Burners 101

[Mikey98118]

Occlusions in the gas orifice

Why is it important to screw the gas orifice onto your burner's gas line? Construction debris must be thoroughly cleaned from your burner’s gas orifice during construction. But, after a short time, any debris in a gas hose, or lodged in valves and/or regulator will be blown into the burner’s gas orifice. After further time, propane (or LPG fuel mixtures) can leave residues of wax and/or tar in your burner’s gas orifice; especially in the orifice of small burners. How long that takes, depends on the quality of the fuel, and how small that gas orifice is. Whether the flame gets leaner for a while, bent off center, or reducing is just pure chance; it could go through all those stages. However, eventually the burner will be snuffed out, when the obstruction completely blocks off gas flow.

   

Remove the gas orifice and blow air through it in the opposite direction of normal gas flow. If you have no source of compressed air, stuff a wire file from a set of torch tip cleaners through the orifice from the exit clear through its entrance. Poke the orifice one time only. You don’t want the file to start enlarging the orifice. Try to catch the obstruction and have a look at it. Whether you see a little black tar ball, general debris, or the remains of a baby spider will tell you how likely the problem is to recur.

    A friend of mine had his burner shut down after about three weeks of running propane from an especially cheap source through it. A single poke through the burner’s MIG tip with a wire file produced a tiny little black tar ball. A smith in Europe found his gas system, and burner orifice lined with what he described as “ greasy waxy stuff,” after a few months of forge use.  

 

[Mikey98118]

Gas Orifice Sizes

The gas orifice on a naturally aspirated burner must closely match its diameter in relation with the inside diameter of a burner’s mixing tube. On 3/4” and larger burners, this is best accomplished with a MIG contact tip. On burners 3/8” size and smaller, 3D printer nozzles have every advantage over MIG tips (even with capillary tube trapped in them as precise gas orifices); this is because the greatly increased friction of the gas molecules through smaller orifices make it necessary to shorten the length of capillary tubes down to that of printer nozzles. So, in smaller burners, capillary tubing used for gas orifices give little to no advantage, while printer nozzles are cheaper, more easily acquired, and far simpler to employ. Right in the middle of these ranges are 1/2” burners, which can benefit from an exactly correct size and length of capillary tube in a MIG tip, but do nearly as well with a 3D printer nozzle (with far less work and expense).

MK8 Ender 3 extruder nozzles are available through Amazon.com); they have M6x1 metric male thread. The markings on each of these nozzles stands for the orifice diameter in millimeters:

 0.3 (millimeter) is 0.0117” orifice diameter; a good gas orifice size on a 1/8” burner.

0.4 (millimeter) is 0.0156” diameter; a good gas orifice size on a 1/4” burner.

0.5 (millimeter) is 0.0195” diameter; a good gas orifice size on a 3/8” burner.

0.6 (millimeter) is 0.0234” diameter; a possible gas orifice size on a 1/2” burner.

0.7 (millimeter) is 0.0273” orifice diameter; a suitable gas orifice size on a 1/2” burner, but a capillary tube can be tuned for performance by varying its length; thus the right orifice diameter tube can give a little better performance than a printer nozzle.

MIG contact tips come in various sizes, brands, and lengths. You are employing Tweco 14T series tips for various size welding wires; the numbers they are described with are for those wires; not the orifice size of the tips. This tip series, and their lookalikes in other brands are all 1-1/2” long tapered tips, with 1/4-27 thread; the 1/2” long narrowed internal area at the end of each tip is called its “through hole”:

0.023” MIG contact tips are supposed to have 0.030” orifice sizes. But the actual orifice size may be as large as 0.032”. The smaller orifice is barely adequate in a 1/2” burner and the larger orifice is not. A 1” long 0.030” inside diameter capillary tube trapped in a MIG tip will serve quite well.

0.025” tips have a 0.034” orifice. So long as you aren’t sold a 0.023” tip in place of the 0.025” tip, it will work well in a 3/4” burner.

0.035” tips have a 0.044” orifice; they will be a little oxidizing in a 1” burner.

0.040” tips have a 0.048” orifice; it will be a little reducing in a 1” burner.

0.045” tips have a 0.054” orifice; they will be a little oxidizing in a 1-1/4” burner.

0.052” tips have a 0.064” orifice; they will be a little reducing in a 1-1/4” burner.

It is necessary to adjust how close the tip of your gas orifice is to the tube section at the small end of a funnel or pipe reducer fitting (or to the forward ends of air openings on tube burners).

[Mikey98118]

Gas Assemblies for linear N.A. Burners

It has been well established that the gas pipe and whatever MIG contact tip, 3D printer nozzle, or other gas orifice is used, should be centered with, and aimed parallel to the burner’s reducer fitting or funnel; and that must be centered on, and parallel to the mixing tube’s axis, by whatever means is convenient. BUT, the devil is in the details, because how you choose to mount the gas assembly, is your first and best chance, to create an intense burner flame; don't waste it!

    Why such emphases on a “minor” detail? You have an energy budget; it's limited to the air induction that the gas jet creates; this is a naturally aspirated burner's engine. It takes energy to get incoming air moving, and also to change air direction, to create spin. So, starting that directional change at the same point where forward motion begins, will require the least energy from your tiny budget.

    So why not install a high-power fan or compressor fitting at the opening? How much breath is required to blow out a candle? That is about the same amount of excess force—input at the wrong place—needed to blow out a burner flame too. If you want an intense flame, it comes from control and balance—not from blindly pushing incoming air.

    There is another important factor to consider; as with a whirlpool in your bathtub drain, nearly all air motion is going to happen near to the opening’s periphery. No significant air will move down the center of the entrance. So what? So, this tells you just where streamlining matters—and where it doesn’t.

    Mounting a gas assembly has two facets; what is easy and what works best. There will be no "perfect” method to balancing these aspects, because, aside from tooling and skill levels, we all have preferences; mine is for maximum control of the parts being assembled. I have found that we get the best results for the least work, if Murphy’s law is never given a chance to muck anything up.

    Gas assemblies are best mounted on naturally aspirated linear burners, by suspending them in the center holes of fender washers, of up to 2-1/2” diameter, keeping your work at a minimum, by doing only part of the work needed to fashion a mounting plate from scratch. For larger openings than 2-1/2” you must completely fabricate your mounting plate from sheet metal.

    So, why start with sheet metal, or a fender washer to make a mounting plate? Why not braze together separate parts instead? When you begin with a flat surface; all you need do, is avoid bending it, to assure that the gas assembly mounted to it, will remain perpendicular to the air opening, and therefore axially true to the burner’s mixing tube. Fender washers come in various thicknesses, over which you have little control; because they all have 2-1/2” or smaller diameters, that’s okay. But the larger mounting plates you make from sheet metal need a minimum thickness, to ensure that they stay flat while being worked. 0.079” thickness in stainless=steel plate is strong enough to stay flat when being silver brazed to a funnel, but not so thick that it is too difficult to cut, grind, drill, and thread. Use a divider (best) or compass (workable), and a prick punch, to lay out a disc of the same diameter as the flange diameter of the large opening in a funnel. whether you want to silver braze, solder, screw, or glue it in position at the opening.

    Cut a hole in the middle of the disc for your threaded gas tube to screw through. Mark out three equal spaces for ribs between the air openings, using the divider or compass (or just estimate using the flats of a hex nut). Drill small holes between the areas of the ribs and outside the area of the gas tube’s two nuts.

    Remember that there is no significant air flow in this central part of the opening, so don't shortchange yourself on material in this area. The ribs would be fairly narrow if you kept their lines parallel, but that isn't desirable. You want the three ribs narrower at their outer ends, and becoming wider toward the center of your disc, to balance maximum air flow with sufficient material strength.

    A small brass gas tube needs to have exterior thread, run down its exterior, allowing it to move back and forth within a nut, which is silver brazed on the fender washer, or hand cut mounting plate; this allows the gas orifice on its end to be positioned at the perfect distance from the opening of the mixing tube (at the funnel’s far end); this is used for fine tuning burner performance.

    Your burner should be aimed upward, or positioned horizontally through a wall from near the forge ceiling if a box forge, or through the tubular wall toward the bottom of a vertical casting furnace, so that no choke plate is needed. Therefore, the threaded gas tube can be trapped between two nuts on either face of a mounting plate. The nut on the plate’s bottom face is silver brazed to it. The upper nut is used for locking the gas tube firmly in place, and is brazed, soldered, or glued to the gas tube, after all tuning is complete.

[Mikey98118]

Vortex Burner fundamentals

(Advanced linear burners)

    Let’s start by clarifying just what is meant by the term “vortex burner.” Burners that swirl the flames they make are often touted as vortex burners. But causing a flame to swirl happens far too late in the air/fuel mixing process to provide much benefit; used this way, the description is mere hype.

    Vortex is a fluid dynamics term, describing a region where the flow of gas or liquid revolves around an axis line.  The vortices generated on the tailing edge of a plane’s wing just create drag. At the other extreme, a tornado’s funnel is powerful, but only destructive. The gentle current of a bathtub drain effectively employs vortex flow to good purpose, and so should your burner’s air entrance.

    For good combustion, it is necessary for incoming air to mix sufficiently with a burner’s fuel. A swirling motion provides the most mixing for the least drag on your burner’s gas/air mixture flow.  When incoming air passes through a constricting tubular shape (ex. pipe reducer or kitchen funnel), vortex movement is generated, becoming an excellent air/fuel mixing aid. Most successful burners, whether linear or not, create at least some vortex flow. My high-speed tube burners are an exception; they gain swirl from three (fore and aft beveled) rectangular side air entrances,. Nevertheless, if you place a pipe reducer between their air entrances, and a smaller diameter mixing tube, even their performance will be enhanced.

    If most successful burner designs create vortex flow, why bring it up? Because the people who designed those burners, only pictured them as swirling incoming air into a stream of fuel gas, and thought no further. “V” burners, both passive, and fan-induced, showed be deliberately designed to enhance vortex flow, and then to derive maximum benefit from it.   

    Any device that provides lateral air movement at a funnel opening, will increase vortex flow; this includes the opposed air openings on “T” plumbing fixtures, disc shaped choke plates near funnel entrances, or (my favorite) motionless blades in front of a funnel opening. If you strip the impeller blades from a cheap or worn-out axial computer fan, and mount them on a linear gas tube at a burner’s funnel opening, they will significantly increase vortex movement through the funnel, even though they are still, because they start lateral air movement (spin) at or even before the opening’s entrance, rather than within the funnel.

    Installing axial computer fans on linear burners will supercharge vortex flow, but this requires a trickier gas assembly, and an electrical power source. So, it is easier for novices to move from passive to powered “V” burners in stages.

    Some parts used for air openings on naturally aspirated burners also work well with a moving fan, while others do not. However, the limits on shape and sizes imposed for use with moving impeller blades, do not apply to motionless blades; these can be mounted on linear gas tubes (parallel to the burner’s axis) without struggle or worry.  

    Straight or curved wall pipe reducers, kitchen funnels, and other constricting tubular shapes provide convenient ready-made reasonably priced burner openings for incoming air to revolve its way through, and into the burner’s mixing tube; its ever-decreasing spiral path increases its rotational speed, along with its forward velocity (by about one-half of its rotational speed). Also, the faster the incoming air’s rotation the lower the pressure of the air flow through the mixing tube; this is all very good for mixing, but requires the mixing tube to be lengthened enough to stabilize the flame (because friction within the tube slows down the mixture’s swirl and forward velocity, before it exits).

    Or, internal vanes near the tube’s exit can be made to slow air spin, in order to keep the mixing tube’s length shorter. A larger diameter flame retention nozzle can act to break the flow’s exit speed sufficiently. Thus, you would need to exchange your smaller flame retention nozzle, used at lower gas pressures and fan speeds, for a larger one, when running a fan-induced burner full-out.

    The first thing to keep in mind about funnels and other constrictive shapes, is that the greater the ratio between the air opening’s diameter and the mixing tube’s internal diameter, the stronger the vortex.

    Secondly, the shorter the length of the funnel the greater the drop in air pressure it creates at the opening. This drop in the pressure of incoming air isn’t sufficient to create a problem in naturally aspirated burners, but when added to the low-pressure zone created with moving impeller blades, backflow can draw some fuel gas into the fan. Then, the fan’s electrical sparks will ignite the fuel/air mixture.

    So, a maximum 3:1 ratio between entrance diameter to the mixing tube’s internal diameter, becomes the first safety margin with fan-induced burners; another safety margin is provided with sufficient length in the funnel shape, or the addition of a short tube section between the funnel opening and the fan; this has the same effect as a longer funnel shape (in preventing backflow of fuel gas into the fan). The SE HQ93 Stainless Steel Flask Funnel is an excellent example of such a shape being used as a safer air entrance for fan-induced burners.

Note: The moving fan blades you are concerned with here are impeller blades, which have become standard on axial computer fans; not the old-style flatter blade designs that are meant to push air forward; those increase the pressure of incoming air. Impeller blades lower the pressure of incoming air.

    Of course, this leaves us wondering how long a funnel is long enough. Only experience can answer that question, but I suggest a minimum length of one and a half times the diameter of the air opening. Furthermore, fan strength, constrictor shape (straight, convex, or concave) all come into play. Add to it how much curvature at what point in a funnel shape, and we are reduced to trial and error. Always remember that, if the burner you design starts backfiring into its fan, there is little work needed to change it to a naturally aspirated design. You don’t have to rebuild the whole burner.

[Mikey98118]

Vortex Burner fundamentals

 

(Advanced linear burners)

 

    Let’s start by clarifying just what is meant by the term “vortex burner.” Burners that swirl the flames they make are often touted as vortex burners. But causing a flame to swirl happens far too late in the air/fuel mixing process to provide much benefit; used this way, the description is mere hype.

 

    Vortex is a fluid dynamics term, describing a region where the flow of gas or liquid revolves around an axis line.  The vortices generated on the tailing edge of a plane’s wing just create drag. At the other extreme, a tornado’s funnel is powerful, but only destructive. The gentle current of a bathtub drain effectively employs vortex flow to good purpose, and so should your burner’s air entrance.

 

    For good combustion, it is necessary for incoming air to mix sufficiently with a burner’s fuel. A swirling motion provides the most mixing for the least drag on your burner’s gas/air mixture flow.  When incoming air passes through a constricting tubular shape (ex. pipe reducer or kitchen funnel), vortex movement is generated, becoming an excellent air/fuel mixing aid. Most successful burners, whether linear or not, create at least some vortex flow. My high-speed tube burners are an exception; they gain swirl from three (fore and aft beveled) rectangular side air entrances,. Nevertheless, if you place a pipe reducer between their air entrances, and a smaller diameter mixing tube, even their performance will be enhanced.

 

    If most successful burner designs create vortex flow, why bring it up? Because the people who designed those burners, only pictured them as swirling incoming air into a stream of fuel gas, and thought no further. “V” burners, both passive, and fan-induced, showed be deliberately designed to enhance vortex flow, and then to derive maximum benefit from it.   

 

    Any device that provides lateral air movement at a funnel opening, will increase vortex flow; this includes the opposed air openings on “T” plumbing fixtures, disc shaped choke plates near funnel entrances, or (my favorite) motionless blades in front of a funnel opening. If you strip the impeller blades from a cheap or worn-out axial computer fan, and mount them on a linear gas tube at a burner’s funnel opening, they will significantly increase vortex movement through the funnel, even though they are still, because they start lateral air movement (spin) at or even before the opening’s entrance, rather than within the funnel.

 

    Installing axial computer fans on linear burners will supercharge vortex flow, but this requires a trickier gas assembly, and an electrical power source. So, it is easier for novices to move from passive to powered “V” burners in stages.

 

    Some parts used for air openings on naturally aspirated burners also work well with a moving fan, while others do not. However, the limits on shape and sizes imposed for use with moving impeller blades, do not apply to motionless blades; these can be mounted on linear gas tubes (parallel to the burner’s axis) without struggle or worry.  

 

    Straight or curved wall pipe reducers, kitchen funnels, and other constricting tubular shapes provide convenient ready-made reasonably priced burner openings for incoming air to revolve its way through, and into the burner’s mixing tube; its ever-decreasing spiral path increases its rotational speed, along with its forward velocity (by about one-half of its rotational speed). Also, the faster the incoming air’s rotation the lower the pressure of the air flow through the mixing tube; this is all very good for mixing, but requires the mixing tube to be lengthened enough to stabilize the flame (because friction within the tube slows down the mixture’s swirl and forward velocity, before it exits).

 

    Or, internal vanes near the tube’s exit can be made to slow air spin, in order to keep the mixing tube’s length shorter. A larger diameter flame retention nozzle can act to break the flow’s exit speed sufficiently. Thus, you would need to exchange your smaller flame retention nozzle, used at lower gas pressures and fan speeds, for a larger one, when running a fan-induced burner full-out.

 

    The first thing to keep in mind about funnels and other constrictive shapes, is that the greater the ratio between the air opening’s diameter and the mixing tube’s internal diameter, the stronger the vortex.

 

    Secondly, the shorter the length of the funnel the greater the drop in air pressure it creates at the opening. This drop in the pressure of incoming air isn’t sufficient to create a problem in naturally aspirated burners, but when added to the low-pressure zone created with moving impeller blades, backflow can draw some fuel gas into the fan. Then, the fan’s electrical sparks will ignite the fuel/air mixture.

 

    So, a maximum 3:1 ratio between entrance diameter to the mixing tube’s internal diameter, becomes the first safety margin with fan-induced burners; another safety margin is provided with sufficient length in the funnel shape, or the addition of a short tube section between the funnel opening and the fan; this has the same effect as a longer funnel shape (in preventing backflow of fuel gas into the fan). The SE HQ93 Stainless Steel Flask Funnel is an excellent example of such a shape being used as a safer air entrance for fan-induced burners.

 

Note: The moving fan blades you are concerned with here are impeller blades, which have become standard on axial computer fans; not the old-style flatter blade designs that are meant to push air forward; those increase the pressure of incoming air. Impeller blades lower the pressure of incoming air.

 

    Of course, this leaves us wondering how long a funnel is long enough. Only experience can answer that question, but I suggest a minimum length of one and a half times the diameter of the air opening. Furthermore, fan strength, constrictor shape (straight, convex, or concave) all come into play. Add to it how much curvature at what point in a funnel shape, and we are reduced to trial and error. Always remember that, if the burner you design starts backfiring into its fan, there is little work needed to change it to a naturally aspirated design. You don’t have to rebuild the whole burner.

[elimsprint]

Where do you find .030" capillary tubing? I have been doing searches all morning and I can find no .030" SS capillary tubing (at any sort of reasonable price) in Canada and shipping from the USA is nutz ($12.50 order (10cm of tubing) $28 shipping) Any leads would be appreciated. I'm also searching and searching on here for plans for a good 1/4" burner and I can't find any. I'm using google and 1/4" propane burner, iforgeiron in my searches but I guess my searchfu is not working today.

[Mikey98118]

Every country has hypodermic needles. Look up a needle size chart online to find out what size needle while provide you with an approximately correct inside diameter (these very between one manufacturer and another, do to different thicknesses used to make the needle's wall). Choose a likely needle to trap a 9/16" long section within a MIG contact tip. Use #400 grit sandpaper to shorten it gradually, while checking the flame it makes in your burner. This tuning method works becuase of the very high amount of friction the fuel gas creates in very tiny tubes.

[elimsprint]

Hypodermic needles, why didn't I think of that????? Thank You!

[Frosty]

That's why we hang out here, we rely on somebody to point out the obvious to us and get to return the favor. It's the power of some 60,000 member blacksmith's cocktail party and the free exchange of information.

I live for those head slapping, "why didn't I think of that!" moments.

Frosty The Lucky.

[Mikey98118]

Burner sizes

The first thing you must decide about your burner is what size it’s going to be. Home-built burner sizes are given according to schedule #40 pipe sizes (or equivalent inside diameters in round tubing) used as the burner’s mixing tube, because these burners were built from pipe for many years (and many still are). So, it’s handy to know what actual inside diameters these nominal pipe sizes have, since it’s the inside diameter you’re trying to match in a gas orifice diameter size, and with whatever you use for an air opening.

    Actual pipe diameters are larger than nominal pipe sizes, both outside and inside. If you choose tubing instead, it will seldom be an exact match with pipe, so choose a little larger inside diameter, when possible, rather than a little smaller, for your burner’s mixing tube. Metric stainless-steel tube can be a handy alternative to fractional tube in the smaller sizes, and is more likely to match up well with most stainless-steel funnel shapes.

 

       Schedule #40 pipe dimensions:                    Nearest metric tube equivalents:

(A) 1/8” pipe is 0.405” O.D. x 0.270” I.D.      10mm (0.390”) O.D. x 8mm (0.312”) I.D.              

(B) 1/4” pipe is 0.540” O.D. x 0.364” I.D.      12mm (0.468”) O.D.  x 10mm (0.390”) I.D.

(C) 3/8” pipe is 0.675” O.D. x 0.493” I.D.       14mm (0.546”) O.D. x 12mm (0.468”) I.D.

(D) 1/2” pipe is 0.840” O.D. x 0.622” I.D.     18mm (0.702”) O.D. x 16mm (0.624”) I.D.

(E) 3/4” pipe is 1.050” O.D. x 0.824” I.D.      Use pipe nipples, couplers, & round tube.

(F) 1” pipe is 1.315” O.D. x 1.049” I.D.          Use pipe nipples, couplers, & round tube.

 

(1) A 1/8” burner’s nozzle size is 0.493” I.D; this is sufficient to heat 22 cubic inches.                       

(2) A 1/4” burner’s nozzle is 0.622” I.D.; this is sufficient to heat 44 cubic inches.                       

(3)  A 3/8” burner’s nozzle is 0.824” I.D.; this is sufficient to heat 88 cubic inches.                       

(4) A 1/2” burner’s nozzle is 1.049” I.D.; this is sufficient to heat 175 cubic inches.                           

(5) A 3/4” burner’s nozzle is 1.315” I.D.; this is sufficient to heat 350 cubic inches.                              

(6) A 1” burner’s nozzle is 1.61” I.D.; this is sufficient to heat 700 cubic inches.

Note: “Sufficient to heat” means that it can raise a properly built forge interior of those cubic inches to welding heat, or melt cast iron in an equal size casting furnace. Are these figures legitimate? In fact, they are under stated; not over reaching. What about the optional second (larger) flame retention nozzles on fan=induced burners? Whatever inside diameter is used with one of them, with the gas pressure turned up to match the fan running at full speed, can be considered as producing a flame equal to the nozzle size in a naturally aspirated burner.

    The number of cubic inches that can be brought to welding temperature in a properly built forge, or the number of cubic inches in a casting furnace that can be brought to iron casting temperatures (from a burner with a neutral flame), depends on the inside diameter of its flame retention nozzle; this is limited by the diameter of a burner’s mixing tube, in naturally aspirated burners.

[Mikey98118]

Of course these figures are for naturally aspirated burners. Burners with fan-induced air flow, to add to  the air induced from a gas jet can easily double these figures.

[Mikey98118]

Thoughts on manipulating flame shape

Because of my interest in silver brazing, and desire to find a way to braze weld "on the cheap," that is to say without need for an oxy-fuel torch, I pay especial attention to burner flame shapes, because, once you get beyond silver brazing, and into hard brazing (AKA spelter brazing, or braze welding), the flame is used to guide puddle formation, to create proper weld beads.

 

so, I just finished watching a burner build video, where my chuckles about  the builders lack of any idea what he was doing were strangled by the entirely unexpected result; a superb flame with superb control...duh...he joke's on me

A little background: The guy used pipe reducers of the same size at both ends of his mixing tube, which made his flame retention nozzle adequate, but his burner entrance way undersized. Then he made his own gas pipe by drilling out a bolt, pushing a MIG contact tip into it, and then sealing it in place with solder. A nut soldered to a fender washer became his variable choke. a 1/2" by 1/2" square bar was drilled and threaded on one end to make a mounting for his gas pipe, and it other end was welded onto one of the pipe reducers. I was prepared to see a sickly excuse for a flame as the outcome, but no--the flame was exceptional. How did he do dat, huh!?! Oh, yes the burner looked to be a 1/2" size--but the mixing tube looked to be two feet long.  The length allowed lots of time for the gas and air to mix thoroughly, and lots of length for friction within the mixing tube to complete eliminate any swirl in the mixture as it exited the flame retention nozzle; especially since the undersized air entrance didn't create much swirl in the first place.

All very well, but what's the point, since this would be pretty cumbersome as a torch? Internal fins can do the same trick with a much shorter mixing tube...

[Frosty]

I've had similar surprises and have related this one in the past. Nah, I just deleted that long ramble about a side arm build that came from a mistaken verbal description of the T burner in the early days.

Frosty The Lucky.

[Mikey98118]

Larry Zoeller's modified side arm burners are worthwhile, the the original mistaken design is best deleted.

[Frosty]

Ah, Robert's burner worked well enough, he didn't coin, "Side arm" and I don't believe I've seen anything of his or him in decades. He was looking for a burner he didn't have to bring a generator to use. 

Larry's improvements made a good quality effective burner whatever you put it in. 

I only brought it up because your experience with a oh so wrong burner working really well, reminded me of one of mine. I only used "side arm" to describe it because almost everybody knows what one looks like and illustrated my memories nicely. 

Heck, this pattern plumbing fitting built jet ejector has been in use for probably as long as you could buy plumbing fittings. But as vacuum pumps, a Squid friend of mine used to have to put one together from large diameter plumbing to vacuum the bilges dry on Navy ships when they needed to work in them. They powered them with steam and built them from ship's stores because the parts were pretty universal on all ships. 

It was funny, he kept telling I'd built it wrong, it'd never work. Then I lit my forge and viola. 

The memory sticks clearly because I've experienced it from both sides. Good memories.

Frosty The Lucky.

[Mikey98118]

Even with a good working burner, Larry kept on looking to improve it, and came up with an even better working burner, from easier to find parts (if I remember correctly he calls that one a "Z" burner); he also started using/selling Plistex years before anyone else. That fella's got a sharp eye.

I met Larry at the 2004 ABANA show in Kentucky; he was very outgoing then, and full of enthusiasm. We emailed back and forth afterward, until something heavy happened in his life; I don't know what, but he became almost none existent. It was a lot lime Ron Reil, except that Ron's troubles were known, and Larry kept mum about his. Of course, I wish they would both come back to us.This whole "ships in the night thing" is such a downer.

[Mikey98118]

On 11/7/2022 at 2:17 PM, Frosty said:

I've experienced it from both sides. Good memories.

Yes; good memories from both sides. Personally, I don't care if somone crosses the finish line dancing or gasping, so long as their burner's flame makes the grade

[Frosty]

I'd heard Larry had some hard times but not what. Great guy I miss him. 

When I got over thinking it was some kind of contest I've been a happier guy.  It was hard not to be competitive about burners but it's a good flame that matters.

Frosty The Lucky.

[Mikey98118]

Contests are alright, so long as we laugh at ourselves and don't take them seriously. "Ah, there's the rub."

[Frosty]

 Agreed.

The local, "Palmer Curling" club started playing again after Covid hamstrung everything and I made my first bonspiel last Sunday. Cast a few stones after they were finished playing and Dang beginner's luck, made 3 for 3 inside the 8' ring, even made them curl. Everybody putting things away stopped and cheered.

It was so curling. Competitions are fierce but everybody cheers a good shot or take out, even if their stone was taken out or points were stolen.  I may have to register and play next time they have the ice. 

It reminded me of playing games evenings at home. We always played for blood but cheered good plays win or lose it was for fun. 

Frosty The Lucky.

[Mikey98118]

Funnels that are easily attached to mixing tubes: SSTs (sausage stuffing tubes) are your easiest construction choice, if you can find them in the size you need, at the time you need, and a price you like; due to vagaries of the marketplace, that can be a hit-or- miss proposition. So, here are some alternate choices, starting with some icing tips.

    Cake decorating tips have long stainless-steel cones: Cake decorating tips are the best general source for long funnel shapes on very small burners (all burner sizes up to 3/8”); most of them require silver brazing to mixing tubes, but are a superior shape to almost any other funnel source in these sizes, with the possible exception of the long cone side of Japanese style double jiggers, which only come in sizes fit for use on 3/8”, and 1/2” burners.

    Icing tips with their own tube already attached are far cheaper to use than small SSTs, but don’t have inbuilt flanges; these can be made by drilling holes in sheet metal, which are a little smaller diameter than the icing tip’s funnel opening, and then beveling the hole edge to match the funnel’s taper. Input “cream filling icing nozzles” in your word search, and this kind of nozzle will come up right away. Otherwise, you will have to search through pages of regular icing nozzles to run across the occasional ad for this type.

    Because some tips are too short, they will need to have stainless-steel tubing slid over the tip’s existing tube. You may end up with a perfect sliding fit, or you may need to shorten the existing tube, and power sand or grind the end of the tube being slid over it, to create an interference fit; in this case, look to see how deeply your chainsaw grinding stone, etc. will reach into the tube, and cut the icing tip’s tube a little shorter than that.

    Keep checking the enlarging opening in the new mixing tube’s end, so as to stop enlarging it, when the tips shortened section of tubing will slip into it about 1/2” deep. Because tubing can be slightly out of round, twist the tip’s tube within the mixing tube, to establish where they fit together best; this will help establish the best interference fit. Finish pushing the tubes together by lightly tapping them. It is a good idea not to cut the mixing tube to length, until after it is tapped into place; this keeps the tube’s cut end from being deformed by gentle hammering on it.

    If you over enlarge the mixing tube’s end, you can still silver braze, silver solder, or glue the parts together.

Onwon 2 pcs. Cream Icing Piping Nozzle Tips ($7.98).

BLLNDX 3 pcs. Cream Icing Piping Nozzle Tips ($8).

Dxhycc 8Pcs icing tip set; stainless-steel, for $10 through Amazon.com; the funnel opening diameter on the two largest tips is 0.893”. The inside diameter of these two tips is 0.357” I.D.; they will have 3-1/2” of useable length after cutting off their slanted ends; this is just fine for using the existing tube as your burner’s mixing tube for naturally aspirated mode, or 5” length of 12x10mm stainless-steel tubing can be slid over it for use as a mixing tube, if they are to be fan powered. Such a burner will have a 2.5:1 opening to mixing tube ratio, which is sufficient for naturally aspirated 1/4” burners, and invites use with a 25mm computer fan, which fits perfectly on it; also good for naturally aspirated.

    There are also two tips with funnel opening diameters of 0.935”; the inside diameter of their tubes are: 0.291”, which is excellent for 1/8” burners; this calls for a minimum mixing tube length of 2-3/4” for naturally aspirated mode, or 4” long if they’re fan powered. You will need to slide a 10x8mm stainless-steel tube over their existing 8mm O.D. tubes to make 1/8” burners from them.  Such a burner will have a 3.2:1 opening to mixing tube ratio, which is excellent for a naturally aspirated burner, and okay for use with a 25mm computer fan. All the remaining icing tips are useless for turning into burners, but useful for silver brazing practice.

SUODAO 4Pcs icing tip set; 5mm, 6mm, 8mm, and 10mm diameter stainless-steel tubes, for $8.49 through Amazon.com. You have tips to build 1/8” and 1/4” burners among them; good for naturally aspirated or fan powered.

    The 10mm tip has a long cone, with an 0.897” opening (moumt 25mm fan+), on a 10mm tube, that will end up 3.24” long after the end is cut square; just long enough to serve as the mixing tube for a ¼” naturally aspirated burner. It is easy to add a 12mm x 10mm x 1” long S.S. spacer ring. Then push a 14mmx12mm x 1-9/16” flame retention nozzle over the spacer ring. Stainless-steel metric tubing is easily ordered through Amazon.com.

    The 8mm tip has a short tube, which will require an outer tube slipped over it to create an oversize 1/8” burner. And the two smallest tips aren’t worth repurposing into burners, but can be used to perfect your silver brazing technique, before working on the larger tips.

HULISEN 4Pcs icing tip set; these stainless-steel cake decorating tips cost $10 through Amazon.com; they come with a tube firmly attached, apparently by swaging; they have a 1” diameter opening on a long cone; the tube’s outside diameter is 0.314” (8mm)  x 0.285” inside diameter; this provides a sliding fit inside a 10 x 8 millimeter stainless-steel spacer tube, which fits inside a 12x 10 millimeter flame retention tube, with minor   grinding with a rotary stone for chainsaws run in a rotary tool; this can be used to make  1/8” burners; good for naturally aspirated or fan powered.

Concentric thin wall (schedule #10) stainless steel butt-weld pipe reducers make moderately priced mechanically attached burner funnels; they can be mounted to mixing tubes with set screws, and are quite strong. You can attach the gas mounting plate in place by silver brazing, soldering it in place—after adjusting the distance from gas orifice to mixing tube. Some of the reducers can be improved with some internal smoothing from a sanding disk in a rotary tool; others come smooth enough. Several sources are listed below, because available sizes and pricing fluctuate. All of these reducers are good for naturally aspirated or fan powered.

Empty Co2 cartridges. 

[Mikey98118]

So, both the Onwon, and BLLNDX icing tips cane today; all of their tubes are too small to use for burners.

 

[Mikey98118]

Linear versus tube burners: basic facts

A better title might be linear versus jet-ejector burners. However, what I am expert in is only my own burner designs, so such a generality isn't likely to be accurate; not from me, anyway. So, "tube burners" will have to do.

Let's start with a confession: Before I ever designed my first jet-ejector style burner, I had already perfected Linear burners PAST the performance of my best tube burners. No; they weren't hotter than a Mikey burner, or a Hybrid burner. But, like speed isn't everything in a jet fighter, heat isn't everything in a burner. Tuning variations in a burner is the equivalent of maneuverability in the fighter.

Getting straight to the point, a first-class tube burner will be no hotter than a first-class linear burner. But the linear burner can be tuned far more precisely than the tube burner. Normally, the difference is unimportant. Who wants to do tricks with their burner's flame? However, one of the "tricks" that a linear burner does well, because it is more variable, is to maintain a good turn-down range in miniature burners; the other side of that coin is that a perfect flame can be maintained when a miniature burner is turned way UP.

Than, why design tube burners? Nearly all linear burners depend on a funnel shaped air entrance; its opening must be at least 2.5 times the inside diameter of the burner's mixing tube; 3 times its diameter is much better. In the larger burner sizes those funnels start getting awkward.

But, ever hotter burners allow ever smaller sizes to do the same jobs. Funnels in miniature burners aren't awdward at all.

[Jimw3326]

So, Mikey98118 what is the optimal position of the orifice relative to the inlet?

My results may be different after I rebuild the burner but as the pic shows it is above the edge wide open. To get it to run the choke was about 1/2-3/4" above the orifice.

Edited December 11, 2022 by Mod30
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[Mikey98118]

36 minutes ago, Jimw3326 said:

what is the optimal position of the orifice relative to the inlet?

I am assuming that you are actually referring to what we call the sweet spot." There are bound to be differences in terms. The sweet spot is what we call the optimal distance between the MIG tip's forward end, and the air openings forward ends, or in other words the point where the area of the burner's air openings stop, and the area of the burner we call its mixing tube begins. On a 3/4" size burner that will be somewhere between 3/8" and 1/4."

First, you want to finish squaring the forward ends of your air openings.

Next, you want to grind a sixty degree internal bevel on all those squared ends.

Third, you want to set the end of the MIG tip 3/8" away from the outside edge of the air opening ends.

Fourth, tune your burner to the best flame you can by varying the length of the flame retention nozzle's overhang past the end of the mixing tube; that will start at a distance equal to its inside diameter, plus 1/8" (on a properly built slide-over step nozzle). You will find the flame varies  between slightly reducing at that distance, and oxidizing as you move closer by subtracting the whole 1/8".

You make a proper slide-over step nozzle by cutting a tube or pipe the next size larger than your burner's tube body, and 1" long; we call this a centering ring. Then, you cut an outer tube or pipe the next size up from that to form the flame retention nozzle; its length is to match its inside diameter, plus 1-1/8". You will find this nozzle will produce a much hotter flame than the ones you have now.

You can use mild steel tube or pipe for the centering ring, BUT you need to use stainless steel socket set screws on you flame retention nozzle. You also want to use stainless steel for the outer tube; #316 is best, but #304 will serve.

Usually, I need to due some minor power sanding on the outside of the centering ring to get to push into the outer tube, and some minor power sanding on its inside to get a good sliding fit between it and the mixing tube, but I have been know to slit the centering to make less than optimal part sizes serve. Also, you must remember that pipe, and to a lessor extent, tubing isn't round, so you need to check the ring and outer tube to see where they mate best; this reduces your work and improves the finish product.

If all goes well, a single screw will do the trick; otherwise, you will at least need three equally spaced screws in a line 1/4" away from the nozzle's rear edge. Why there? Because that leave  an area 3/4" away from the edge available for a second line of screws, if needed. Do I think you'll need to go that far? Heck no; but other are reading these instructions too

 

You are now finally ready to move your MIG tip back and forth between the 3/8" and 1/4" distances, to fine tune your burner's flame.

Also, get rid of that short MIG tip; replace it with an 0.025" tip that is 1-1/2" long.