Burners 101

[ThomasPowers]

Oxidizing flame: Free O2 available to scale metals, rust steel, etc. Generally not wanted in a forge. Especially not wanted when working blades!

Reducing flame: No free O2; in welding, smelting and smithing it usually means there is CO present that will remove Oxygen from materials AKA being rich, (some of us remember tinkering with carburetors!) You reduce ore into metal by removing the oxygen bound to it. Nice for bladesmithing but watch out for the CO!

Between the two is "Neutral": can be tricky to get and hold so you usually get close and use that.

[Frosty]

Chris, I used burn zones when I first started tweaking the T burner to analyze the flame I was mistakenly judging Air propane flames by oxy propane  cues. As has been shown repeatedly three burn zones and cones aren't good standards.

Your flame is pretty rich / reducing it needs more air though you might want to start trimming in 1/16" increments, it's getting close.

Phil: Yeah, you got it backwards, do you want a blindfold?   Ah, just the terminology, your observations were right on the money and blacksmithing has a jargon of it's own and it's evolving daily.

Reducing originally refers to removing impurities from iron in a heavily carburizing fire. Carbon atoms bind with both oxygen and iron more easily than oxygen does with iron.

A pure iron molecule is smaller than an iron molecule with ANY other impurity hence removing the impurity "Reduces" iron to a more pure state. Even cast iron which has considerable amounts of carbon has a smaller molecule than iron oxide. IF I have that straight, I think so but I think a lot of things.

The terms lean rich come from old carburetor tuning days and refers to the fuel half of the fuel air ratio. If it's lean it's not getting enough fuel, rich is getting too much. 

When you find yourself on a forum with people of all ages from all over the world you get some interesting mixes of terminology. We're all adjusting all the time. It gets to be interesting sometimes fun once you get into it.

Nobody is going to fault you for trying to help, well nobody who counts, unless you really get something wrong or dangerous.  We tend to get pretty excited about dangerous advice. 

Frosty The Lucky.

[Cris J]

I appreciate the input nonetheless. I’m a green horn when it comes to any of this. Forging, burners, fabrication you name it. Any input as long as it’s correct is awesome. So thank you oh Bearded One. 

The T is 1x1x3/4” same as the mixing tube 3/4”. The picture is making it much whiter in the center than it appears in person. I’ve tried to adjust the camera so it doesn’t but I’m still working on that. Being oxidized in the flame to my understanding was more orange fanning out at the end, correct me if Im wrong. 

Let’s see if I can paint a word picture. The cone’s center is a light baby-ish blue with very small hints of green at the tip of the center cone, a carburizing/reducing flame I believe like Mikey stated. The second layer of the cone does fade to a purple/blueish mixture, and every so often a little orange flicks out at the very end of the cone over all but it’s very rare. I know I want the green gone so I can get a neutral flame which it does attain after a little bit. 

Mikey what tuning can I do to get rid of the green Acetylene(propane) feather from the get go?

P.S. I know it’s not actually acetylene but acetylene feather is the only name a I can find for it in my reading.

sorry everyone else posts came in later, reading now  

[Bearded Welder]

Well thank you everyone for the terminology lesson, I'm going to re-read this page till that all sticks but definitely opened my eyes to what means what. 

Frosty I like metaphorical dangerous advice, it's alot of fun! But actual dangerous advice.. Not so much 

Cris, I'm probably just as green as you!  

The little orange fllickers you're seeing occasionally are probably flecks of debree from the nozzle, grinding dust, particularlets from an abrasive pad or cut off wheel, they go away after a while. An orange fan at the end of the burn being constant is more propane in the ratio than oxygen I'm pretty sure. 

Cheers, 

Phil the Bearded

[Cris J]

Frosty: Will reducing the mig tip length make it less fuel rich? Or is there something else that can be done to add oxygen into the mixture? 

Bearded One: At least im not alone  I figured putting it here so everyone can see it newbies included would help. 

ThomasPowers/ and everyone I guess: would running the burner on the more reducing side be more desirable then? I plan to blade-smith with my forge once it’s all up and running. I’ve read that reducing flames generally aren’t as hot when forging everything out, but if it adds to the carbonization of the steel I could mentally picture that working a bit better.

Thank you all for the tips and learning on the jargon. Gotta stay up to date on that.

 

[Mikey98118]

Most smiths find a SLIGHTLY reducing flame to be the easiest answer to the problems of perfectly tuning a forge. I agree, in principle.

[G-son]

10 hours ago, Cris J said:

Frosty: Will reducing the mig tip length make it less fuel rich? Or is there something else that can be done to add oxygen into the mixture? 

The position of the end of the tip changes how much air is drawn into the burner. Shortening it moves the tip back away from the mixing tube, and increases the amount of air, i.e. making it run leaner. 

[ThomasPowers]

Generally you can't put carbon in faster than you can scale the surface off when starting out. However NOT removing carbon as it's soaking in the forge is a good thing and especially as people starting out tend to leave their metal in for longer times and take more heats; this can be a big help!

[Mikey98118]

16 hours ago, Bearded Welder said:

Well thank you everyone for the terminology lesson, I'm going to re-read this page till that all sticks but definitely opened my eyes to what means what. 

Neither Frosty, nor Thomas put the matter in the same way I would--and that is exceedingly fine! The more ways it is described the more chance for it to stick in mind

In addition to chemical problems created by lean and over-rich flames, lean flames aren't as hot as neutral flames, and neither are rich flames; the practical difference is that lightly reducing flames have some utility in welding, while even slightly lean flames only have downsides.

[G-son]

On that topic: Has anyone tried a automotive wide band lambda (oxygen) sensor in a forge, to measure the fuel/air mix ratio? Not sure if they survive the heat, but car exhausts coming from a glowing hot catalytic converter isn't exactly cool.

[Frosty]

G-son: I've heard similar questions asked but don't know of anybody trying such instrumentation. There are a couple problems I can see: First is the atmosphere in an exhaust system is closed, only the vehicle exhaust CAN come in contact with the sensor. This isn't true of a propane forge, the exhaust is very turbulent and as the flames of dragon's breath show mixing with ambient oxygen. Two, if the sensor is deeply enough in the forge to avoid ambient air does anyone make sensors that can take up to  2,700f. or more? We're talking yellow heat, not red, twice as hot.

Lastly, (Guess this'n makes three) Is there a need for or is that level of accuracy beneficial forthe home shop level forge? When the HVAC guys service our oil boiler they tune the fuel air by eye through the peep provided by the manufacturer and use the instrument to confirm their eyeball adjustments. They do the same with propane or natural gas furnaces/boilers.

Our main concerns are two fold: Effects on the steel and SAFETY. Any appliance like this WILL produce CO. Even if we got them to run perfectly neutral (stoichiometric) the temps and ambient oxygen would produce nitrous oxides. noxious at low levels dangerous above a threshold I don't know off the top of my dented head. It makes my eyes turn red and sting, if it makes your nose sting, it's getting dangerous, think nitric acid on contact with moisture in your mucus or on eyeballs. 

Anyway, a slightly rich is beneficial in that it prevents oxidization in the forge. There WILL be some ambient air drawn in through the doorway by turbulence in the flame at any rate. HOT steel will always scale up when you expose it to room air unless you keep it coated in flux which gets REALLY messy when you strike it. 

You can adjust fuel air very precisely with a strip of steel. Shine up a long thin piece of steel, put it under the burner and observe the effects. A lean flame will oxidize the test strip, it it scale it's really rich if the shine dulls it's very close to neutral. Look for that point where a tiny adjustment makes it dull or keeps it shiny. You want to stay shiny. . . . Just.

I have some silly thin strip stock 1/8" x  1/2" that's perfect though any thin clean steel works. Test the flame and cool the test strip in water, wipe it dry, shine it up with fine sand paper and it's ready for the next reading. I do this to check my eyeball adjustments, with new burners or especially new forges.

Frosty The Lucky.

[ThomasPowers]

Now I have used an excessively horribly no good very bad oxidizing flame in my gasser on purpose before: I was forging a dragon doorknocker from 1" stock, (the wings were sheetmetal fold formed), and wanted a different surface finish. So I ran it up to very oxidizing and let it soak and when I broke off the scale plates they left a pebbled surface that I liked for Dragon Skin.   Like they say "It's an ill wind that blows no one's exhaust gasses away."

[Frosty]

A perfect example of, "NOTHING is ALWAYS Good, Bad, whatever"  Raku glaze is another mixed example. We've had guys post about how a neutral and especially a reducing atmosphere is a dangerously BAD thing in the foundry. It's been some years ago and I don't recall if the resulting discussion specified the metal being cast, it's been a while.

Adjusting the atmosphere in your forge might be a handy tool in your kit.

Frosty The Lucky.

[Irondragon Forge ClayWorks]

6 hours ago, G-son said:

car exhausts coming from a glowing hot catalytic converter isn't exactly cool.

If I remember from my automotive days, the light off temperature of a catalytic converter is 400-600 degrees F and operating temperature is 1200-1600 degrees F. so I doubt an ox sensor would survive very long in a forge.

[Cris J]

G-Son: Thank you, I’ll be able to pass that along too, my dad is making a forge along side me. 

Mikey: Wonderful tip, in my tuning I’ll see if I can get SLIGHTLY reducing down. I think I’m there for the most part after tuning the Mig tip in 1/16” shaves.

ThomasPower: Another awesome tip I’ll try to put it to good use, and you know minimize the amount of times I leave something in the forge too long  

Frosty: I would never have thought about that thank you (like most things you guys have said actually). It was mostly shiny, but I did see how the burner heated up the bar of a jack hammer that I have, one of my future projects. It did go dull but I’ll see about finding a thinner bit of steel to use

Most importantly thank you all for your wisdom. Safety is certainly paramount I’m sure my wife and soon to be fresh out of the oven daughter thank you as well 

[Mikey98118]

21 hours ago, Cris J said:

in my tuning I’ll see if I can get SLIGHTLY reducing down

People have some problems deciding on whether or not they have achieved a neutral flame, because even when a single combustion front (AKA flame envelope) is achieved," neutral" is a short range, rather than a point of reference. Slightly reducing is also a short range, but it has a beginning point. When all secondary flame disappears, that is the low end of a neutral flame; Thus, where the secondary flame first appears, a reducing flame is achieved. From such a starting point, the smith can decide how reducing works best for which kind of work.

[Cris J]

So what should be done is more along the lines of deciding what works for your particular project rather than achieving a “one size fits all” flame envelope. Like when ThomasPower mentions 

On 4/17/2020 at 10:14 AM, ThomasPowers said:

So I ran it up to very oxidizing and let it soak and when I broke off the scale plates they left a pebbled surface that I liked for Dragon Skin.

 

[Frosty]

Yes. 

Frosty The Lucky.

[ThomasPowers]

Makes me wonder if these new cars are to blame.  Seems like the old ones you were always tinkering with them adjusting things to try to get them working like you wanted them too.  New ones do most of that themselves and I guess folks have fallen out of the expectation that you might have to change things over time.  I know I have ceded my automotive work over to folks with the computerized equipment nowadays.

[Frosty]

I think vehicles are just part of a trend that's been growing for a long time. Not only do you not need to adjust or decide things on your new vehicle, you can't. Our 2015 dodge Journey decides if and how bright the headlights should be but can't seem to read the signs that say you MUST run with headlights 24/7.  I could tell it to run them full time but a computer update changed that and removed the choice. My stupid car updates it's computer more often than the iphone or Kindle. 

Fortunately the car is as stupid as the idiots adding the useless bells and whistles and it was easy to fool, a piece of tape over the sensor did it. 

The trend seems to be folk who expect their appliances and tools to do the thinking for them. I'm meeting kids who've never held a hammer let alone used one who think I can snap my fingers or they can buy the tools and be a blacksmith. No wonder so many folk are committing suicide, they've been taught THEY can't do anything and when they discover tools don't do anything or you're actually expected to produce on a job they just can't cope. 

All they have is their narrow little box. I've tried to help a few but some are just lost. Maybe I should say beyond my ability to open the box.

Frosty The Lucky.

[ThomasPowers]

I was lucky enough to find a 2004 replacement for my 2004 pickup; it has all sorts of vanished things like vent windows in the back of the cab, simple metal keys and a keyhole on BOTH doors; 5 on the floor. (I beat out another buyer who was wanting to get it just to teach his kids how to drive a stick.) Manual windows. Now it does have cruise control which I do consider a great invention.

I find that a lot of "improvements" don't seem to work in the extremes of climate---like moon roofs in New Mexico, I've seen a couple that have been retrofitted with aluminum foil liners...Also cars with limited driving ranges. There are places out here where you can't "gas up" for 100 miles. Anyone know how the automated cars do with dust devils and low water arroyo crossings?  We've had a fairly graphic demonstration(s) on what can happen when a plane tries to contradict a pilot. I guess "2001" is not mandatory watching for system designers nowadays...Daisy, Daisy....

[Frosty]

I've discovered that if the problem doesn't have a code on the shop's computer it's not a problem. Like the Engine warning light on the Journey's dash. It's been on since that computer update a few years ago and when we brought it in. Nope, no engine light. It goes off when they plug in the reader, comes right back on when they unplug it. I guess their "mechanics" don't look at the dash. I've had to almost MAKE the service dept manager take a ride in a vehicle and prove there was a problem. One was a tire that hadn't been seated on the rim. Even though it spun balanced fine it shook the car. Nope, there's no problem, see? Here's the balancer readout, no need to test drive. I actually had to lean on the store manager's desk to pry him out and didn't take a 1/2 block to convince him there WAS a problem. Turns out they don't even look while the tires seat, let alone run a hand around the bead. Nope, it's a TIRE MACHINE, it takes care of it all. 

I like cruise control too, it's a good way to avoid tickets but a seriously BAD way to drive on wet or icy  roads. 

I still haven't heard from Tesla about how long the heater works at -40f. What good is a vehicle with a 300 mile range? I suppose if you live in a city maybe. Is your electric bill cheaper than gas? Not here, it isn't even close. Maybe it they get their heads out and develop pebble bed reactors we'll be able to afford useful electric vehicles. 

Think any of the younguns have thought through what REAL AI probably means for human beings? 

Frosty The Lucky.

[ThomasPowers]

We have a retired astrophysicist out here who is very happy with her battery assisted hybrid.  She has solar panels on her house and tells me that in the last 1.5 years she has bought 2 tanks of gasoline for it.  Now she only drives around town and up to the city on the interstate.  The geologists I work with would trash such a vehicle in a month.  One size does NOT fit all no matter how much advertising would like us to believe it.  I currently drive my old truck to work as it will be a donation when we get out of quarantine and so the more miles on it the fewer on my "new" one. It has the check engine light on and our mechanic says "Don't take it on any trips out of town".  Our mechanic(s) also test drive our vehicles after a fix involving engines, drive trains, suspensions, etc.

[Mikey98118]

Nicely put, and interesting, too.

[Alphafarrier]

Is there ever a time when you would want an oxidizing flame?  

In Mikey's book he talks about a neutral flame being the hottest, hotter than either oxidizing or reducing.  I was messing around the other day, and when I ran my burners with the most oxidizing flame I could, steel seemed to heat up FAST (and then scale up badly and then start burning if I left it in there for any time after it hit yellow, of course...).  Is this just my imagination?