Mikey98118

Yes, using a MIG contact tip with a smaller orifice allows the gas jet stream to become more powerful, for better air induction. HOWEVER, you can get too much of a good thing, where gas molecules are traveling at too high a velocity to mix properly with inducted air. It's better to just follow the inventor's instructions in the first place. The most extreme example I've seen is a canister mounted propane torch with a standard shaped gas orifice around .004"; it uses full cylinder pressure, which averages 150 PSIG, and works wonderfully...until that tiny hole plugs up with waxes and tar build up from the propane...

You'd be better off paying a $139 for the Devil Forge version (less money and a better burner design). Then look up my comments on round kiln shelves used as exterior baffles for that wide open forge front, and comments on controlling secondary air induction. You'll save a lot of propane ($$$); enough to pay for the forge in a year. Yes, even in a tiny forge like those.

Cornell did post it as a PDF. I think the thread is " something, something, 3/8" burner"

Dave writes: "My reasoning for heavy wall pipe is simple.......I also farm and have a farm shop where I do all my dirty work which is where the forge will be located, during the busy seasons of spring summer and fall there is about 100% chance of something big being placed on top of anything not being used that day which I'm afraid would crush a paint can or stove pipe or such so big pipe I think is better." On the other hand the typical homemade forge or casting furnace is light and highly portable; as in store under the workbench when not in use. I understand the urge to protect sensitive equipment in a shop environment, but all a monstrously thick shell will protect is...the shell; it can't prevent the refractory layers from damage if your forge is knocked on the floor, nor protect the burner, valves and piping, which are all external. So the best plan is to store this equipment out of harms way when not in use. Try stainless steel chimney pipe; it comes in several diameters. My first forge was patterned after Ron Riel's Mini-forge, which is made from a two gallon Freon cylinder (this size and shape cylinder is also used for helium tanks, so check with HVAC companies and balloon supply sources for an empty). I changed some of his building methods and used a five gallon propane cylinder in my book for three different pieces of equipment; one of them being a multi-hole glass and metal furnace. Ironically this latter piece of equipment turned out to be a popular item for builders, but they changed the furnace size back to two-gallon cylinders, which also became a favorite size for blade smithing. Both sizes come with a wall thickness which is just about perfect for the size forge they are used on. Gas cylinders and small air tanks have rounded corners and are completely enclosed. They are high strength to weight shell choices. Plus, you can look on the Riel Burner Pages to find detailed instructions for his forge, or Google Gas Burners for Forges, Furnaces, & Kilns PDF to find mine online; I'd suggest looking up both of them, to get yourself a more solid idea of what you want to build, and how. You also need to keep on reading these threads to find updates to that knowledge. For instance hand held rotary tools have replaced 4-1/2" angle grinders, and 3" 280 watt angle grinder/rotary tools trump both of the other choices.

Sorry to say that Frosty appears to have gotten one of his facts wrong: I'm almost sure that Klingons don't use toilet paper

KWJ, To begin with the pipe fitting on the burner's rear, was an EXCELLENT choice; both for size and for shape: The front opening on your forge is way large, but using stacked bricks or a kiln shelf with a much smaller opening cut in it (just enough to pass stock through) will up your internal temps and protect you from dragon's breath. Before permanently placing the bricks or kiln shelf in position, move this external baffle closer, and then further away from the forge opening to ascertain how much space between them is optimal. Paint the forge interior with ITC-100 or a homemade high emissive coating, along with the side of your baffle plate that faces the forge, and the next photo you take should show a yellow forge interior. General Google, As to forge size, I think you would be happier with either a two gallon Freon bottle tunnel forge heated by two 1/2" burners, or a five gallon equivalent size oval forge heated by a 3/4" burner. if you don't want to build a brick pile forge...at first

And then, we have flames from ribbon burners, which completely change the ol ball game; I like that

Buzzkill, Never back off because the other guy wrote a book, has expert standing, or even a PHD. Let your facts stand tall or fall on their merit, and don't be over impressed with anyone else. I have been thinking about, designing, and running burners and heating equipment for sixteen years, and am still learning obvious things I've overlooked! When Gas Burners hit the book shelves, people on my groups lost all their precious disrespect and healthy skepticism. I had to start using my wife's pet name for me (Mikey) or lose all my antagonists; a terrible fate! Listen to Charles; he has it right. So, don't drive me to extremes. Mikey was plenty bad enough!

Frosty, What is good about bubble alumina refractories is they are all thigh temperature, what was bad when I last looked is their expense. As you've intimated more than once " everything has its up sides and down sides" I always start out all revved up about high tech products, but as often as not the realities of the wallet, are like a bucket of cold water Would love to see photos of an updraft forge; its one of the many things I've wanted to explore. But there are only so many hours in a day...

After 45 years of exposure to welding/burning fumes and silca dust from grinding and friction sawing, I AM the canary in the mine shaft." So, my advice to newbies is on the paranoid side Follow every safety rule, and you probably won't get hurt. Think through every move, and what might go wrong, before you pick up a tool. Avoid breathing anything other than clean air into you lungs. Wash hands and face before eating, and don't eat in your work area. Have nothing to do with asbestos. And did I mention, have nothing to do with asbestos?

The computer fans are delicate and easily overheated (also easily and cheaply replaced, but what fun is that?). I prefer to advise people to set the burners up to be easily removable at shut down, or else to aim them upward. On the other hand, people will go and do what they want, and that's fine too :-) You have to remember that I can play around with ideas as just another member of this group, but anything I write in a for-profit book becomes lawyer bait.

When you move this kind of flame nozzle outward, the flame softens, when you move it back toward the mixing tube edge you harden the flame; move it far enough forward and you not only get two flame envelopes but you can even soften the flame to reducing. Move it back far enough and you get a leaner and leaner oxygen rich flame, until it blows out completely. The effects on the flame are much stronger than the effects of gas jet spacing. Consider nozzle overhang to be the crude setting and nozzle spacing to find the "sweet spot" a further refinement of that crude setting.

Yes, varying the amount of overhang in straight-tube-and-spacer-ring burner nozzles has a huge effect on the flame, since, in effect, it is quite similar to changing the amount of taper in a flared nozzle. As to your other comments, we is "going where angels fear to tread" now. Or to use a Star Trek term, you are now about to enter the Undiscovered Country, and your answers can only be found in a lot more research; at this point old Dr. Frankenburner is quite sensibly hiding under the table and waiting for some other victim to take on that challenge Not all of my burners need choking at start up; some don't and others do. Since they are hand built, such differences aren't predictable, and since a choke must be installed to prevent overheating the burner from chimney affect, at shut down. I never tried to run that oddity down.

Also, look up the section on burner ports in the 3/8" burner thread; if your burner ports aren't sealed your in for a shock. Also, if your burner ports are sealed with old fashioned burners, you could be in for a different kind of shock (a worse one).

Yes, trace amounts of CO is a big deal. It may take a lot of CO exposure to kill a human, but continuing exposure to even minor CO sources causes poor health. What CO does when inhaled is to enter red blood cells, replacing the oxygen they would normally absorb from the lungs. Unlike Co2, carbon monoxide cannot be expelled from red blood cells afterward, in the natural breathing cycle of oxygen in and carbon dioxide out. Carbon monoxide stays in the cell until that cell dies and is replaced up to three months later. So, long term exposure to very small amounts of CO can be pretty devastating to your health.

Since I'm ignorant of how to start a new thread going on IFI, the next subject can start here: So, once you build one of these burners (or any other burner) you'll want to install it in a forge or furnace, which brings us to burner ports. Some people just drill a hole in the steel shell and form a hole in the refractory, but this doesn't provide support for the burner or any way to fine tune its aim within the equipment, so others attach a short length of pipe or heavy wall tube and use six thumb screws, in two rows of three screws each, to trap and aim the burner. So much for the obvious. Now let's discuss control of secondary air, and cooling of the burner. Even single combustion wave burners can benefit from external cooling air, if the burners penetrate extra thick refractory and insulating layers (more than 2") or are vary small 1/4" or less, because internal cooling from the cold incoming propane could be overcome during very long heats, under these conditions. Most burners have at least primary and secondary flame envelopes, and builders deliberately leave their burner ports unsealed, because secondary air induction (now powered by the flame) is needed for complete combustion. Unfortunately, this nearly always leads to an overabundance of a good thing, because the flame becomes an even more powerful induction "motor" than a burner's gas jet makes. It takes energy to heat air, so extra secondary air becomes a drag on performance within the equipment; typically a 20% heat reduction (got your attention now, don't I). Fortunately, we don't have an if/or choice to make. It is just as easy to control incoming air through the burner port as incoming air through the burner. First, add another choke near the end of the burner port's tube; you can even make this one, a revolving choke, since turbulence here has no effect on the flame. Next, mount a washer brazed to a ring with thumb screw on the burner; once the burner is installed, it can be slid up against the pipe's end to seal the port. Is this more work? Obviously; should you expend the additional effort? Also obviously. But what about single combustion wave burners? Better to have a way to cool down the burner when needed, than to depend on luck. If your burner suddenly starts back firing you won't care about temporarily losing some furnace efficiency, so use the same burner port changes for them too. Also if a Mikey burner isn't perfectly made, and perfectly tuned, you will need a very little bit of secondary air for complete comustion in a forge or casting furnace; better to have it than risk even trace amounts of carbon monoxide in your shop.

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?