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Whats the difference between nozzles? (various gasses)


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I searched around the net, searched for drawings and section of nozzles, even taken apart a couple nozzles, but gathered little...

Anybody knows what is the difference in working, design and components between butane, propane and MAPP torches? (the burner assembly)

Looking at the nozzles themselves I see different orifices, reading on the subject I found that in part those have the job of mixing the fuel with the hair but the big part of the design is to shape the flame in a certain way (like a mantle of slower moving gasses around a column of faster moving gasses to obtain a pencil flame of a definite shape etc)...
Googling the question I only found a couple threads in forums discussing it and no definive answer (someone mentioned nozzle orifices design, and others told him he was mistaking that for whats needed with acetylene...).
What I know is:
- burners I find in stores mention if they are for propane or MAPP, the butane ones sometimes look different (but only sometimes)
- Some people used propane burners with MAPP and complained that the burner just stopped working (no more gas coming out the torch... some people said they used old torches with both without any issue though)
- MAPP burners all work with both MAPP and propane without issue.
- Noone mentions using butane nozzles with propane.
- In some cases material used is brass with all of them (not sure about the valve itself)
- Some use the swirl idea some dont but its not strictly related to the kind of gas they use

From some more reading I see that the flame speed of the 3 is very similar and that butane wants a bit more air than propane for a good burn, but im not sure if that means that the only difference lays in a different size jet orifice or just that the way the venturi is sized, to have the right mix (noone of the nozzles I have seen use a choke... but nozzles shouldnt be difficult to modify adding a simple choke or switching the jet if the mix ratio is the whole point of the question). The other thing I was thinking is that maybe the whole difference is in the valve and its parts, like the way they handle the pressure or possibility that some materials in it is degraded by one gas and not another.

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Good Morning,

Welcome to this forum. There are a few members who play with what you are asking about. I'm sure they will chime in with details. I have found that you will be playing with different orifice sizes, to get your differences. I think that you are worrying about too much detail. I would suggest that you start playing with a Forge Burner and try to learn from it. Keep a written record, you can always go back to it. Some members try to run their Forges without any ends on their Forge and then can't figure out how to get it hotter. Pay Attention and Learn.

You are in Ontario Artist Blacksmith Association territory. They have a lot of VERY KNOWLEDGEABLE people. Don't be shy about going to some of their functions, check out their web-site for information. You will learn more by doing, than by talking with the keyboard!!

Enjoy the Journey,


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Hi Neil, being an ex modelmaker (jewellery industry models and props, there was a lot of work for people like me in the part of Italy where I come from, not so much where Im now) I did stick with jewellery and props people, even glassworkers (glassworkers have very nice stuff). Nice guys but when you talk about tinkering with torches they tend to avoid the subject. Blacksmiths seem more willing to discuss...
What you mean with "try to run their Forges without any ends"?

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When it comes to Propane, butane, Ametalyne and MAPP, they are all so similar that they interchange.  MAPP is just propane that has some additives to get a few more btu's.  Gasses like propylene and acetylene however are different and may require different orifices/pressures to get a proper air/fuel ratio.  Butane has a higher boiling point than propane so it's more prone to pressure drop if it's drawn too fast.

It's always wise to stay within the manufactures guidelines until you have sufficient knowledge as to not hurt yourself.

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There is no such thing as MAPP gas; there hasn't been since 2008, when the only MAPP refinery switched over to making propylene gas full time. 

There are quite a bit of differences between butane an all other fuel gases; this is because of its very low vapor pressure. Butane is only used for pocket lighters and blue flame jewelry torches; forget all about it for anything else.

This reduces your practical fuel choices to propane and propylene. When bought in refillable cylinders from a weld supply store, propylene costs about one-third more than propane. I estimate that what you'll get in return is between 600 and 1000 degree higher flame temperatures coming out of your burner, depending on how efficient its design is in the first place.

So, why would people spend about three times the amount for so called "MAPP" gas, rather than propane in canisters (non-refillable cylinders) down at their local hardware store? Because up to 1000 degrees higher flame temperature is a real big deal  when your flame is coming out of an air-fuel hand torch, and burning in the open air!

But, burned inside the average forge, it will destroy its structure, and melt the burner's flame nozzle...

There are hose parts called "Y fittings," and some of them have built in needle valves; one of the interesting tricks that can be done with them is to introduce two different gases, in varying proportions, into a burner; thus raising temperatures over what could be gained otherwise, without ending up with way more temperature than the equipment can handle.

You will not find any answers by tearing apart nozzles on propane and butane hand torches; everyone of them is built to deliver a delicate balance of mixture flow and flame characteristics that won't work for what you are probably trying to do (best on your research).

To make a wild guess, you're trying to get a propane or butane hand torch switched over to work well in a miniature forge; yes? It just so happens that I am walking down the same path. Look under the micro burner thread.

But, if it is that you are just trying to make a fierce flame come out of an inexpensive propane torch; you can buy one for $22; its already been invented, and can even handle propylene.


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I keep saying MAPP even for the MAP/PRO when in reality they are just different things. About the jets, what I've been told is that MAPP burners can be used with MAP/PRO, so as far as the burner parts go...

jmccustomknives, yes gathering knowledge about these things is what im trying to do, for sure I dont want (or can afford) getting hurt... The experience of others has a very high value.

Mikey98118, yes what I was wondering about is the possibility of turning commercial nozzles from other gasses (butane mostly) to propane... I dont intend to use other gasses in the forge.
Thanks for the torch model, although here in Canada costs more than double that...

I know people might think "just build one from a plan and call it the day"... But behind my questions is not only the need to build the forge and that I havent found a plan that is perfect for my needs, its also personal curiosity...

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With air, MAPP, propane, CNG will all burn within @ 100 degrees of each other. For nozzle design you might take a look at model rocketry. If you want to pursue a degree in engineering this would be a place to start as, if I understand what you are looking to do, you will need more than a rudimentary understanding of; chemistry, mathematics and physics to accomplish your goal. MAPP has a definite advantage over propane when mixed with pure oxygen.

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I am in the midst of putting together such a burner; it involves switching over a standard canister mount propane torch, by switching out its gas jet and head (AKA tip). The head is the part that holds the mixing area and flame nozzle; it threads off of the goose neck (the bent part of the gas tube that is threaded into the torch's  valve body). The goose neck also contain the gas jet; usually threaded into it, but occasionally only setting in position; trapped in place by the head. Once the gas jet is reconfigured, and the head is changed out for a stainless steel mixing tube and flame nozzle, a  very powerful miniature burner results.

A burner which can be hooked up to its own fuel hose and still run from canisters. or from any refillable propane or propylene cylinder, without need of a regulator (as I recommend for every other burner I build).

If you already have a regulator,  and if you only want a burner for a miniature forge, then you might consider simply building a 1/2" "T" burner. But, if you also want to use your burner as a powerful air/fuel hand torch, and want to even burn propylene fuel in it at times, than this is the burner you want to build.

As to the forge to put it, I would recommend in order of cool:

(A) A miniature oval shaped forge, built from a car muffler.

(B) A one or two burner arrangement. in a two gallon non-refillable refrigerant  or helium tank.

(C) A forge built from a three pound coffee can.

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Mikey, I see, im keeping an eye on the micro burner thread also.
How small you think the rebuilt nozzle could go? I was looking for something less than 1/2". I saw there is a thread already on how small you can go but didnt give much examples.

At this point im starting to connect the dots on a few things. What I cant find yet is how to size the orifice in respect to the mixingtube/nozzle.

The fine mesh in the nozzle stops a burn-back right?

Is it possible to build the mixing tube+nozzle directly casting them in refractory and make only the venturi in metal?

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Another formula 1 burner guy! Cool, do you have a name or web handle we can use? Calling you vanDoren is a little awkward. I'm kind of talkative and bounce back and forth with who I'm referring to or addressing.

Forget perfection, it doesn't exist on a commercial level or there wouldn't be new "Better" torches coming out all the time and especially on a home build level.

I use Mig contact tips for the jet in burners I build and trim the length to adjust air intake (vacuum induction) and fuel air ratio. It's not possible to make a T burner perfect or I could run some numbers and tell folk exactly how to build one for their location and conditions. Maybe somebody can, I can't I don't even try.

I operate with rules of thumb and build devices that can be adjusted to within acceptable operating range. A rule of life I operate by is: "It's better to be approximately correct then exactly wrong."

Ah, enough chatter, that's enough handle on how I do some things. Jet size is your question. Use the same ratio as you do with the burner tube. Increase the tube dia. + 25% = x2 the output. Reduce the burner dia. -33% = 0.5  the output. I haven't actually run my calculator across the apparent ratio but it appears to be the same.  increase the burner tube dia. 25% increase the jet dia 25%. And in fact increase or decrease ALL the burner dimensions by the same amount. Output changes on a geometric scale I'm not curious enough to figure.

Just don't expect these things to behave exactly, they're close enough for me to work with but I'm a "rule of thumb as a close enough approximation to serve as a departure point" kind of guy. Maybe one of these days I'll bet my lathe moved into the shop and operating and start spinning burners and have to operate by closer approximations but that's a "should" list item.

Oh and FORGET surfing the web to learn anything specific there are just too many people with a connection and cameras who THINK they're experts. If you really want to learn the scientific approximation of perfect you'll need to find maybe take courses at university level. Bernoulli's principles fluidics is a good departure point. If you can do the math and diagram things.

Frosty The Lucky.

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Frosty, I dont get the formula1 thing, honestly... maybe because of my past jobs habit, or simply the way I deal with stuff I use, I cant just look at my tools etc and not think "how does this work and why its built this way?"... I've always done that.
The fact that the net is full of bad advice is another reason for me to try to learn more.

So, for now, I've just asked some questions, some come from reading the "university stuff" and some from material from the net, a lot of which is from this forum, and I really appreciate the help given by everyone that replied.

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Good opening question, but the answer turns out to be another question: just what kind of burner do you mean to apply it do? It turns out that, for Mikey burners, 3/8"  is the smallest size with a full turn-down range. The smaller 1/4" burner can either be turned for a fully perfect flame, or a full turn down range; but not both.

A Vortex burner can be perfectly tuned on as small or large a burner as you can put together.

As to Hybrid burners, Riel burners, Frosty burners, Z burners, and the thousand an one other designs built by people who have looked at an existing burner design, and just started doodling, I think 3/8" on Hybrid burners and 1/4" on mine are the smallest diameters built so far. "T" "Z"  and Riel burners only go down to 1/2". but I think that only reflects lack of interest; not lack of ability.

There are three actual limiting factors for burner size reduction: Lack of use for smaller burners; dealing with the jets become harder the smaller they get; and finally the smaller the burner the harder they are to tune.

I have learned how to use the friction inherent in small capillary tubes to breach the .014" practical gas jet orifice size barrier; this barrier exists not because smaller tube isn't available for gas jets, but because  .013" is the smallest round file found in a torch tip cleaner set.

Fortunately, deliberately lengthening a small diameter capillary tube serves the same purpose as making it smaller:)

Vortex burners have such dynamic flow characteristic that you could probably shrink sizes down to tiny levels, but why would you?

The real limiting factor is practicality. When you drop below 1/4" burners there  are a plethora of propane and butane hand torch already available to choose from for flames that limited.

I think the real question on your mind is how small can you make a burner if you exchange an existing head from one of these torches for a stainless steel mixing tube and flame nozzle for it; the answer is that you have only to look at the endless variety of heads already featured on these torches to know that is strictly up to you.


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Mikey, if I go with one of the forge plans I have in mind I will end myself with a forge chamber of about 300cu/in. Then there would be the baffles when I need a smaller volume. In the other thread you were suggesting two 1/2" burners for that arrangement. I was also looking at ribbon burners, they would work well but I would have to put two in a line and they need the blower too.
From that I was picturing in my head a row of 4 burners, each with its own valve if I wished to not use some of them. Thats why I was thinking about something smaller than 1/2". 

I know this is a blacksmiths forum and that would be the forge main purpose but I wouldnt mind using the forge for some goldsmithing also, the biggest the range of temperatures I can get the more useful it becomes for my work.

If then I can use the burners assembly in open air too even better as it would be useful for some other kind work completely unrelated to metalworking, but that would be only a bonus.


To put a picture to it, the burners would be a sort of very small version of something like this:GS6004.jpg

or similar to two of these side by side with more room between the nozzles: 21389.gif

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vanDoren: The "Formula 1 Burner" is a term Mike coined for burners a person tries to make as high performance as possible. In reply I termed the T burner as an old pickup truck, easy to make, reasonably efficient and reliable. I don't even use my lathe anymore.

It's just a term and you seem a guy wanting to get as much as possible from a device so that sort of makes you a Formula 1 burner guy. A welcome addition to the discussion, more than welcome.

If you're hitting metal with hammers you're smithing be it: gold, silver, red, black or white. Scale is only that, size and what you need for heat is a matter of scale and location. Folk who "Smite metal" is a broad brotherhood.

I recommend you hit garage, yard, etc. sales for a weed burner rather than try making one yourself. I have several I picked up for next to nothing. Of course I accept ,"Just because" as a perfectly valid reason to do a thing. ;)

Frosty The Lucky.

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Frosty is dead on; it is a discussion. We never know exactly who is listening in, and what exactly they are striving for. The more viewpoints get a fair hearing the better matter are for us all.

I wasted several years thinking my way was the best way, and all others were the wrong way. Well, I was wrong; there are as many right ways as there are good reasons for choosing them. If someone can provide you with good reasons for rethinking your path, than heed them; otherwise, forge on.

It is also a mistaken impression that "traditional" blacksmiths don't cast metals; they did so throughout history, and still do today. We get occasional comments on here of how well some smith found his forge turned out for casting in.

With a few minor changes during construction a forge can become a forge/casting furnace; doing both jobs quite well for as large a charge (load) as a single person would want to cast at a time. But for silver and gold, small crucibles work perfectly well in traditional gas forges with only the exception of a hinged door or sliding brick wall added for easy access. Also, you will wont to use a nice hard smooth high alumina kiln shelf for those crucibles to rest on, and slide back and forth over.

Finally, why come to the matter of four burners in a row. Four burners in a brick pile forge can make sense, for heating very large areas. But, with four or even only three burners in a row, difficulties arise with obtaining sufficient exhaust, in an increasingly awkward shape; what to do?

Ron Riel quoted a well known forge maker (in his burner pages) as proposing the idea of lining up individual forges in a row to cure the problem, when it occasionally comes up. I would add that forges with two smaller burners, instead of one larger central burner would do an even better job.

Otherwise, ribbon burners are the only practical solution of very large or awkward forge shapes that I'm aware of, because of their relatively low exhaust speeds as compared to any other high temperature burner.

I do advise you to download a free copy of Gas Burners for Forges. Furnaces, & Kilns in order to view the chapters dealing with subjects like fuel hose, connections, fittings, and mechanical high/low switches. There  are a lot of neat tricks that can be done with them all; and you need to know them more than most guys.

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