forge..   It has 3 zones based on how much air is being pumped in,  These 3 different zones change within the fire depth as the amount of air goes up or down. 

Unless the fire is high enough that nearly all the O2 is burnt up before it can find the steel/alloys being heated.. Carbonizing.

When I have the Bituminous fire setup for forge welding and I'm in the groove the 1018, A36, can be a nice white color and won't throw sparks until it is removed from the fire.. Then it will start to sparkle as if it is over heated..  Because the steel is in a neutral atmospere it won't give off the carbon atoms till it has more oxygen... 

So with that being said.. Pretty much any carbon fuel source can have  Decarb, neutral or Carbonizing flame.. A/O torch, Gas forge (with choke), coal forge, wood forge, oil forge.. It just depends on the air to fuel ratio.. 

Do the steels care.. Heck yah.. Some do, most do..    For most applications I would agree that I think people care and engineers care even more..   There are so many variables when forging iron/steel by hand that if it was just one way or the other we as humans would have never made it out of the pond.. 

How many of us on here actually agree there is a right or wrong way to forge something.. I mean excluding rookie mistakes or forging errors all together.. 

The whole process of war and making better weapons has driven from bog iron to carbonized wrought irons. to mass produced super alloys.. Ok well 4140's.. 

The forging process either by hand or by machine has stayed consistent for 1000's of years.. When I say consistent I'm saying that it's still done in air.. (barring super alloys)

Anyhow.  the point of external vs internal temperature was a great one.. Induction heating in a neutral environment would be pretty cool as there could be a vacuum like in space and it wouldn't matter. Or would it???? 

 

Thanks.. Just taking up space..