Mikey98118

Charles, quoting an article. passes on the author's statement that "...the distance the flame travels before hitting an obstruction matters, too close to the floor/wall and the fuel is not completely consumed. " I don't find this to be so; in fact, once the forge interior becomes yellow hot any decent burner design should put out flames that are completely consumed, obstruction or no. What does commonly go wrong when sufficient distance isn't provided, is that any super-heated oxygen molecules escaping the primary flame envelope will cause a lot of scaling on work surfaces before they are consumed in secondary combustion within the forge. The simple solution for such a problem is running a reducing flame; of course, that can lead to other complications...best to design both forge and burner as well as you can, and only employ educing flames when they are the best option for the job you're doing :-) Tunnel forges normally have down facing burners set at about a twenty degree angle to promote swirl, instead of top dead center, which is also found, but is far less common. Nearly every gas forge has a kiln shelf or hard fire brick floor that the burner is aimed toward in order to spare ceramic fiber insulation from direct flame impingement. But what would happen if each burner were facing upward at a twenty degree angle against a cast refractory flame impingement ring, so that there was loads of distance before it hit the work? This would also end the so called "chimney effect and greatly reduce interference from back pressure through buoyancy. Shall we discuss this possibility? I plan to use it in my next portable forge.

I used MAPP in the shipyards for years; it was superior to anything else for torch cutting, heat bending, and silver brazing. I listened to both sides of the debate among welders as to whether it was good for flame welding carbon steel for years, but my interest was low because my employers were the ones paying out big bucks for acetylene on special pipe welds. After the shipyards closed, I spent another sixteen years working in small boiler shops and ship repair projects for the fishing fleet; both kinds of employer mostly used oxyacetylene. By the time I was personally concerned about the efficiency and cost of supplies, MAPP gas was a memory. However, propylene gas could be purchased for only a third more cost than propane from welding supply dealers, if you bought your own D.O.T. approved cylinder, and while both fuel gases were way cheaper than acetylene, they also both use three to four times as much oxygen in the flame. Now, oxygen in many places is reasonably priced, but Seattle isn't one of them. If you're an industrial customer, its cheap here. If you're a hobbyist or small business owner, get ready to be sheared...

I can only agree with Charlotte. My three favorite examples of corporate bonehead thinking are a little yellow 150 amp gasoline powered welding machine that could be lifted by one person and had a true hundred percent duty cycle. The manufacturer was bought out by Lincoln and shut down, so it wouldn't compete with their 150 amp piece of junk welding machine. There used to be a rubber welding gasket sold which wrapped completely around welding helmet light filters, covering their edges on three sides; it totally prevented light leaks, cost two bucks, and lasted for years. The manufacturer was bought out and production shut down; thereafter we all got to replace our one dollar (but you needed one on each side of the filter) oil impregnated paper gaskets about twice a year, and light leaks were a constant problem. Finally, a well known manufacturer of auto-darken welding helmets came out with a model that had a green LED light just above its lens. When the auto-darkening filter was in rest state, it was the equivalent of a #4 green light filter, and the LED would provide just enough green light, which the filter did not interfere with to allow the operator to change position before starting another weld. The flaw in this system was that they forgot about weld berries, which over time would destroy the LED. Rather than provide a protective clear plastic filter for the LED, incorporate it into the auto-darken filter (where it would have been protected) or sell quick installing replacement lights (after all LEDs are cheap), the company discontinued the helmet! So, if you want a high production capacity helmet for short welds, you must build your own. When I was a working stiff, all this stuff just made me grin; after all, work was dog eat dog, and everything bad only tended to cripple my competition, while I did workarounds. The working man's world is still dog eat dog, but I'm out of it; so don't mind teaching "them as listens."

Frosty, I only took one metal shop class, and the only ting offered was sheet metal. This wasn't from lack of interest, and I did get to work summers, weekends, and holidays in my father's ornamental iron works from age twelve (mostly loved it), meeting old timer weldors and construction boomers; picking up a lot of general knowledge from them and from dad. Outside of sheet metal shop in junior high, all the shop classes offered in my school system at the high school level were electronic or automotive classes. I hope shop classes have improved in southern California over the last fifty years, but somehow doubt it. Blacksmithing, brazing, and welding would be excellent subjects for teenage boys to be exposed to. Trouble is they are expensive classes to run, as compared to baloney subjects that only cost for the light bill, and a teacher's salary. None of that hurt me, since all my education except simple math and writing skills was learned outside the school system (I learned to read before age five, along with my sister and brother; first from holding contests reading billboards and comic books, and later at the town library) Post grade school, everything I learned was in spite of school; not at it.

I just knew if I could get Frosty to talk about brick pile forges something good would come up, and sure enough someone responded to his comment about painting the bricks with kiln wash with a better finish coating. Mentally, I hugged that idea to me and ran around in gleeful circles with it. Obvious; yes, but all good ideas are obvious...after someone else points them out! This little detail would make all the difference in how long insulating fire bricks last, and would create a tough enough surface that ITC 100 could be painted on one face to further increase efficiency.

Frosty, I first encountered this as the nine diameters rule of thumb (in Ron's pages?), and through experimentation found that with my jet-ejector design it could be as few as eight diameters and as much as ten. With the shorter lengths producing a more powerful swirling flame and the longer lengths producing smoother flames (which are more desirable for brazing work). My vortex burners require fourteen diameters for a smooth flame. It seems likely that length to diameter ratios change according to burner design, and the "industry standard" is a little shaky, yes?

Remember that we are talking about braze welding; not silver braze "sweating." I've even braze welded with one of the burners in my first book (and wrote a short chapter on how to do so), and also remember that I stated "being able to do a thing doesn't mean we can do it well." Pinpoint heating is the key to professional grade braze welding, and that depends on a super hot flame. Some braze welding is even done with the arc from a TIG machine. Braze welding also used to be done with both twin carbon arc and single carbon arc "flames" for the same reason. MAPP gas isn't produced anymore; it has been replaced with propylene fuel gas since 2008; weather or not it could successfully be used for steel welding was a subject under debate. On the one hand a friend of mine used it for welding steel tubing. On the other hand It was not used for any certification tests, which suggests to me that it wasn't quite "up to snuff." If I were going to flame weld steel without employing acetylene, I would use a twin carbon arc, to supply the excess carbon from its flame, which can otherwise only be supplied by acetylene, for it is claimed that the carbon content transferred to steel from an oxyacetylene flame is the reason MAPP gas wasn't supposed to be used. I don't personally know whether or not the flame's carbon content was the actual reason, as claimed, that MAPP was no good for welding steel, or it was an urban myth. Back when I had ready acsess to the tools and materials to make these tests I was too busy making a living instead :-)

rjs, Nothing but a TIG welder comes close to an oxyacetylene torch, and I never liked using TIG all that much. Twin carbon arcs didn't just fade away; they were quietly done away with by their own manufacturers back in the sixties; that was when weldors who had been using less than safe eye protection started showing up for eye surgery do to collective damage over the course of their careers; it was during that period that safety regulations on helmet filters were tighetened up considerably. Many old filter designs were removed from the market, and twin carbon arcs made by mainstream American manufacturers were quietly "dissapered" at the same time.l Why you ask? Because carbon arcs put out more UV than any other arc source, and companies like Forney were shaking in their boots for fear of potential law suites. For those of you who don't go back that far, a liberal revolution was going on in America back then. Today auto-darkening helmet filters have "come a long way baby" and can easily handle the increased risk from this tool. But, in the meantime, the American Welding Society has leaned on Uncle Sappy to get absurd safety standards put in place for carbon arc heating/welding. How do I know this? Because, at the same time carbon arc gouging, (an important industrial process $$$), which puts out exactly the same amount of UV for amps used has much lower requirements. I wrote to the department involved, and they answered that they "were just following AWS recommendations; on querying them, I was referred to their "safety standards commitee," and eventually to the single individual who wrote the recommendation. I asked for his justification, and never heard back from him. For those who don't know it, many welding experts have membership in the AWS (I suspect, in order to receive their magazine, which is excellent), but it is manufacturers and big time distributors who run it. There is a lot of money to be made selling TIG machines and supplies, and very little money to be made selling twin carbon arc torches, so even though the generation who might have sued over eye damage is long dead, it's still all about money. Isn't 'democracy' wonderful? "Truth, justice, and the almighty buck."

rjs, They claim it can be used for brazing; by this we assume they mean hard brazing. What the American Welding Society terms braze welding and the Brits call spelter brazing. We assume this meaning because silver brazing uses much lower temperatures that can alredy be achieved by any air-propane torch. Since their claimed temperature of 4172 F is within hard brazing range, technically speaking it should be able to do so. But here's the catch: just because we can do a thing doesn't mean we can do it well. An oxy-propane flame is about 4800 degrees and it doesn't do braze welding well. You want at least an oxy-propylene flame (5200 F), and oxyacetylene is better (5800 F). We have all experienced the frustration of trying to overreach with a poor tool. If you want to braze weld and don't have an oxyacetylene torch set, I would recommend using a twin carbon arc instead.

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.

Charlotte, Now that's what I call an impressive background!

A "T" burner will have completely different dynamics from one of mine, so most of the advice I can't comment on, but you definitely DO NOT use the same diameter gas orifice in two different burner sizes.

I'm simply not that trusting of foreign made tools. An American manufactured tool exposes the manufacturer to devastating law suit losses, if the tool is defective and proves dangerous. But, try suing a French manufacturer in a French court "Yankee"! So, when I see normal safety concerns ignored by a manufacturer, who is beyond retaliation, I "just don't go there."

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 :-)

You're welcome, MP. Hope you've been following along recently on all the gas forge discussions, If so, you'll already know that you want to buy extra MIG contact tips and insert .028" inside diameter dispenser needles into them. You will then have the ability to fine tune the forge even further; not that you won't also want a pair of .023 MIG contact tips with the original .031" holes left as they are, to give a slightly softer flame for forge welding. What you will not have heard, because it is only mentioned in the updated version due out next year, is that I've modified my original advise about employing 4-1/2" angle grinders for all the work, to include hand held rotary tools for cutting out the air openings. In 2004 these tools and their accessories were just too expensive for most of the starving artists the book was dedicated to; today this isn't true. If you feel that both tools are too great an expense, choose the rotary tool over the angle grinder. Also Dremel's 1-1/2" spring loaded EZ mandrel, unlike much of their overpriced stuff, is worth every penny on this kind of work.

I've looked at the photo, and it seems unlikely that uptake of exhaust gas into burner intakes is the problem; not with the burners offset like that. But, he doesn't say whether or not the burners have flame nozzles attached, so lack of sufficient back pressure just could be his problem. I think the addition of flame nozzles will prove to be the simplest solution for it. Of course your idea of redirecting exhaust gas further away the the burners with temporary structures is painless enough to be worth doing, just to eliminate the possibility. Stuffing a firebrick under the burners within the furnace should be a fairly painless way to check out the back pressure possibility, too.

The ignition temperature of propane is 470 C; well below even the heated air figures, so I would not trust the safety of this tool.

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.

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.

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.

Thanks, Sharpshooter, I do love hearing specific details on a new (to me) subject.

"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.

Frosty, All that information and I didn't directly answer your questions. Yes, different burner sizes are that important to people working other aspects of the metal hobbies. But, the main thing about Luer-lock dispensing needles is that between the gauge sizes available and the changes in orifice diameters because of wall thickness an exact match between gas accelerator and burner can be made. This will allow the long gas tubes to be deleted from jet ejector burners. I like compactness in a burner.

MP, When it comes to installing burners in a gas forge, they are interchangeable, so nobody says you need to build one of my burners, to begin with; not even me. The burners being sold on eBay at present are bargain priced and work reasonably well; there are many other choices as well. You don't have to build a Mikey burner to get your money's worth out of the book. Life is about choices; therefore options are a very fine thing. Of course, you probably will build one in the end :-)

Two 1/2" burners on a five-gallon forge will give more even heat than one 3/4"; on the other hand, the single burner will heat up most of the forge just fine, and produce less heat loss for gas used; why? Because of the kiln shelf in my design. Leaving the outer inch or two of the forge at a lower heat means less conductive loss via that shelf. Some people use a thin brick and don't extend it outside of the forge, but this makes a weak construction choice. In my next portable gas forge, the kiln shelf will extend even further outside the steel shell. this will be done in order for it to hold a sliding baffle plate, and will be featured on an oval forge, instead of a tube forge.