Mikey98118

That would be "compelling; more coffee needed :-)

Neither is there any point in trying to install a point of one of the Vortex burners in order to seal it against chimney effects, since the plastic fan could not withstand the temperature increases that can happen with all metal burners are expected to, once the forge is shut down anyway; this means that either the burner must be removed every time the forge is shut off, or the burner(s) need to be installed upward facing. Those who have questions need to ask them. Remember that "the only stupid question is the one you don't ask." Revolving chokes are problematic because when they are partially closed over slots or holes they completely change air opening shapes, creating so much more turbulence that the burner can be destabilized; they cause trouble even on rectangular openings, because they change the shape of the opening too much, creating unexpected performance changes, which don't happen with a sliding choke; such changes can be accounted for, but they increase the learning curve for tuning a burner. Why would anyone go there, without a comelling reason to?

Frosty, There are no chokes on vortex burners, since the air stream can be "tuned" via fan speed, to match perfectly with increases and decreases in gas feed and flame nozzle diameters. All my tube burners have sliding chokes; I tried revolving chokes, but they are problematic.

These two burners are part of the Gas Burners for Forges, Furnaces, & Kilns book update, so you guys don't have to buy the updated version to stay current, let alone wait for it to hit the book shelves. These are notes; not the finished chapters, so photos and drawings are yet to be posted, but you can corner the author and demand clarifications.

I wouldn't be surprised to see that flare work out pretty well; if not, it will be simple for you to try different sidameters of tube in it to find the ideal size; then you could just cut two or three of these "inserts" since the flame wear is all internal; this would allow you to stay with tha very nice screw on flare.

Existing tin cans make nice cheap furnace shells, with built in bottoms, which makes them pretty irresistible for first time builders of small furnaces. When someone mentions making a shell from light sheet metal and pop riveting it together for more convenient diameters, most of us just shrug off the suggestion: I certainly did. /But recently I've stumbled across double wall chimney inserts that are filled with...you guessed it; ceramic fiber. Naturally they are too expensive to tempt us, but they got me to thinking... two different diameters of sheet metal pop riveted together could be filled with Perlite that is glued together with either rigidizer or sodium silicate, making a highly insulating and quite rigid furnace shell for a minor monetary output. And since such cylinders can be made larger diameter than the usual shell sources, they could also contain an extra layer of insulation and still have plenty of room left inside for hot-face and insulation layers. Of course the builder doesn't need to use a tubular shape; this kind of shell would also lend itself nicely to oval body forges...

Charles, By the way, thank you for the most enlightening compliment I've ever received. "...to go with a very active mind." Lot of food for thought there...

Frosty, I just wrote out a full page reply to your questions, and this site not only won't accept them, but won't even let me submit them one or two paragraphs at a time. My URL is michael.a.porter at comcast.net mail me yours and I can at least mail your answers to you at home, since I'm being muzzled on this group; something I won't tolerate much longer.

I've tried several times to paste my 3/8" burner chapter on this site, and it doesn't take; what now?

Frosty, I see no stuck foot problem. First, let's talk burner versus torch. Manufacturers and dealers usually call anything running out in the open air a torch, so I could get away with calling all my burners hand torches, since they are all tested for performance in the open air, and work well as hand torches. But they are all designed to be primarily used in heating equipment, so it is less confusing to call them burners, whether hand held, or installed. Theoretically, we are talking about an all primary combustion zone torch/burner. However, the burners must be built correctly, and then carefully tuned to make that flame. Most readers can't resist "doing things their own way; just some 'minor' changes, you know?" Then too, an even larger percentage of readers don't follow directions about tuning the burners correctly, which begins with distance of the gas jet to the entrance of the mixing tube opening (; once that is done, the overhang on the flame nozzle is CRITICAL to burner performance, especially if the operator desires complete primary flame combustion. Note: I called the elongated gas jets n my first book" accelerators" for good reason , but gas jet is the accepted term, and the difference they make is now accepted far and wide, so "gas jets" they are from now on. If these two parameters are met. complete combustion from a neutral primary flame will result. In the real world this rarely happens, so I'm used to seeing a wisp of secondary flame most of the time. As a hot rodding mad scientist monomaniac, this disturbs me, but it makes no practical difference at all; especially when these burners are installed in heating equipment, because their flames actually change and improve inside a forge or furnace; you can see them elongate and their outline becomes smooth, instead of slightly jagged, as they appear in the open air. I believe it is back-pressure from the equipment the burners are installed within that improves the flames, and although I had always assumed the refractory lining absorbing sound was the reason they ran so much quieter inside heating equipment, it just now occurs to me that the change in the flame is a more likely reason for this. Burner noise is created by turbulant flame; the smoother the flame the quieter it is. I never tumbled to that obvious conclusion before, because I hadn't experienced the drop in flame noise from Vortex burners, which make much smoother turbulent flames than my tube burners produce. To explain my claim of quieter burners, we only have to remember that laminar flames, whether from air-fuel Bunsen burners, or from torches make so little noise that the sounds we associate with either tool are simply the sounds of gas flowing into the mixing tube(s); sounds which are normally drowned out by the flame noise from turbulent burner flames. Don't you just love the obvious? Conclusions, floating around right under your nose can take years to be sniffed out; this one lay dormant for a decade and a half! That should read oxy-fuel torches I think most readers falsely assume that tuning is done with the sliding choke. What the choke is really for is cold start ups, when the flame nozzle isn't heated enough to assist with fuel combustion, and for running the burner rich at times, which otherwise couldn't be done with one of my burners.

I just looked up metalbestos pipe and a whole raft of stuff I've never seen before is on the web now, including oval shaped chimney pipe, and ceramic fiber insulated pipe.

Frosty writes: "Another gas forge I really like is a SS stove pipe shell. The stuff is a little expensive but not unreasonable, you don't need special tools to work it: ruler, red pencil, tin snips, drill, bits and a pop rivet gun is your tool kit. Everything else is off the shelf. One last handy little bit about stainless steel you'll like Mike, you're as selfish about heat you've spent good money to generate as I am. Stainless steel has a high IR albedo. It reflects heat." I thought about using one of those, along with a 1" inner layer of ceramic fiber blanket (at the rate my burners eat up stainless steel flame nozzles, I wouldn't want to risk exposing a thin inner liner of stainless to flame impingement from one of them). And since we've both mentioned them, we should warn people to wear at least a double string dust mask when working on the pipe, and thoroughly vacuum the work area afterward, since it's lined with asbestos. But, I think most people would not want to spend the money for such a fancy shell with so many tin cans in the world; wouldn't stop me though. Yes, that would make a nice Formula One piece of heating equipment...

Well, now I've got a problem. This site won't accept my attempts to post my chapter notes for the 3/8" burner. How do I work around this little glitch?

Not if it's a naturally aspirated burner; they have long turn-down ranges.

I'm a little torn, between advising newbies to start with a brick pile forge, which certainly has endless virtues, and advising them to start with a miniature forge coffee-can or two gallon refrigerant cylinder sized, which is super portable and easily stowed beneath a workbench, and will always find use even after they decide on what their personal version of the "perfect forge" is. I built both and still can't decide, which is better; maybe it just comes down to what a guy thinks is the most nifty? I think for some of us its like collecting cars; more a case of greed than common sense

Venturi, It is hard to tell for sure from the photo, but that looks like an armored cable covered gas hose leading to your burner; I heartily approve of that stuff used that way.

Frosty, You also asked about air opening position and size. I made my slots about 40% larger (when the area of all of them was added together) than the area of the flame nozzle; this turned out to be unnecessary, which became obvious when the burners were tuned As the choke was opened on these burners it would reach a point of maximum efficiency before coming even with the front of the air openings. I was being very conservative in my construction methods, because I wanted "some of everything to spare" when readers built my burners, which brings us to your other question... All air openings were laid out in odd numbers (3, 5, so that they were never positioned opposite of one another. so as to insure that each entering air stream was less likely to interfere with another stream; I thought that necessarry becuase spin was imparted to the air streams. I also used more openings than needed, to ensure smooth operation (longer thenner openings tone down the performance a bit more than shorter wider openings do). Of course the optimal number of openings on any jet-ejector burner is three, but I was a lot less concerned with maximum performance than in ensuring maximum stability in an entirely new burner design. After years of retrospection, I would not recommend more than three air openings on these burners; but that is now; not then. The difference between what we picture in the mind's eye and what happens is the reason for experiment, but looking back on it all, I am still "taking some of my mental pictures" on faith; I did enough experiments to design good burners, but not enough to prove everything I 'know' on the subject. After two years the publisher wanted a finished book. I probably will run smoke test, etc. on the Vortex burners, though.

Okay all, I will post my book notes on the 3/8" burner, which can be used in a Coffee-can size furnace by turning it down most of the way, and is quite capable of heating a properly built Freon cylinder forge, to yellow-white heat. This chapter is text only; there are no drawings or photos in it yet, but those of us who are involved in building these burners can post photos, and relate our experiences as we go. And, of course, you all can corner the author and insist on further explanations as we go. Lets keep it all on this thread for now, and when we are finished with the subject, it can be given its own thread; maybe along with better instructions on constructing miniature forges. Forging Carver, It would be silly to break apart your forge's filler at this point; better to build your burner and use it to test out whether or not the burner port is too close, instead. Also your port pipe isn't placed at the right angle to get good swirl, which means the combusted gases will exit the forge faster; that can cost you as much fuel as poor insulation This also gives you something to use while you collect the materials to insulate the forge with the correct way, next try. This is also your opportunity to place a high alumina kiln shelf in front of the forge opening at a variable distance, and use it as a baffle plate. You've already paid in labor to put that insulation in it, so put it to some good use as a test bed, before breaking it down.

Frosty, Well, that gets us back to brick pile forges again; after all, I can't think of any other forge that would allow someone to play around with size, shape, and completely different burner systems. So, to the list of their virtues we can logically claim they are the best (self) teaching tools

Harry, My answer was expert, but also flippant; so I apologize for that. Adding charcoal won't just create a reducing atmosphere in the forge; it will create a carbonizing atmosphere, which is no big deal, unless you've gone to the expense and trouble to paint a high-emissive coating in it, in which case that nice rich carbon source will do a wonderful job if covering it up. I learned this lesson the hard way by using a propane additive that was meant to be used in an oxy-fuel flame; not air-fuel. Thereafter, I had lousy performance for the several heats it took to completely burn that coating away (ITC-100 is too delicate to be wiped clean). Also, all you have to do in order to know your flame isn't oxidizing is look for any trace whatsoever of secondary flame. So long as you can see the nearest trace, than your flame is still reducing or neutral; not oxidizing.

Probably; but remember you'll be working right next to a forge, so it probably won't be all that cold.

Frosty has it right

Frosty asked "Is Rex still machining his burners from billet?" I haven't communicated with him in nearly fourteen years, and have no interest in his problems. You know those little curled arrow symbols at the back end of airplane wings in drawings of what happens to air flow over one of them? Imagine for a minute that if you can get that much drag from what, for all practical purposes is a knife edge, with the air running past it in parallel on the bottom side, and at a very close angle on the top side, how much more drag you get with air running past an edge at close to right angles. How much drag is in direct proportion to how fast the air flow is, but naturally aspirated burners only use tiny forces to induce air flow, so a little bit of drag goes a loooooong way in interfering with burner operation. Round edges produce more drag than straight edges, and a row of holes has a whole lot of round edges. So, you would naturally assume that reducing those round edges down from many to just two in a slot shaped opening would get rid of all that drag, yes? NO; it gets rid of a lot of drag, but one of those round edges is right at the mixing tube entrance and just forward of the gas jet; the amount of drag a round edge creates there is a REAL BIG DEAL! Even at the back of the air opening you can see a definite performance difference between straight edge and curved. So, I cut out rectangular air openings, but didn't get as big of a performance leap as expected...until I went the extra mile and beveled the forward and rear faces of those rectangles to knife edges. it was like driving down the road, and finally remembering to release the safety brake; big difference. Orange and red streaks are not uncommon in high speed flames coming out of a stainless steel nozzle. I had occasionally noticed them in one of my burners, but paid them no mind, until a couple of glass artists posted a question about it on one of the casting groups; I invited them to send me their burners (with return postage prepaid). The burners were correctly built and worked beautifully, but their flames made a lot of red and orange streaks. The flame nozzles were also highly reflective. They had used #304 stainless. On a hunch, I replaced the nozzles with #316, and presto; no more streaks. I will have to visit the Hybridburners.com site and look at the flames; that's what I get for throwing in an out of date memory...suppose we need to refresh them every decade or so It is fine that you're interested in burner mechanics, but just remember that your burner has probably been built by more blacksmiths than all of mine. It takes about eight hours and a lot more money to build a high speed tube burner, or over $200 to buy one; that can be discouraging for people just starting out. I'd much rather they built an easy to construct burner and come play in the pool. I get to lure more people down to the deep end that way

Actually, a bean can forge would use a 1/4" burner. A 3/8" burner would only work even in a coffee can forge by turning it down most of the way. There is something to be said for using some kinds of jewelry torches in miniature forges, but you must be careful to keep them from overheating. Forging Carver, If you want to get hold of a two gallon size helium cylinder or non-refillable refrigerant cylinder and build a proper knife forge, I will post instructions on this forum for building my latest (generation six) high speed tube burner.

I suppose people can find some benefit in almost anything, but if you should ask whether or not there is any practical benefit the answer would be no.