3D printed plastic burner experiments (photo heavy)

[Mikey98118]

6 hours ago, Latticino said:

If you are getting into this level of precision I recommend switching to tubing rather than continuing to work with standard ERW pipe.  Tubing has much closer production tolerances...

And tubing comes in seamless versions, are closer to round, have much more wall thicknesses available, and are stocked and cheap in stainless.

[Mikey98118]

On 4/13/2020 at 5:19 PM, G-son said:

I'm leaning towards a linear burner as I've read they tend to work better than mikey burners in small sizes, but I have not decided yet. It's not so much a matter of what burner style I want to build, as what design I can make work with the tools and materials available.

You heard right. My first bottle-mount Mikey burner was 1/4" size, and so finicky I discarded it, and built a 3/8" size for the hand torch on the Burners 101 thread.

[G-son]

If Mikey himself was not able to get the 1/4" Mikey burner to work good enough I find it unlikely that I would have any better results with it. I actually was planning on building a mikey style ~1/4" burner first (adapted to the materials and tools I've got, so perhaps not a true mikey burner) just because I figured out how I could build one of those first and it seems to be relatively little work, but based on what you just said it seems it would most likely be a waste of time. Looks like it's indeed going to be a linear burner first.

[tinkertim]

4 hours ago, Another FrankenBurner said:

tinkertim, thanks for the good words.  It is a neat little toy burner.   Software wise, so long as you don't mind tinkering , you are in luck.  I am using FreeCAD.  It is a full featured package which kind of works like Fusion360.  It is clunky by comparison, free and all.  Once I figured out how to work with it, I have no problems producing models.  You probably work in metric so that is perfect.  I am working with pipe, in standard.  Swapping FreeCAD into standard mode is a bad idea, weird things happen.  So I convert between metric and standard constantly.  

Cheers for the info AFB.

Tinkering?  It is literally the story of my life!

I might have a look at FreeCAD, but I guess as I'm pretty skilled with the Designspark Mech tool (we also use it for pulling in PCB designs to ensure they fit inside custom cases, etc.) I think I'll continue to play with the "clunky" I know rather than learn a new clunky. 

I'm thinking of making an approximation of your 3/8" burner to use as a hand-held torch, and may design a simple pistol-grip into it, purely for some lock-down activity, and because its tiring trying to dial a 3/4" AMAL burner low enough to use as a paint stripper on a steel garage door without going through the door!

Cheers matey.

Tink!

[Mikey98118]

46 minutes ago, G-son said:

f Mikey himself was not able to get the 1/4" Mikey burner to work good enough I find it unlikely that I would have any better results with it.

To be clear, I got it working right. "Right" wasn't satisfactory in this size.; it just wasn't worth the effort.

[Another FrankenBurner]

We've been pretty focused on forges and burners again.  We are very excited about where it is all heading.  The forges are starting to function and look awesome.

I've been spending a lot of energy on learning more about nozzles. 

This work has payed off.  Here is a 205in³ forge with a 3/8" burner running with a 1mm(.0394in) orifice:

This is at 5 psi.  It is so bright it is unpleasant to look into and created all the glares on the camera lens.  We are referring to it as the super burner currently.  At 20psi, this burner is loud and angry.  At 25psi we activated the excess flow valve using a 40 lb propane cylinder.  

The main thing which is so exciting about this is the tiny burner size.  My first forge had a 3/4" modified sidearm burner which stuck out like a great moment arm to constantly be hooked or bumped.  Here is a picture of that sidearm and the new burner for comparison:

 

We have several forge liners casting.  We are also gearing up to cast burners again.  We built a thermocouple rig to be more consistent with our pouring temperature.  The foundry got a burner upgrade.  We built several more flasks.  We are having all kinds of fun.

[Frosty]

Uh. A 0.394" jet in a 3/8" burner is crazy big, that's about what I run in a 3/4" T. You are efficiently burning as much fuel per second in a burner 1/4 the size. As measured by the area of the cross section of the mixing tube's throat That is just awesome induction. Have you measured the forge temp? 

I expect you realize that burner is WAY too much for that little forge it needs to be in 350 cu/in or it's going to start melting liners. 

I mean, oh HOLY MOLY WOW!!!

Frosty The Lucky.

[tinkertim]

That is just EPIC AFB!!!

It seems from my perspective that not only are you developing some of the coolest(NOT!) burners and forges out there but it seems that you are having great fun while you are doing it!

I am in awe!  Keep having fun my friend.

Tink!

[Mikey98118]

I agree with the others. You're on a roll.

[Another FrankenBurner]

We did not measure the forge temp after it reached 2300°F so that we didn't damage the thermocouple.  If only the exotic thermocouples weren't so expensive.

I do realize it is too much burner for the forge.  We saw it's performance outside of the forge and it got us excited... impatient.  So it temporarily made it into the nearest forge which happened to be this guy.  We haven't played much.  It's low end is below 1 psi so I plan on seeing if it can be dialed back far enough to function well with this forge.  After that, it will go into a big forge to see what it does with that.  

With the 1mm orifice, it is running a purplish flame.  We tried a 1.2mm orifice and we had some green show up.  We've been playing with FAM ratio attempting to determine the point of too much oxygen to see what the flame looks like.  Mostly watching shined metal for scale formation.  

[Frosty]

I got an IR laser thermometer for the kitchen, -4 to 608f. It's handy for getting the temp right frying and the griddle. It'd probably be good for tempering and I found out the temps of various parts of the wood heater. 

Do they make one that reads more than 3,000f. that costs less than launching a satellite?  

I REALLY want to see one of those little demons connected to a ribbon burner.

Frosty The Lucky.

[G-son]

What about those cones used in kilns to tell temperature, I'm thinking they could be used to see what max temperature you can reach? Perhaps not very useful for everyday work, but for finding out the absolute max, or making a chart where different gas pressures are compared to the temperature achieved. I'm assuming they're cheap, as they are consumed when used.

https://en.wikipedia.org/wiki/Pyrometric_cone

[Another FrankenBurner]

I am not sure about the laser thermometers.  I think I remember reading that they can't be trusted at the higher temperatures.

I think I have said this before, but I'll say it again and maybe it will be true this time, I think I am close to satisfied with the inspirator tinkering.  For now.  After that, I will move on to ribbon burners.  I am looking forward to playing around with them.  I have several experiments already planned.  A quieter burner sure sounds nice.

The cones are a good idea.  Ron Reil used to use them to test.  I would love to know the maximum temperature that these burners are pushing but I don't want to push the forge refractory that hard.  I was pushing it when I took that photo.  The only exception maybe being when we cast the iron pieces.  It is tempting to crank it to 20 psi to see what happens.  Maybe I could get some nice elephants foot photos to post.

[jlpservicesinc]

That is really great work..  

[HojPoj]

On 6/8/2020 at 11:51 PM, Frosty said:

Do they make one that reads more than 3,000f. that costs less than launching a satellite?  

Different method of reading, but wouldn't a pyrometer used at a foundry get you a better estimate of the forge temperature without breaking the bank?

[yotebuster1200]

On 6/8/2020 at 8:53 PM, Another FrankenBurner said:

With the 1mm orifice, it is running a purplish flame.  We tried a 1.2mm orifice and we had some green show up.     

So I have been thinking about your jets. You should use some hex main carburetor jets.  Yoi can get them anywhere from .6mm mutch past 3.0mm.  The best part is they come in about .025mm increments.  For instance you can buy a 1mm, 1.02, 1.05, 1.08, 1.1, 1.12, 1.15, 1.18, 1.2.  

 

With these jets you should be able to fine tune your burners a little easier.   I have ordered a set that goes from .6 - 1mm in .05mm increments and plan on ordering another set that goes from .8- 1.5mm (ish) in .025mm increments.  

 

In another post you mentioned that you get a tighter burn with the 3d printer nozzles when compaired to the mig tips.  I wonder if it is because the triangle shaped tip which somewhat matches the shape of the top cone on your indection zone (where the 3d printer tip rests).  So it might be worth grinding the carb jet into a similar profile so you have the shape.

 

Ok now for a question,  when you say this burner (which is absolutly incredible) is a 3/8 burner where is this measurement taken, is it .375 (or probably nominal 3/8ths at the location where the burner enters the forge, or is it the measurement at the narowest point in the burner assembly (the bottom of your mixing cone)?  What is the widest part of the burner.

 

Nice work on these burners and forges.  

[Another FrankenBurner]

The foundry pyrometers which I have found are using K type thermocouples with a 2300°F limit.  We have built one of these for our foundry but the forge exceeds this limit.

I like the available options with carburetor jets but the assortment kits that I have found are all fairly expensive ($150).  I purchased a 24 piece 3D printer nozzle assortment for $7.  You are right, the carburetor jets would make dialing a burner in much easier.  The price is right on the printer nozzles so I tune the burners to work with the available orifice sizes the best I can.  Did you find an inexpensive set?

The tighter flame of the printer nozzles vs the mig tips is because of fuel ejection velocity.  Mig tips have a longer restricted section which slows the fuel down more.  I connected both types up to water to test this idea and the printer nozzles ejected water almost twice the distance.  

If I went to carburetor jets, I would grind the cone shape into the tip though.  It probably does not make much of a difference but I streamline everything I can.  The one exception would be using pipe with a welded seam.  The weld seam makes a difference.  It disrupts the vortex and shows in the flame.  I've held onto the pipe burner thing because I like the homebrew history of it but tubing is an obvious easy way to improve things. The first few 3D printed burners used thin wall tubing.  

When I said it was a 3/8" burner, I was using the standard pipe burner designation.  The throat of this burner matches the 3/8" pipe used as a partial mix tube so it is nominal(0.493"). 

The widest part of the burner is the ejection point which is 1.25" which is fairly large.  The throughput of this burner is high and because it is 3/8", it is short, so the fuel mix is racing out of the mix tube.  It required a large aggressive step up to slow it down enough.  

[yotebuster1200]

I kind of figgured the difference between the 3d printer jet and mig tips might be the length of the orifice.  In the fire fighting industry (and probably other industries)  we call that friction loss. You lose pressure the longer a fluid (gas) flows through a tube of a given diameter. The smaller the tube the more friction loss you experience.  

[Mikey98118]

The other side of the coin is that friction loss in capillary tubing can be used to fine tune the burner by sanding off a few thousandths of an inch in length at a time; something that isn't going to apply with a printer nozzle. This isn't a dig against printer nozzles; I'm for them. But...the right choice for every problem means not limiting our choices.

[HojPoj]

On 6/14/2020 at 12:25 AM, Another FrankenBurner said:

The foundry pyrometers which I have found are using K type thermocouples with a 2300°F limit.  We have built one of these for our foundry but the forge exceeds this limit.

Oh, I meant the non-thermocouple one.  It's actually a sort of handheld optical comparator.  You actually tune the brightness of a bulb inside which is calibrated to a known temperature, when you look through it and the brightness of the furnace and the bulb matches, there's your temp! 

[SnowdragonIW]

On 12/30/2019 at 12:23 AM, Another FrankenBurner said:

Here was one of my nozzle experiments a while back.  We call it the flame blade.

This is wonderful! I was wondering you had any more information on this one? I was thinking about building something very similar but was wondering if you had any ratios or data for this kind of burner? I was initially thinking that the area of the opening (nozzle, nozzletts, blade?) should be 1 to 1.25 the area of the tube but this one looks like this one has a larger ratio? 

I was also wondering what happens if you 'force' air into one of your burners. I was was thinking  having a plenum around the top. I am guessing it would blow the flame out? or could it make your already impressive burners burn hotter? 

Sorry but one more if you will indulge my exuberance, but the one with the nozzle cast into the refractory, did you reinforce that at all? I would be worried that it would crack in the area around the nozzle?

[Another FrankenBurner]

I can give you more information about that one small set of experiments with the flame blade.  No general ratios though.  I didn't play with it enough to get to that point.  It was such a pain to dial in the first time that I haven't dialed it in to the newer burners yet.  It produced a very neat, wide, short, quiet, clean flame.  I had intentions of having a single burner deliver a flame over most of the length of a forge.  

It is a finicky balancing act.  First, the area of the ejection point is important, like you thought, because it controls where the flame rides.  Too much and it sucks back, too little and it lifts off.  This was all I initially thought I had to get right.  I didn't think about the vortex in the mix tube.  On the outlet, we will call the longer dimension the length and the narrower dimension the width.  If the width is not constricted enough, the flame will flop about from side to side because it is a tornado going to the point of least resistance.  Constrict the width enough and I think the two opposing sides sort of cancel each other out and it comes out wide and mostly straight(semi laminar ish), but then the length has to be modified to match the required ejection area to prevent suck back into the plenum.  The problem is, that area has to be restricted to the point that the fuel/air mix(FAM) is coming out too fast to prevent lift off which requires another section with a larger area(nozzle).  

I'm not done with it yet, I have some other ideas to try with the concept, but streams flow better through round sections.  Which is why I will probably move on to ribbon burners.  So many ideas, so little time.  Right now, all efforts are on successful casting of the heads, forge design and a treadle hammer build.  We are getting closer on all of that.  

On 7/13/2020 at 5:53 AM, SnowdragonIW said:

I was also wondering what happens if you 'force' air into one of your burners. I was was thinking  having a plenum around the top. I am guessing it would blow the flame out? or could it make your already impressive burners burn hotter? 

My burners were designed to induce and mix air into the fuel without external power aside from fuel pressure.  If air is supplied, most of the geometries I worked hard on finding, are no longer important.  Forcing air into my burners could allow for a higher output but it would probably cause the flame to lift off, as you thought.  The nozzle would have to be enlarged to match the flow.  I suspect at some point it would have problems with mixing the the extra FAM.  I may eventually play with a powered burner for a larger furnace but I suspect it would be quite a different beast all together.

As to making my burners burn hotter, that is a fun question.  The short answer being I don't know, probably not.  The long answer brings up a lot of questions.  Hotter as in flame temperature or forge temperature?  What determines the temperature of the flame?  What determines the temperature of the forge?  What does flame temperature have to do with total output? 

I remember seeing a tube video a bit ago in which someone made a pipe burner ish and posted it.  He had a wildly rich, 3 foot long, yellow sooty flame.  He took this to be a good thing and was all excited about a big ole flame.  What he had was a very cold flame.  It took 3 feet to attempt to burn all of the fuel.  If his flame was hotter, it could burn the same amount of fuel in 3 inches.  A hotter flame is burning faster, in less space.  The energy density is higher.

All other things being equal(ambient temperature, FAM temperature, fuel composition, etc), as far as I know it, flame temperature is dependent on the ratio of fuel to air and how well they are pre-mixed.  Not enough air(reducing), the fuel will not burn completely to liberate all of it's potential thermal energy.  Too much air(oxidizing) serves to cool the flame off and we are injecting free heated oxygen into the forge to oxidize our work.  If the FAM isn't pre-mixed well we could deliver the cooler reducing flame along with the free oxygen.  The bad of both worlds.  The right ratio of thoroughly pre-mixed FAM will burn as hot as possible, while completely using the oxygen.  In a perfect world. 

Since it is not a perfect world, I consider the perfect ratio to be a fine line between reducing and oxidizing which I can not accurately measure or consistently hit.  Also, because perfect pre-mixing doesn't exist, I suspect the flame probably lives a little hotter on the oxidizing side of the line to a certain point.  Extra oxygen to crash into the free fuel so it will burn more completely.  However, I follow the advice of many, and usually live on the lightly reducing side of the line because it keeps free oxygen from chewing up my work.  I have been experimenting with how far I can push towards oxidizing before I notice scale build up increasing.  

Fun huh?  Most of this doesn't matter much.  You want a higher temperature flame, get close on the ratio and mix it decently.  There are big signals if you are not close.   

Flame temperature isn't everything.  What if you have the hottest LPG flame on earth and your forge isn't hot enough?  A mini torch type lighter has a hot flame but it won't heat a big forge.  Why not?  The flame is hot, we just don't have enough of it.  If we had a higher volume flame, even if it were 200° cooler, the forge temperature would be hotter.  This has it's limits.  

So I've likened the temperature of the flame to density of energy and the size/amount of the flame to the volume of energy.  The product of these two make up the total energy output, or the mass if we follow my analogy.  So if we have a higher temperature flame, we don't need as much of it to equal more of a cooler flame.  This total output is often given in BTU's for commercial burners. 

In our burners, this number changes as we change the fuel pressure.  Fuel pressure changes change the fuel volume and the air volume.  If they don't change at the right rates, the FAM ratio could be changing as the pressure changes.  This could be changing the volume and the temperature.  It is easier to draw in more air with more fuel pressure so several burners lean out their flames as the pressure is increased.  I don't like this so I spent a lot of time changing things to prevent it so I could adjust fuel pressure without having to adjust a choke. 

What about forge temperature?  A forge is nothing more than a temporary container for all this energy.  If we have the flame out in the atmosphere, the heat quickly dissipates.  If we try to heat our work directly with the flame, most of the heat will rush right past the metal to also dissipate in the atmosphere.  Inject heat into an insulated container and it will hang around a little longer and heat up the walls to a high temperature.  The container leaks(loses) energy at all times.  The higher the temperature difference between the forge and ambient air, the higher the loss.  During initial heat up, the energy input is higher than the energy lost.  As the forge heats up, it loses faster.  Eventually it hits a point where the energy in matches the energy lost.  This is our maximum forge temperature for those conditions.  If we want higher temperature we can add insulation, decrease the forge volume, increase the flame volume and/or increase the flame temperature.  Decrease the forge volume?  Who wants that, besides me?  If we can increase the flame temperature, great.  We get as close to the fuel temperature limit as we can and all we have left is increasing the volume.  Eventually we can hit a point where there is so much volume that we are blowing heat straight through the forge and out the door.  We are just wasting fuel at that point.  So we have our temperature as high as possible and our volume dialed in, our forge will never exceed our flame temperature.  Lucky for us, the flame temperature limits of LPG blends are a bit higher than we need so we don't need to be able to hit the limits to have a usable forge.  

So the long answer is, I doubt I can get my burner flame much hotter.  Even if I did, I may not know it.  I don't fully know where in it's tuning it is at it's hottest or what it's maximum temperature is.  I have control of the fuel/air ratio and I think I am mixing decently.  It's the best I can do which is more than enough for me.  I don't think I've had temperature improvements in a while. All of my later improvements were increases in their volume capabilities which just means I can output more with a smaller burner.  

That was probably more answer than you were looking for but I was thinking out loud(?) so I rambled on.  Hopefully it all makes sense.  My mind runs faster than my fingers.

On 7/13/2020 at 5:53 AM, SnowdragonIW said:

but the one with the nozzle cast into the refractory, did you reinforce that at all?

If you are talking about the forge with the nozzle cast directly into the forge liner, there is nothing special to reinforce it.  It is a test to see how that situation holds up.  We have other tests in which the refractory nozzles are floating to see how that does.  We have a specific forge in mind and so we are testing the refractory to see how we can pull it off.  

[Frosty]

Nicely said Curtis, good precis.

I usually look at the volume of FAM per second that can be burned IN the forge as the measure of effectiveness of a burner.

A FAST burner may be both hotter and produce more BTUs but doesn't hang in the forge long enough to transfer as much energy to the liner as a slower cooler flame.

I should've prefaced the above with "in MY words" but what the hey. 

I'm still watching for the next improvement. 

Frosty The Lucky.

 

[SnowdragonIW]

21 hours ago, Another FrankenBurner said:

That was probably more answer than you were looking for but I was thinking out loud(?) so I rambled on.

I am so happy right now! This was not to much information. In fact it has me re thinking several aspects of my forge and the burner I am thinking about building. Thank you so much!  I have so many more questions now but they are half formed. 

And yes I was talking about the forge with the nozzle cast directly into the liner. My step father was a stone mason and I was remembering that he favored a "Fiber Mesh" product added to the "mud" when he was making fireplaces/chimneys. It was a fiber glass like product that he said reduced cracking and helped reinforce the cement. My inital thought was that if you mixed something like that in with the refractory it might extend the life span of the liner but then I remembered that you could melt glass in the forge and that might do the exact opposite. I know that it is also kinda common to reinforce with steel (rebar and other such products) but you might end up with a similar problem. I was wondering if there was something we could add to the refractory to reinforce it? If not I guess we are all "doomed" to be rebuilding our liners/forges periodically?  The other side of that thought was that it looked that the thickness around the where the nozzle was a little thicker than the rest of the liner. It seems that the different areas would cool at different rates and maybe cause cracking. Have you noticed any of this or am I just too new to refractory and erroneously importing lessons that my stepfather taught me that only apply to cement?

[Frosty]

Masonry is masonry though different cements, plasters, etc. can be wildly different. The "fibercrete" additive for refractories are high temp stainless steel needles and serve the same purpose.

Frosty The Lucky.