Mikey98118

I believe this is the case. The air flow doesn't pass the jet lengthwise and largely intakes down stream from it so whatever turbulence the jet imparts is minimal. Frosty The Lucky. I agree; since the air doesn't pass along side the tip, tapering would be pointless; don't bother.

Also, high mass refractories are more given to cracking than some semi-insulted types. I think the heavier castable refractories (ex. 140 Lbs to the cubic foot) were developed to be the most resistance to attack from molten glass, etc., rather than for general toughness. That would be insulated, not "insulted" :-) That would be resistant, not "resistance" That's it; time for a cup of coffee!

Wayne's website is a good one. I have built many casting furnaces using Kaolite 3000, and find it to be hard wearing, and and quick to heat up; it also requires no kiln shelf, as it's already resistant to flux, and will support work pieces just fine. So what's the difference between this kind of construction and straight ceramic fiber? About ten minutes more heating time, if you finish coat it with a high-emissive coating, and if you use a secondary layer of fiber insulation, so that the inner layer of cast refractory isn't thicker than an inch. Such construction can provide a full time working shop with the best blend of heartiness and efficiency in a heating tool. I also agree with his hinged design, something I've pondered doing for years, but never got around to trying; I'm glad Wayne did. The article posted on his site about ribbon burners and how to build them is the best information I've found on the Net thus far. And, I don't think you can find a more reasonable source for purchasing the small amounts of refractory products anyone building a knife forge uses.

Dear Mitch, Your video is quite revealing. In the first place the burner with the smaller flame definitely is partially clogged. At one point it starts to go out as it passes something through the flame; this is what causes the temporary yellowing of that flame. The only question remaining is whether the obstruction was coming out of the mixing tube or through the gas accelerator. You should have look at the MIG tip. take it out, hold it up to a light source, and look for a partial obstruction; such as tar build up. The common cure for tar balls in the gas accelerator is to poke them back out the tip's rear face using a set of torch tip cleaners (about $3 online or from your local welding supplies store). If the tip is clean, look for such an obstruction in the fuel line where it hooks up to the burner or at any point where the feed suddenly narrows. Unfortunately, this isn't your only problem. Due to design flaws your burners are putting out weak reducing flames, which is the reason they are followed by those large purple secondary flames. In order to burn those secondary flames you will need to leave the burner ports unsealed, which will pull in more secondary air than your burners need-- in effect, super-cooling the forge interior--which is very wasteful, and will likely prevent you from reaching billet welding temperatures with those weak flames. The quickest solution for your weak flames is to change out the reducer fittings for the type that are used on so called modified side-arm burners. The kind of side-arm burners you show are the original design, which I first tried in 1999, after seeing them featured on Ron Riel's burner pages; they never worked worth spit. A Southern blacksmith (Kentucky?) first used a better shaped fitting for air induction and came up with a pretty nice flame on his burner designs. To give fair warning you should know that I'm kind of the hot-rod maniac about burners. So, while I don't personally recommend his burners , it is only because I want to scream down the street with fire shooting out of my rod's tail pipes. If you just want a burner to ride back and forth to work and take your family out for summer drives...his burners are fine and dandy. Forced air forges are not the hottest/best forge designs; "there ain't no such animal"!!! The best forge design for the task(s) you want to complete is whatever it turns out to be, just as there is no such thing as the very best burner design, or the ultimate forge hammer. Forced air versus naturally aspirated burners was a debate that was raging when I first started building forges sixteen years ago, and it's still nothing more than a "my dog's better than your dog" debate today. People get used to working with a certain tool, and if that tool does a good job for them, they tend to personalize their view of it. But, the truth is that a forge designed to get the job done, while meeting your other goals (such as fuel thriftiness, or quick heating times; compactness, and/or portability versus hardiness); overcoming some back pressure or working outside in winds; even heated interior, or spot heating for best efficiency on small areas; in other words prodycubg tge best results for your needs. The other man may have very different priorities. Love your dog, but don't kickdhls his pooch around. There is another trap to avoid in tool design; when a tool serves well, we may get blinded by that and refuse to move on, once we outgrow it. I started out building naturally aspirated propane burners because I had recently worked in a very large and drafty building that was warmed up quite effectively by one five-gallon size fan-blown gas forge. Thinking about what it would be like living with this (in effect) monster shop heater in my little garage in the summer was the stuff of nightmares! So, I learned to make very compact efficient flames in very compact efficient heating equipment, and "lived happily ever after" for about twelve years. But, there were signs of trouble in paradise...my lovely burners would melt down the heating chambers of chip forges, and would melt the stainless steel flame nozzles right off the ends of burners if not placed just right in heating equipment. Obviously, very hot compact flames were Jim Dandy for most stuff, but not for everything. So, I decided to play nice and pet the other guy's Fido. Thus started burner book two, on fan-blown burner systems, which got interrupted by burner book three on Vortex burners; this all seems pretty rambling, but the point is, I had to abandon my own prejudices to discover Vortex burners, and furthermore, the book on ordinary fan-blown burners still needs to be written, because fan-blown burners do some tasks better than any other kind.

Latticino, Yeah, Giberson practically invented home brewed hot glass work, but I had three problems with his burner heads: (1) They cost a lot of money (2) They are vulnerable to damage from rapid thermal cycling; this is no problem for day tanks, but is a real sticking point for metal working hobbies. (3) They are not supposed to be used in a sealed port, which will cost a lot heat lost from uncontrolled secondary air ietrainment. The ribbon burners have none of these weaknesses, so I'm thinking about trying out a cast refractory burner head mated to a fan-blown ransom type burner, and also to a Vortex burner (just to be thorough).

Frosty, I don't think you and Ron so much drifted apart as that he got very involved in his web pages, and of course later he darn near got swallowed whole by one set of troubles on top of another. First he was required to re-certify when his teaching credentials were threatened, and then about a six month siege of pneumonia. He and I had a falling out about then over Rex Price, and quit speaking to each other. Later, I heard he had a series of heart attacks. Talk about being retired with a thump! Like me, Ron did seem to be in love with tools...but he spoke well of you when I knew him, and he was definitely impressed with your "T" burner. He used to hint about it like it was classified material. You'll be pleased to know he never discussed a single detail of its construction with me though. You should try to get back in touch with him, now that both of you have more time. Yes, Charles: My absolute favorite thing is to hand somebody an idea that excites him so much he can't sleep. When I was Writing Gas Burners ideas would wake me up at two or three in the morning and not let me rest until they were written down. Passing that excitement on to others feels sublime. And of course there is that magic moment when a student lights up his first hotrod of a burner, and I can see his own inner mad scientist gloating and making plans; yummy! 1 Frosty, after some consideration it seems to me that a mixing tube that is tapered, could be the naturally aspirated burner fan's answer to fan-blown ribbon burners, if they get too uppity about them you may have to complete your experiments, just to keep the competition going :-)

Alas, with "scratch arc" TIG for shipboard small pipes, gas welding is nearly gone. I loved doing it, though, and am sorry for that little bit of progress. BTW, you are sooo right about an inspector needing to know, first hand, how the weldor goes about doing things; they didn't at Boeing, and some of us played with them shamelessly

Making reasonably priced highly efficient IR coatings is easy. Making a tough highly insulating IR coating is much more worthwhile, though. If ITC coatings were a dollar a pint, they still wouldn't do anything to toughen up insulating firebricks. But the thicker your "kiln wash" the tougher the brick will become. I think you're onto something important. Helpful hint: high alumina refractory is the next most insulating substance after zirconia, and you can order high alumina refractory in small amount on the Net.

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, I more agree than disagree with your viewpoint. And, at any rate try not to let the mad scientist part run away with the rest of me, lest I can no longer lure victims down to the deep end of the pool Doctor Frankenburner

I did quite a bit of research along these lines for a book about crucibles; one of the three that the hacker destroyed. So before I forget the facts completely: (1) Untreated zirconium oxide changes its crystaline structure at about 1600 F as it passes beyond it, and again during cooling below it; this changes its size, crumbling any hard matrix it's part of. stabilized zirconium oxide used to cost twice what the plain oxide does; nowadays, it only costs about one-third more. And there are three different elements used as stabilizing agents. (2) You want to choose very fine zirconium oxide powder to make emissive coatings with, in order to get its famous heat repelling benefits. Also, really fine powder is colloidal, and so will spreads much better on a hot-face surfaces. (3) In the nineteen-sixties there were government sponsored tests made of zirconium coatings for heat shielding, and it was discovered that phosphoric acid was very useful for keeping zirconium particles "glued" to heating surfaces, because the first time its heated it polymerizes, and thereafter is sticky when heated, and vitreous when cold. Phosphoric acid also stays nicely suspended in water...now, I'm not suggesting that you can save tons of money and end up with a better product this way...you all should see that on your own. (4) Zirconium silicate is a man made material that's becoming ever more popular in castable refractory mixes, and as part of crucible formulas, because it doesn't break down under crystalline change or expose other materials in the matrix to physical stress, and the silica content is a standard binding ingredient in refractory formulas anyway. "What you describe about zirconia absorbing then re-radiating is the description of a reverberatory furnace. The liner get's hot and the stock is heated by radiated IR." Yes, but deliberately preserving and employing IR radiation should be a part of all forges and furnaces; this is why I keep harping on the use of exterior baffle plates on heating equipment. People think of heat loss from escaping combustion products through exhaust ports, which cannot be prevented, and fail utterly to see the equally great loss through radiated heat through those same ports, which is easily preventable!!!

Frosty has it right, But you can also use MIG tips the next size up, and insert capillary tube in them, in order to come up with the orifice you want without drilling, there are many ways to get around drilling in copper; all of them are better than drilling.

I liked the vinegar tip; it opens up whole new possibilities for using electrical conduit and fittings without exposure to zinc fumes

Isn't there also an SA knife makers guild? I believe they had a big conference/knife show in Los Vegas five or six years back.

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.

Frosty, To be fair, eight diameters always makes a good starting point during R&D, and most people would probably be perfectly happy with it as far as results go on most burners.

Kyle, The first problem with your burner is that you used a standard "T" pipe fitting instead of a Ward brand reducing "T"; you can order them from Larry Zoeller forge. The second problem is that you screwed a pipe fitting onto the burner, instead of building or buying a flared stainless steel flame nozzle; also available from Larry Zoeller Forge. Larry pioneered the popular modified side-arm burner. Make these simple changes and your burner should work fine. Kyle, Forge building questions are being debated elsewhere in these forums. If you don't want to read Gas Burners for Forges, Furnaces, & Kilns, then look under gas burners on youtube. In that section a guy shows a very creditable video on how to build a furnace from an old propane tank; his methods are a liittle different from mine, but I like them well enough.

Every naturally aspirated burner has a "turn down range; this consists of the amount of input pressure to the gas jet between the maximum jpressure, above which the flame blows clear off the burner, and the minimum input pressure, below which the flame becomes erratic and finally burns back into the mixing tube. These are pretty straight forward adjustments and easily gotten used to. But, most NA burners need to be choked back until they warm up; then the choke sleeve or choke plate can be opened all the way. This is such a basic problem that most of us forget it's a real surprise for newbies.

jcornell jcornell, I like your idea of a "home brew mix of zircopax and kaolin for a tough hard high IR "reflector" coating better than anything else I've heard. Zircopax is basically zirconium silicate (probably with a temporary binder ingredient added). The point of zirconium silicate instead of zirconium oxide is that it amounts to a form of stabilized zirconium (which is otherwise expensive) silicon is a common ingredient used to help bind (and vitrify) refractory mixtures together, and is fairly tough and heat resistant. Kaolin clay is another inexpensive tough heat resistant binder ingredient in refractory mixtures; together they should produce an ideal high emissivity coating and fiber sealant. What proportions do you use?

I liked both viewpoints; especially as hot-face coatings are an important subject for me at present. I'm still chewing on the information. And I can almost see Charlotte wondering why I'd feel hesitant on this subject. Well, it ain't so straightforward as running a hard coating over rigidized ceramic blanket after all, because of stabilized zirconium oxide powder, and of zirconium silicate. It turns out that so called infrared "reflector" coatings are actually high emissivity coatings. The way a product liike ITC-100 actually works is that the zirconium content is highly absorbent of radiant energy, which it then re-radiates it in all directions. With a thin coating (under two millimeters) there is a net gain in heat absorption, along with a net gain in heat radiation, and thus it is used on some exterior crucible surfaces. But, with thicker layers (five millimeters and up) the net effect is re-radiation along with very efficient insulation from heat gain, and so these are used on interior equipment surfaces to boost "reflection" of radiant energy from equipment hot-faces. Confusing isn't it? A very thin coating of zirconium on the outside of a crucible increases heat transfer through its wall, but a thicker coating on equipment walls acts as a highly efficient heat "reflector." So, why would anyone use something this expensive for heat "reflection" instead of an extra layer of insulation? Partly because elevated radiant energy levels within heating equipment do heating work, and passive insulation does not, and partly because every bit of heat turned back at the surface layer of the hot-face, helps to spare the wall material from exposure to elevated heat levels, which is very important for products like ceramic fiber blanket and board. But the kicker is that the efficiency of insulating products falls off at elevated temperatures, while the efficiency of emissivity coatings increases at higher heat levels. Zirconium silicate is used as an ingredient in refractories for this very purpose. And so we see that comparatively thin refractory layers that are rich in it can do an almighty lot to increase both the efficiency and the life expectancy of a forge. Whew, them's hard sayins! 1

From the very beginning I did all my testing out in the open air, because I found that any naturally aspirated burner that works well in open air only works all the better after being placed in a forge or furnace. So, discovering the ability of these burners to be used as heating torches was a by product of testing procedures. During the years since publication canister mounted air/propane torches have improved immensely, but they still can't compete with a properly built and tuned homemade burner.

Okay, If we are talking about tapered mixing tubes, then I would think that 12:1 ratio might be more useful than 8 diameters, but on straight tube or pipe, a rule of thumb consisting of x many diameters for mixing tube length will end up variable according to mixture feed speed, internal pressure, and whether or not internal vanes are installed. So, exactly how many diameters of length are optimal is going to change for every burner design. Fourteen diameters are needed on my vortex burners only to deliberately provide more friction so as to slow down swirl in the exiting flame. But installing internal vanes in order to shorten mixing tube length would add another layer of complexity, which I don't want to introduce to "the discussion" at this stage of the game.

Charlotte, You stated that "MAPP's real strength was in forehand horizontal welding." I can only picture forward flame welding in the horizontal position as appropriate for for either a root pass, or multiple bead finish passes; when I wanted good single bead shape on a finish pass I welded back hand. Give with the details; us ex welders wanna know!

You've probably already read up some about brick pile forges on these forums; they are an especially good option for people who don't have any firm ideas on what shape or size they want their gas forge to be. On the other hand they aren't exactly cheap to build. Also, if you want the forge to be portable, than a light steel shell is pretty much essential. One of the handiest things to use for the forge shell on a knife maker's forge is a two gallon non refillable refrigerant cylinder, because its wall thickness is ideal, giving the maximum strength to weight ratio you could desire for that size of tunnel forge. A five gallon (twenty pound) LPG (propane or butane) cylinder is the most commonly used item for tunnel (cylindrical shaped) forges, but a five gallon paint can will do just fine. Don't use a popcorn can; their wall thickness is too thin. And don't let anyone kid you that a certain minimum strength in the shell isn't needed; it is. You will probably be suspending a high alumina kiln shelf from that shell, and bolting legs to it, along with a pipe to hold the burner. It also needs to be strong enough to prevent damage to insulating fire brick and/or rigidized ceramic fiber blanket and brittle hot-face coatings. If you choose to use a five gallon paint can there will even be room to install an outer layer of perllite glued together with water glass, which is also both rigid and delicate, just like rigidized ceramic blanket (but a LOT cheaper).

Frosty's evaluation is dead on the money, and I encourage you to make that flare.