3D printed plastic burner experiments (photo heavy)

[D.Rotblatt]

 

On 12/29/2019 at 9:23 PM, Another FrankenBurner said:

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

I like that!  Have you tried putting your injector on a ribbon burner?  I'm (slowly) working on one with 3/32" holes instead of the 1/8" to replace my forced air ribbon burner (which broke - not a design flaw, cracked while modifying it). Hoping the 3/32 holes will not "sing" as much.  It's kind of a hassle lighting up the forge. I'm also going to try using a shorter mixing tube, as it's going into a plenum which should allow for more mixing.  Like that flame blade though!  Out of the box thinking!

DanR

[Another FrankenBurner]

I have not dabbled in the ribbon burners much yet.  I am still playing with burner geometry in the simple burner to learn as much as I can.  I am close to feeling satisfied with that and once I do, I look forward to adding to the list of variables with the ribbon burners.  I will fully appreciate the lower volume everyone keeps bragging about.  (Except for you and your singing forge)

Shortening the mix tube is worth a shot.  If it mixes properly in the plenum, your throughput should increase.  I wonder if the fuel/air needs to be pushed down the restrictive tube to mingle well.  Maybe that is why the 8-9 rule of thumb is around?  It seems like the violent change in volume and direction would be good for mixing but every commercial unit I have seen, has the full length before the multiport.  

We'll see where the flame blade goes.  I like the idea of one in a forge but they are a pain to get balanced.  In the mix tube, the mix is spinning.  It doesn't like to go long and narrow.  I did get it to work and it looks great.  

[671jungle]

11 minutes ago, Another FrankenBurner said:

I wonder if the fuel/air needs to be pushed down the restrictive tube to mingle well.  Maybe that is why the 8-9 rule of thumb is around?  It seems like the violent change in volume and direction would be good for mixing but every commercial unit I have seen, has the full length before the multiport.                                     

Introducing color to a running stream comes to mind reading this. The two travel together for a time before they become a solution. 8-9 may be the sweet spot 
 

[D.Rotblatt]

On 1/15/2020 at 9:41 PM, Another FrankenBurner said:

It seems like the violent change in volume and direction would be good for mixing but every commercial unit I have seen, has the full length before the multiport.

It's a good point, commercial units do have a long mixing tube first.  Just to add more variables, I also wanted to play with the nozzle size - basically on my singing NARB the 3/4" mixing tube fits into a 1" tube which is welded to the plenum.  I found that it really made a difference how far the 3/4" tube was inserted into the 1" tube; it ran best with about a 2" length of 1" nozzle before the plenum.  My thought in my next one is to weld a 1.25" tube onto the plenum, insert a 1" tube into that and the 3/4" mixing tube into that so I could play with the the nozzle length and ID by sliding the tubes in or out.  It could either be a single step up from 3/4" to 1.25", or two steps up from 3/4" to 1" to 1.25" of varying lengths of up to around 1.5-2".  Unfortunately I won't get to play with the burner until late February as I have a knife show coming up and need to make some new inventory.  I've got the plenums and molds all ready for 100 holes @ 3/32".  Sigh...so much to do.

DanR

On 1/15/2020 at 10:01 PM, 671jungle said:

8-9 may be the sweet spot 

Only way to find out is to try it! 

[Another FrankenBurner]

I thought about the telescoping pipe setup for mix tubes.  Approximating a tapered mix tube with steps.  Never actually tried it though.  I am playing with smooth tapered mix tubes now.

I look forward to your updates.

[Another FrankenBurner]

I finally dusted off the printer and have something to report here.  I got distracted playing with ham radio again.  Here is my latest flame:

It's not perfect but it is tiny:

It is coming out of an eighth inch(nominal) burner.  I thought the quarter inch burner was small.  Rocking a 2.25" long mix tube.

Mikey and Frosty have mentioned the smaller the burner, the more critical the build.  It is apparent with this little guy.  Using printer nozzles as orifices, 0.4mm runs purple lean and 0.5mm runs a tad rich.  If the nozzle overhang is changed a 1/16th of an inch either way, the flame lifts off or goes rich.  It is picky but I got it to run stable in it's narrow range.  It sounds like an angry little jet.

I finished turning down all the 3D printer nozzles into burner orifices and thought I should attempt to use some of the smaller ones in a micro burner.  Since this guy likes around 0.45mm orifice, imagine the burner that would use the 0.2mm orifice.  I am already gilding the lily with this one, I probably won't attempt a more critical smaller build. 

Being so critical, I am going to be tinkering with this guy.  I am experimenting with nozzle shape to see what I can learn and hopefully extrapolate improvements to the larger burners.  

[Frosty]

"AFB's Angry Little Jet Burners." Has a nice cadence doesn't it? 

If you take this a little farther you'll be needing Waldos to make and tune them. 

I'm watching for the tooth brush size multiple orifice burner. 

Joking aside I'm in awe, you're rocking the home built micro burner scene. 

Frosty The Lucky.

[Brijasher]

Excuse me a minute. I need to find my jaw and a mop for the drool.

-B

[G-son]

1 hour ago, Another FrankenBurner said:

It is coming out of an eighth inch(nominal) burner.  I thought the quarter inch burner was small.  Rocking a 2.25" long mix tube.

You mean 1/8" schedule 40 pipe? Actual internal diameter 0.405" or 10.3mm.

Looks very nice! I'm planning a ~10mm (probably linear) burner for hand held use, and was expecting around 0.4mm printer nozzle to work (based on data on Mikey burners, they seem to like jets about 4% of mixing tube actual diameter), so you have confirmed I'm probably in the right neighbourhood so far. 

[Another FrankenBurner]

Thanks Frosty.  I'm already playing with bits so small that if I drop them, they go into the abyss. Waldo work sounds like it requires a good deal of patience.  By multiple orifice burner, are you talking about a micro NARB?  If so, that had not entered my thoughts but now I am going to have to give it a try.

40 minutes ago, G-son said:

You mean 1/8" schedule 40 pipe? Actual internal diameter 0.405" or 10.3mm.

1/8th" schedule 40, yes.  Though 0.405" is the OD.  I got tired of looking up the chart, then cutting the diameter in half and then converting to metric so I made a spread sheet. 

The ID is 0.269" for 1/8" pipe.  I got the calipers out and my pipe is at an actual of 0.264" so it is close.  Anyway, I am running 6.7mm at the 0.4 - 0.5mm orifice but my burners tend to run with a larger orifice.  If you are talking about a 10mm Mikey burner, the 0.4mm sounds like a good starting point.  Wouldn't it be great if your 4% observation holds true?

Every time I guess, I am wrong.  I have a trial and error collection.

Thanks for asking, my model was based on the chart not on actual so I have updated my model.  Every little bit counts and 5 thousandths probably matter.  

As I was writing this, I heard my printer finish printing.  It was printing another 1/8" inducer head with a change.  Here is the new version:

I trust my printer and this was a 1 hour print so I just clicked print and ignored it.  I walked into this.  Good for a laugh.  I wonder what size orifice it needs.

[Frosty]

Now THAT'S a mixing tube! I'd like a look at the blue print.

Frosty The Lucky.

[Another FrankenBurner]

That's top level secret stuff.  I shouldn't have even posted a picture of v88.  Prior art and all that.

[G-son]

2 hours ago, Another FrankenBurner said:

1/8th" schedule 40, yes.  Though 0.405" is the OD.  I got tired of looking up the chart, then cutting the diameter in half and then converting to metric so I made a spread sheet. 

The ID is 0.269" for 1/8" pipe.  I got the calipers out and my pipe is at an actual of 0.264" so it is close.  Anyway, I am running 6.7mm at the 0.4 - 0.5mm orifice but my burners tend to run with a larger orifice.  If you are talking about a 10mm Mikey burner, the 0.4mm sounds like a good starting point.  Wouldn't it be great if your 4% observation holds true?

Ah, you don't just have to find the right chart, you need to read the right column too! Running 0.4-0.5 in a 6.7mm tube is even more impressive, it says something about how good that design is flowing air. (We already know that it's great, but still, worth pointing out again!) 

That last design of yours might work better as fuel than as a burner part.

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. If I had a metal lathe it would be relatively simple to get all the pieces to line up, but with a drill, an angle grinder, a hack saw and some files I will no doubt have alignment issues no matter what route I go. Anyway, the goal is a burner in a size that a hand held gas bottle is able to feed, but larger than the store bought hand held burners I already have (~5mm mixing tube diameter). Something in the 8-10mm diameter seems resonable.

[Mikey98118]

The inside diameter for 1/8" schedule 40 pipe is about 1/4". But the inside diameter of schedule #80 1/8" pipe is about 3/16"; a very important difference for more than  one reason.

While very small diameter drills are more than merely frustrating to use for enlarging miniature gas holes with, piano  wire does pretty well  at enlarging hole diameters in copper and brass; just a thought

The fact that you have produced such an excellent flame on a 1/8" burner is quite a feat; that it also has a good turn-down range is even better. Congratulations, once again

[Another FrankenBurner]

Any particular reason you want a larger torch on a hand bottle?  Somewhere in the burners 101 thread is a picture of a 3/8" Mikey on a bottle.  I wonder how quickly it can drink the whole bottle.

Ron Reil has a 1/2" hybrid burner with a pistol grip as a shop torch but it is on a hose to a large source.  I used it a few times for flame bluing.  It was handy.

Thank you Mikey.  

[G-son]

The hand held small burners I have are great for silver brazing small items, heating aluminum engine blocks for bearing replacement, and many other kinds of general heating. They're portable, I can just throw them in a backpack along with other tools when I go to repair something at a friends house. I also have a oxygen/acetylene welding set for the times I need more heat, but the size and weight makes it mostly stationary, and it's illegal to have in an apartment anyway (and lets not get into what it costs to refill the gas). I want a burner that fills some of the gap between those two options, something portable with better heat output, with at least five or ten minutes runtime before the bottle freezes.

I did build a 18mm linear burner using the smallest MIG tip a year or two ago, the smallest easily accessible gas jet (at that time) seemed like a good start for testing. Works nice, but a hand held bottle freezes after about two minutes at full blast - kind of useless with that time limit, but I've learned a lot from it. I'm thinking if I go to a 8-10mm burner it should consume roughly a quarter of the gas the 18mm burns, and in theory it should take at least four times as long to freeze the bottle, i.e. 8 minutes or more at full power, and with the newly "discovered" smaller 3D printer nozzles burner builds in such sizes should be quite possible.
Not perfect but such a burner should be good enough, I think I use the small torches 5 minutes or less most times - and that's the size I have now, more power output should make many of the current jobs faster.

[Another FrankenBurner]

Ah.  I understand.  I purchased a Bernzomatic TS8000 long ago for more output.  I used to run Map-Pro(propylene) but now I just run propane.  

I built a small linear burner run off a small bottle six or seven years ago.  It was a Reil burner fashion with the hand drilled cross tube.  Made from stainless tubing and copper fittings.  

I look forward to your build.  

[Another FrankenBurner]

Been so busy enjoying the forges, we haven't spent much time on R&D.  I have a couple of burner experiments which will be showing up soon but we worked on forges.  3D printed forge forms have turned out awesome and now we are again after the unicorn forge.  Or maybe we just like lots of forges.

Here is the latest mini and big'un.  

Of course, we have already thought of possible improvements we are plotting on the next one.  We are also going to do an in between size as the 3/8 burner can handle it.  

I have long wanted to play with the idea of a split forge with a bottom mount burner but securing the refractory in the top portion has been our biggest hurdle.  

Here is a burner size line up:

[Mikey98118]

I consider a 1/8" propane burner to be the smallest size that could be considered practical, as blue flame butane torches have already perfected miniature needle flames. Congratulations

[ThomasPowers]

On the bottom burner system---how are you going to keep crud from falling into the burner tubes?  Or will you just remove them and shake them out after every use?

[Another FrankenBurner]

Thank you Mikey.  I mostly made the 1/8th inch to see if I could.  I imagine the forge it could support would be tiny even by my standards.  Nail makers forge.  

Thomas, the bottom mount burners I have done are in the round edge pointed at 45° ish.  I also build with the wider floor space so I keep the metal away from the burner port as much as possible.  I have not had a problem with stuff falling in.

Here is a previous post with a shot of one of the bottom mounted burners

 

[Mikey98118]

On 4/13/2020 at 12:11 PM, G-son said:

You mean 1/8" schedule 40 pipe? Actual internal diameter 0.405" or 10.3mm.

That is the pipe's outside diameter. .269" is the nominal inside diameter of 1/8" pipe.

"We are seeing the same issue with the K26 bricks that we had with the K23's."

Are you sealing the hotface sides of those K26 bricks with a good hard refractory coating to keep their vary porous structure from flame damage?

[Latticino]

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...

[tinkertim]

Hey AFB,

That is a cracking micro-burner!  Very impressive.

I've been meaning to ask you which CAD software you use for your 3D printed injectors.

I've been using a free one called Designspark Mechanical for many years.  It is a cut-down version of a powerful package that RadioSpares (RS) sponsored and offered as truly free tool, but with the option of using free 3D libraries of the parts they sell on their website.

I've used it a lot for various 3D printed parts, as well as designing the re-layout of stud-walls in a utility room.

The reason I'm asking about what you use, is that I was trying to work out how I would go about designing the twisting vanes for an injector without having to do lots of "lofting" to allow the vane profile to twist correctly. I wondered whether other free tools would be better at it.

Keep up the great work!

Tink!

[Another FrankenBurner]

Mikey, I sure didn't refractory coat the bricks.  I coated some in Matrikote 90AC but I did not butter the brick when applied so it pealed off in short order making it a poor test.  I intended on kastolite facing one but we made the kastolite/blanket half bricks before I got to that experiment.  The kastolite bricks are so amazing for my uses that I never looked back at the K26 bricks.  The 4 replacement kastolite bricks maybe took 5lbs of kastolite and have outlived an entire case of Morgan Thermal Certamic K26 bricks.  A case of bricks costs more than a 50lb bag of kastolite where I am. 

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.