Burners 101

[Frosty]

Probably trace elements in the iron. Everything is changing from analysis specification to performance specs so as long as it's strong enough what's in it doesn't matter.

Frosty The Lucky.

[Mikey98118]

That's true for most readers. But, I try to be completely accurate with my so called "facts." For a long time I assumed it was chromium ions causing those red streaks, and might have said so. Therefore...

[Frosty]

The ONLY way to be accurate about something you can't know is to say so. I understand, I like to be accurate and it's tough not to be able to give definitive answers, especially in a thread as good as this one. Unfortunately there's just no knowing what's in steel these days, especially non structural steel. The manufacturers don't care so the steel suppliers don't. My only concern is dangerous impurities like cadmium or lead, they burn off easily and cad especially is high end toxic.

I don't have a good solution, I wish I did.

Frosty The Lucky.

[Mikey98118]

I relaxed quite a bit once I realized that things seldom get worse, and seldom get better; they just change constantly. Don't try to fight the flow. A good back stroke will keep your head above water. Besides...the falls are miles downstream

[Mikey98118]

Propane orifice connectors are used on various camping stove and turkey friers, to connect copper tubing to burner entrances, and also to act as gas orifices in their burners. What is interesting about them is their small gas holes, which can be drilled and tapped for 3D printer nozzles; thus, allowing easy access to small gas orifices in ever smaller “T” burners.   

 

 GasOne Propane Orifice Connector Brass Tube Fitting 3/8" Flare x 1/8" Mnpt or Male Pipe by Gas One. Available for $4.23 through Amazon.com.

1/8" MNPT Propane Nozzle for Freestanding Casting Cooking Stove Grill, Turkey Pot Cooker Set of 2 for $8.99 through Amazon.com.

[Mikey98118]

Gas Orifices

The gas orifice on a burner must closely match its diameter in relation with the inside diameter of the 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 with capillary tube trapped in them as 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 have 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) comes to 0.0117” diameter; a good gas orifice size on a 1/8” burner.

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

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

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

0.7 (millimeter) comes to 0.0273” diameter; a possible gas orifice size on a 1/2” burner.

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. Simply employ tape to keep the fender washer in place over the large opening during testing; permanently mount the washer and gas assembly in place afterward. Start with the end of the gas orifice at 3/8” short of the opening; its sweet spot will end up somewhere between 3/8” and 1/4” away from the opening.

[Hefty]

Mikey,

I've been looking at using 3d printer nozzles for my burners as they are more readily available to me so the above info is great, thank you. Do you know if there are any issues caused in terms of jet stream, turbulence, etc by their very short section of final diameter, compared to the 1/2" long "through hole" in the mig tips?

If I have to include putting a capillary tube in the 3d printer nozzle, then I'm back to mig tips being the most readily available "off the shelf" option so any clarification would be great.

EDIT: nevermind, I just re-read the start of your post and it answered my question!

Edited September 8, 2022 by Hefty
me stoopid readin

[Mikey98118]

1 hour ago, Hefty said:

Do you know if there are any issues caused in terms of jet stream, turbulence, etc by their very short section of final diameter, compared to the 1/2" long "through hole" in the mig tips?

In the first place, thank you for posting that sketch

The through holes in the MIG tips that I have always recommended are 1" long; the tips themselves are 1-1/2" and 1-3/4" long, depending on brand. The tips you are describing must be the newer short variety (came along in the sixties). No matter either way, for I stated that printer nozzles were just as good (for creating a useful jet stream) in 3/8" and smaller burners, and about equal to MIG tips in 1/2" burners, becuase smaller orifice diameters create so much friction that printer nozzle's approximately 1/2" long orifice tunnels (through-holes) are sufficient. On 3/4" and larger burners they are not sufficiently long, but then those larger burners are already well served with MIG tips.

[Frosty]

Not to intrude on a thread that's being so well served by Mike but the length to diameter of jets is a function of the ratio not the specific dimension. That means when you're talking about that small a diameter orifice a much shorter length makes a laminar flow in the propane stream. 

It's the length to diameter ratio that smooths the gas flow. Heck it might even be the same ratio as the mixing tube dia. to length ratio but that's deeper into the math than I play.

Frosty The Lucky.

[Mikey98118]

Deeper than I play too, but the thought has come up. I try to keep things so simple that they should be obvious. Obviously, the friction from a very small diameter gas orifice can be offset by raising gas pressure. What isn't at all apparent is that the gas molecules that are blasted out of the orifice, then have too much speed, so that many of them outrun the oxygen molecules, which that gas stream is inducing into the burner; this results in a fuel rich flame, which cannot be corrected, because the problem has been built into the burner design 

Don't ya just hate when we trip ourselves up?!? How many times I can remember sprawling on the ground (usually in front of a crowd), hating those traitorous feet; its all their fault. They did it

[Frosty]

Doesn't that mean you're using too small a jet? What you describe above is the problem wit using too small a jet for the burner isn't it? Fluid delivery through an opening is a function of orifice area x psi, no? The greater the volume through an orifice the greater the velocity. Right?

The issue you describe with the gas jet out running the mix in the tube is why I try to run as large an orifice as reasonably possible in a burner. I however see the opposite effect of your description. I see small high velocity jets that out run the flow producing lower pressure and inducing too much air. Hence the necessity for chokes. 

Did you know you can replace the jet in your type 5(?) burner with a 0.035 mig tip, remove the choke sleeve all together, trim the jet back a little for a slower neutral flame? 

Frosty The Lucky.

[Mikey98118]

3 hours ago, Frosty said:

Doesn't that mean you're using too small a jet? What you describe above is the problem wit using too small a jet for the burner isn't it? Fluid delivery through an opening is a function of orifice area x psi, no? The greater the volume through an orifice the greater the velocity. Right?

Yes, that is exactly what it would mean. Using too small a jet leads to similar problems as using too large a jet; the mechanism is different, but the result is similar; not the same, but also far from satisfactory.

As to velocity; the greater the gas pressure the greater the velocity. Isn't that what you meant to say? If so, than yes to that too. And too high a gas velocity was the first unanticipated problem I stumbled over with my earliest burners; its the old more is better stumbling block yhat our generation was encouraged in

[Another FrankenBurner]

My experience with too small an orifice is a lean mix.  Sometimes lean enough to not be in the flammable range.  Even when it is in the flammable oxidizing range, an overly aggressive nozzle may be needed to slow down the high velocity fuel/air stream.  

The BTU energy available in propane is based its volume (and proper air ratio with good mixing).  If you decrease the size of the orifice, then you need to increase the pressure to maintain the same fuel volume.  This means an increase in fuel stream velocity which means a lower pressure in the throat of the burner which means more air entrainment.  More air for the same fuel volume.  Leaner. 

It is a balance thing, nothing more.  The scales can be tipped based on specific user desires (lowest fuel pressure, maximum energy output, etc.).  My Goldilocks orifice induces the proper ish air at the widest happy fuel pressure range. 

[Mikey98118]

2 hours ago, Another FrankenBurner said:

My experience with too small an orifice is a lean mix.  Sometimes lean enough to not be in the flammable range.  Even when it is in the flammable oxidizing range, an overly aggressive nozzle may be needed to slow down the high velocity fuel/air stream. 

That is my experience too--generally. What I am describing is do to too much friction in a gas orifice. The starting point of this discussion was why I find  the very short orifices on printer nozzles to be appropriate on 3/8" and smaller burner sizes, although they are not appropriate on 3/4" and larger burner sizes. It all comes down to friction. The smaller the gas orifice diameter through a tubular opening the shorter that opening needs to be.

[Another FrankenBurner]

I played with orifice channel length a bit but not enough.

At one point I was over drilling 3D printer nozzles to match long tapered mig tip orifice diameters. I built a manifold to connect them both to a water supply to compare the streams.  The 3D printer nozzle steam always went straight line considerably further.  Less friction, higher volume, higher velocity.

I imagine water and propane play a bit differently but it was mostly a food for thought experiment.

In burners, I saw increased output at a given pressure.  Higher fuel delivery inducing more air.  Or lowering the fuel pressure to output the same.

I suspect the fuel velocity/volume ratio increases.  Higher fuel velocity at a given delivery volume.  I am able to run the 3D printer nozzle burners to lower output levels before air induction drops off.

In the commercial hvac/cooking appliance world, I have not seen any orifice length over 1/16th inch long. They are running quite low pressures so the orifice diameters are very large by comparison.  On higher output burners, the diameter is sometimes larger than the channel length.  These burners have much different purposes/requirements so it’s probably an apples oranges kind of thing but it’s interesting. 

[Frosty]

11 hours ago, Another FrankenBurner said:

It is a balance thing, nothing more.

Just so. This little bit of discussion is very similar to one we had a couple years ago maybe. Someone had access to precision small Dia. tubing as drops where he worked and asked if using long lengths wouldn't result in a more laminar flow, be better. 

In that case friction in the long tube required higher psi to deliver sufficient propane and resulted in a screaming fast jet. 

I believe this current bit of discussion is a rehash, as much for new members as for experienced burner folk. 

For myself I've found working with ratios rather than calculating dimensions made finding the fuel air balance easier. I discovered that because I wanted to put as much fuel/air in the forge per second as possible. Turned out the goldilocks ratios resulted in low flame velocities too. 

Frosty The Lucky.

[Another FrankenBurner]

Flame velocity… that topic makes my head hurt. 

[Frosty]

Heh, heh, heh, 

We were typing at the same time there so my post was kind of dated but what the hey. 

You make a terrific induction device so come closer to a commercial burner. Multi port burners like stove burners operate at really low jet velocities and still induce decent fuel air ratio flames. I realized a long time ago that if I wanted to produce burners that effective I needed to either buy a stamping press and machine the dies to make the proper shape burner bodies. They need to have the right shape and size intake body and more importantly the proper aerodynamic constriction (throat) followed by a long tapered mixing tube with a MAX, expanding taper of 1:12. 

1:12 is NOT the best ratio it is the MAXIMUM taper that will not cause induction killing turbulence. 

If I wanted to set up a metal spinning lathe and machine split tooling I MIGHT be able to produce commercial level effective burners. However my goal was to produce a reasonably effective burner that required the bare minimum shop equipment and skills so almost anybody could build an effective propane forge. And me being me I developed for the most fuel/air per second I could jam into a furnace volume. Hence the T burner.

A low velocity flame was serendipitous, not part of the design plan. It was an unintended consequence purely because I didn't think that far. I look back and it's pretty obvious had I thought about it. Hmmm? 

You on the other had have put an enormous amount of thought, and development into a burner that is far more sophisticated and effective than a T burner. It's one downside almost makes it a deal killer at current tech level, it REQUIRES sophisticated tech to build. Give it a couple years, 3D printers are becoming affordable to more people and soon will probably approach Cellphone levels of common tech and I'll have vortex burners on my forges. 

Then again, guys who are at a drill press, tap and die skill / tech level, will have T and Side arm burners on their forges. 

BUT everybody who wants a forge enough to get off their butts and build one will have an effective gas forge. With an effective gas forge and a little gumption they can shoe string themselves into whatever level they can seize for themselves. If they develop something different that does the job, effective or not, so long as it does the job all the better. It makes me giddy. I ENTHUSIASTICALLY encourage anybody to look into and develop new ideas for burners, forges and heck every darned thing! The more development there is in the world the richer we all are. PFT to the doom criers! Check this guy out. https://www.bitchute.com/video/6iC_hY4qhyk/

I'm watching for an affordable effective induction forge. The sadly passed to young, Grant Sarver was barreling ahead on that great guns, he was turning out more effective and less expensive induction forges a couple three times a year. 

I can't tell you how much I miss Grant. <sigh>

Frosty The Lucky.

 

[Mikey98118]

6 hours ago, Another FrankenBurner said:

I imagine water and propane play a bit differently but it was mostly a food for thought experiment.

I find them to act quite similar, for short distances, which are all that matter in burner systems.

[Mikey98118]

As to what Frosty has to say: me too!

[Hefty]

On 9/9/2022 at 11:52 AM, Mikey98118 said:

smaller orifice diameters create so much friction that printer nozzle's approximately 1/2" long orifice tunnels (through-holes) are sufficient.

When you say through-hole or orifice tunnel, does that mean the length of the section that is at final orifice diameter? That was what prompted my first post. Then I thought I had it, now I'm confused again 

The tunnel diameter for most of the inside of the printer nozzle is 2mm diameter and only the tip (I'd estimate less than 1mm) is at the true orifice diameter. If I understand your description of the mig tips, the final section/through-hole is all at the final diameter. 

I get what you're saying for smaller burners: at very small orifice diameters, it doesn't matter that only a tiny section at the end of the jet is at final diameter. But I wanted to clarify because above you suggest the printer nozzle has a 1/2" long orifice tunnel, but if we are talking final orifice diameter then that orifice tunnel is less than 1mm (.040")long.

Sorry, I'm not meaning to be a pedant, I'm just trying to clarify my understanding because if I am understanding you correctly, this will greatly increase my ease of burner construction.

Cheers,

Jono.

[Frosty]

Don't worry Jono, YOU aren't the pedant, at present Mike and I are displaying the trait. You're just asking for clarification while Mike and I are rambling on about minutia largely differing on opinion, rather than right vs wrong. You have every right to  be confused. 

Yes, I believe by "through hole" Mike is referring to the hole through the printer nozzle. We were talking about a small diameter jet diameter requiring less length to shape the flow. 

Mig contact tips are the same diameter full length so they're sure to make electrical contact with the wire over a long enough distance to minimize resistance. 

If  Mike says something different go with what he says.

Frosty The Lucky.

 

[Mikey98118]

32 minutes ago, Hefty said:

When you say through-hole or orifice tunnel, does that mean the length of the section that is at final orifice diameter? That was what prompted my first post. Then I thought I had it, now I'm confused again

Well, you did have it. You thought right. For instance, the Tweco style MIG contact tips that I use and recommend are 1-1/2" in total length; but, for the majority of that length its inner passage is narrowing, and only the final third (1/2") of that passage is parallel; this is called its "through hole." Now, don't jump to the assumption that only that last 1/2" is doing any good for flow, because the hole length of the tip is. In fact, I first started experimenting with MIG tips as gas orifices, because the Tweco tips were very similar inside, to torch tips...but a whole lot cheaper, and with convenient threads.

So, were does this term "through hole" come from. Believe it or not it is a technical term used by MIG tip manufacturers to describe that section of their products. I am going a little further, in applying it to the corresponding section of printer nozzles, but I think that it is warranted, yes?

[Hefty]

So, even though it is only very very short, the last little bit of a printer nozzle is the "through hole" and is still suitable for smaller scale burners. And the larger diameter before the end is still of some use for promoting good flow, similar to what you are saying about mig tips?

[Mikey98118]

1 hour ago, Hefty said:

The tunnel diameter for most of the inside of the printer nozzle is 2mm diameter and only the tip (I'd estimate less than 1mm) is at the true orifice diameter. If I understand your description of the mig tips, the final section/through-hole is all at the final diameter. 

That isn't a problem. As orifice diameters grow smaller, friction in a "through hole," piece of capillary tubing, or drilled hole in a brass part needs to shorten. The hew thousandths of an inch of a thickness in thin sheet metal served for years as gas orifices in many commercial burners. In fact they are used quite effectively in propane torch-heads to this day. Why? Because those torches run directly off of of propane cylinders, with nothing but a needle valve to modify pressure with, they are going to be running on the high side, which means very small holes are needed to keep the cylinder from being exhausted way to fast; so those tiny orifices need to be short to prevent friction through them from becoming a problem; its all a balancing act.

21 minutes ago, Hefty said:

So, even though it is only very very short, the last little bit of a printer nozzle is the "through hole" and is still suitable for smaller scale burners. And the larger diameter before the end is still of some use for promoting good flow, similar to what you are saying about mig tips?

Exactly so, my friend