burnner

[Buzzkill]

I have been very patient on here.  I've asked a *very specific* question which I have yet to get an answer to.  I have repeatedly stated that I'm not questioning the conclusion, but I want to know the how and the why of the phenomenon.  I'm not after an argument.  I'm interested in learning something I don't know.  The way to do that is ask questions and research, both of which I have done without a good explanation being presented in either case.  All I have gotten is essentially, "just accept that this is the way it is."  I did that long ago.  I have only asked for an explanation of *why* it is that way it is from the beginning.  Neither you nor anyone else has provided anything resembling an answer to that question.  So you are right.  Enough!  If you don't know then you are in the same boat as I am.  If you do know and can enlighten me I'm more than happy to read the explanation.

Just in case it wasn't clear before the question is still this:  "Why is the formation of water vapor more of an issue when burning methane in a naturally aspirated burner than it is when burning propane in the same setup?"

[ThomasPowers]

Thought I posted this before:   CH4 is Methane and C3H8 is Propane (actually we get a mix...)  if you are going to burn the same amount of C you get 12 H's with methane instead of 8 with propane;   half again as much H to form H2O.

Don't recall not being able to use Methane for forging; just takes more and has the extra H2O formed to deal with.  Even my old pickup truck will get up to highway speeds; just takes longer to get there...

[Charlotte]

I repeat: One of the nasty things that water vapor does <aka Steam> is combine with iron molecules to produce black oxide iron oxide and hydrogen  which then combines with atmospheric oxygen.   In days to Steam power  some terrible explosions were tied to the production of hydrogen from the contact of steam with red hot Iron.  The reaction of steam and Iron is one of the reasons it is hard for a gas forge to produce the nice slick looking forge work that is so easy to produce with out thought in a solid fuel forge. 

ie more water more problems

The Net   reaction is to be less efficient.

[ThomasPowers]

I have no trouble to get better looking work in my propane forge than one of my coal or charcoal forges. I just tune it to reducing when I'm bladesmithing or doing a task that requires a fine finish.  Most of the explosions I have read of with steam were not hydrogen but  water hitting hot metal causing a flash of steam that blew the boiler---like the one that happened in Ohio a decade+ ago with a steam tractor that blew because the sight glass was broken and so the water level got low and he was on a hill and when he leveled out too little water on two hot an interface.

[Buzzkill]

I think I'm about done beating this dead horse on here, but I'll give it one more shot to see if I understand it correctly.

The combustion of both propane and methane are net exothermic reactions including the formation of water vapor.  So, if I understand what you are saying, after it forms the water vapor then absorbs more heat than was given off when it was created and whisks it out of the forge, thereby reducing the flame and forge temperature.  This would also happen with propane, but to a lesser degree due to the lower ratio of water molecules formed when burning propane compared to methane. Is that what you've been telling me?

[Charlotte]

ThomasPowers    I totally agree that it is possible to produce decent work out of a propane forge.  The remark is directed at  the learning curve of propane forge operation.  The beginner is likely to  have problems in getting and keeping a forge tuned for a nice balance between too much reducing and to close neutral/oxidizing. 

Hydrogen explosions created by superheated steam an Iron are part of the history of the steam era.

7 minutes ago, Buzzkill said:

I think I'm about done beating this dead horse on here, but I'll give it one more shot to see if I understand it correctly.

The combustion of both propane and methane are net exothermic reactions including the formation of water vapor.  So, if I understand what you are saying, after it forms the water vapor then absorbs more heat than was given off when it was created and whisks it out of the forge, thereby reducing the flame and forge temperature.  This would also happen with propane, but to a lesser degree due to the lower ratio of water molecules formed when burning propane compared to methane. Is that what you've been telling me?

In short form yes.

[Mikey98118]

"Absorbs the heat" is correct, but can be taken the wrong way too easily. Some chemical recombination actually produces heat; its exothermic. Single hydrogen atoms combining into molecular hydrogen (H2) in an atomic hydrogen flame produces a lot more heat than oxyacetylene combustion for instance. Other recombination will absorb heat; its endothermic. As to why methane's recombination of hydrogen and oxygen atoms into water vapor in the secondary flame would absorb heat so much more than any other fuel gas, I don't know; just wasn't that interested.

I'm basically ruthless about tools. I care how well they do a given job, and don't do more than minimal research as to why something is so, once I know that it definitely is so. 

[Buzzkill]

Thanks for chiming in Mikey.  I get what you're saying about moving on once you've determined a fact to be true.  I've found that if I want to start tinkering with something it's better for me to know the "how" and "why" to avoid spending a lot of time messing around with something that was flawed in concept to begin with.  There's nothing I hate more than spending a bunch of time on a failed project only to discover if I had asked the right questions before I started I could have gone in a different direction.  They are still learning experiences of course, but frustrating ones.

[Mikey98118]

Charlotte,

In the first place, congratulations on accomplishing a very difficult task; especially if you are getting the resultant gas jets long enough. But a twist drill will leave internal scarring in the hole, which will interfere with with laminar flow in the gas stream (a definite no-no). You will find capillary tube to b e more efficacious, and a lot easier to deal with in future.

Frosty,

There is a lot to be said for using a jewelry torch to heat coffee-can and smaller forge sizes. But the torch nozzle will overheat and become an expendable, unless a flame nozzle is attached to it.

[Charlotte]

18 minutes ago, Mikey98118 said:

Charlotte,

In the first place, congratulations on accomplishing a very difficult task; especially if you are getting the resultant gas jets long enough. But a twist drill will leave internal scarring in the hole, which will interfere with with laminar flow in the gas stream (a definite no-no). You will find capillary tube to b e more efficacious, and a lot easier to deal with in future.

I find drilling to be a piece of cake with years of practice.  And second I don't care if it is laminar or not since I create a critical orifice.  Typically operate forge at 25 to thirty psi. With one set up I used 40 psig.   I have my idiosyncratic design well in hand.   I don't share my design because it relies on understanding how flames work and how read the results of adjustments.  My first job was running gas fired annealing furnaces for a major steel mfg.  so I got a close up hands on experience with Industrial practice. That was in the days before digital controls  

[Mikey98118]

Frosty,

I know you didn't, but most of what I explore these days are post publishing discoveries, and the main value of the book is all those piles of background information that most people who've built forges already found out the hard way. I wrote the book for art majors who are being cheated by our not so wonderful school system, and who discover the hard way--after graduation--that they don't posses the tool skills to do much with their 'education.' That was my mission, but once it was accomplished I was free to pursue more advanced methods, which take basic shop skills to employ;  much more fun.

 

 

[Mikey98118]

Frosty,

i should have pointed out that MIG contact tips are labeled according to the wire size they feed. .023 contact tips are sized to feed .023" MIG wire; their actual hole diameter is .031" to buy something with a hole diameter of .028" or smaller the builder must use capillary tube, buy a standard gas jet (too short), or drill the hole smaller, and then employ torch tip cleaners to smooth away internal scarring, while bringing the hole up to finish size.

So, if a person wanted to improve an existing 1/2" burner with minimal trouble, they would buy capillary tube in the form of a dispensing needle from eBay, drill out an existing .031" orifice a few thousandths, insert the needle into it, and swage the copper MIG tip down tight around it. Afterward it could be screwed into the burner's gas pipe just like the tip it was replacing. Do not increase hole size in copper more than a few thousandths at a time or it will cease the drill bit and snap it off.

[Mikey98118]

To all here,

You don't have to buy my book to discuss it knowledgeably; in 2006 it was pirated and elctronic copies of it are still available "free" all over the net. At one point I counted 120 different sites offering free downloads; a few of them can even be trusted! And why would I mention this? Because my original contract expired; the guy who bought my publisher out sends me royalties in return for the PRIVALEDGE of publishing it, but I have no contractual obligations to him. Besides, book sales have nearly doubled since it was pirated! Just input Gas Burners for Forges, Furnaces, & Kilns followed by PDF. The percentage of people who felt they were getting full value for money spent always bought their own copy, and others never would. Pirating has more than repaid a few lost sales in maximum free advertising. Seldom does something good for so many come about from such bad intentions on the part of a few :-)

[Charlotte]

Mikey98118    Just so you know when people ask me about burner design   I recommend your book.   I have a copy of it on my book shelf.  I don't share my system because although it works for me it is one that I developed as a hybrid system.  Your  books burner builds should produce predictable results in the hands of competent builder. I don]t think any better praise than that can be had. 

I began building  my system quite a while before your book was published.   If I had seen it first I might not have developed mine.

 

[Frosty]

No need to point that out I was a certified welder decades ago when using argon for tig or mig was new fangled tom foolery to the old dogs. So yeah, I never refer to a 0.023" mig contact tip as a 0.023" orifice. I couldn't tell you what the diameter was though and I'm not getting out the gauges to find out, they vary anyway. They work so I'm good.

If you want to insert a dispensing needle in a mig tip sweat it, swedging is more trouble than it's worth and less reliable.

I know what you mean about modern education, I'm getting kids ready to graduate high school who've never swung a hammer of any kind and on a couple occasions who couldn't figure the area of a square let alone a circle. I find myself teaching some of them basic hand skills and after a couple sessions without mastering drawing a point on 5/16" rd stock they tend to give up. It's sad but some stick with it so I show them everything I can.

Why would you insert a torch far enough into the liner to burn it up? You only want to prevent excess outside air induction and close is good enough they're designed to run a little rich anyway. If I use my oxy propane torch I'd have to extend the tip into the chamber itself a ways to damage it.

Most of this is a matter of paying attention to your tools while you tinker. They speak plainly enough if you pay attention.

Frosty The Lucky.

[Mikey98118]

Charlotte,

Now that's what I call an impressive background!

[Mikey98118]

Charlotte,

Then I'm glad you didn't see my book first; there is a place for every decent burner design; the more the merrier. Now, all we need to do is lure you out of your reluctance to discuss yours :-) And yes, I do appreciate your unwillingness to spread knowledge that may lead the careless into trouble. But, you can  share the incites on combustion heating that you've collected over time. And I will be "siting in the front row" with my ears ready to be filled.

[Mikey98118]

The lack of a carbon = carbon bond looks like an exiting clue only until we consider hydrogen combustion, which is very hot without any carbon present at all, and should present the worst recombination example of all, but doesn't...unfortunately, the information posted on the Net is dependent on peoples' desire to post it; and that seldom is unselfish. On the other hand, once we leave the Net, information is a long way from free.

[Mikey98118]

TJ and Frosty,

When I used the term "soft flame" It was without taking what the term would mean to others into account, and that was wrong; apologies for that.

To me a "soft' flame doesn't even have to be reducing; a neutral primary flame, which has more than a wisp of secondary flame is a soft flame; I need to find a less confusing term to replace that mental image.

[Frosty]

No misunderstanding with me Mike, jr. high metal shop class don't you know.

A soft flame is one without much velocity so is whispy and soft, often called feathery. Adjust an oxy whatever torch to a rich flame without overdoing it and the tertiary flame is soft but has absorbed enough atmospheric oxy to be neutral. We used a soft flame to fire stain wood and doing torch enamel and tin large surfaces say car fenders before Bondo. Soft flames whisper and are also known as a "breathy torch."

Frosty The Lucky.