Frosty

Naturally Aspirated Ribbon Burner. Photo heavy.

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I use it, so long as I keep it above 3-4 psi it runs for as long as I want to work. I spent about 5 hours last Saturday without a sputter. 

Frosty The Lucky.

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I’m thinking about sawing an inch or so off of my first problematic one once this new burner is up and running just to test for performance changes.  I’m just not so sure if my rotozip with a masonry cutting tool is up for the filthy, filthy task.

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The backburning problem went away when I plugged up a couple of the holes in the burner. 

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More reason for me to cut my burner down!  I’m glad yours is working well.  Perhaps I’ll chop mine down to 1” for the sake of experiment. Would be nice to have multiple functioning burners especially if they serve different purposes.

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19 hours ago, jlpservicesinc said:

Twisted at to low a temperature and the weld shears again depending on what the billet is made from.

Agreed.  I was purely talking about welding temps, not twisting temps.  Two different things.  Stress risers are also an issue to be aware of.  Good observations.

DanR

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Okay, so today I test fired the new ribbon block and the burner was fitted with a .023 mig tip.  It was super quiet and it did have that feedback resonance whistle thing going on.  At lower pressures it burns smoothly but the flames are quite short.  At 10 psi the flames engine the entire forge chamber.

Here's my point for posting:. I'm wondering about efficiency.  If I put the .035 mig tip in would the burner consume the same amount of fuel at lower pressures than the .023 at higher?  Furthermore, would it run noticably richer with the wider jet or does the Venturi draw increase in a straight line on a graph?  I fully intend to experiment with this but it will be hard to gauge fuel consumption.  Plus I would like to go into this with some wisdom in my back pocket.

Thanks for your continued input,

Lou

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There are graphs that'll tell you how much of a given material will flow through a given dia. orifice, pipe, etc. at a given pressure. So yes, you can deliver the same volume of propane through a .023 jet at a higher pressure as through a 0.035 orifice at a lower pressure.

I believe the faster the primary (propane) the greater volume of air it will induce. When you get a NA burner tuned like I like them, the induction curve is pretty straight so you'll have the proper fuel air ratio whatever pressure you feed it. 

That's why I run so much larger jets in the T than so many folk run in 3/4" burners. Mike's run a 0.030 jet so the prop velocity has to be pretty high to induce enough air. Unfortunately faster mixes don't have such a straight curve, raise the psi and air is induced at a greater rate that tends to lean the flame out so there are chokes. 

My philosophy has always been to pack as much fuel air per second as possible in the forge. So when I built a burner that ran lean I increased the jet size. If i't drawing too much air don't choke it give it more fuel. 

Sorry for the sidetrack there, I'm distracted. IT'S R O B O T FIGHTING TIME! 

Where was I? Oh yeah. I don't know what'll happen if you change jets in your burners. I think it's worth the experiment though. My experience which is being proven wrong all the time, says the smaller jet will lean the flames but ribbons are a new world for me so I just don't know.

Frosty The Lucky.

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That was as much as I needed to hear, thanks!  I just wanted to know if my conceptual framework was accurate enough.  I'd like to understand how the additional mixing (and I'll assume slight pressure increase) caused by the plenum and ribbon ports affects the air fuel ratio.  Unfortunately, being colorblind AND inexperienced, I'm terrible at judging the qualities of a burn.  But I shall try 

Thanks again,

Lou

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Here's my very un-scientific opinion/observation on the matter.  If you have the right number of outlet holes so that there is not a lot of extra back pressure then the fuel to air ratio tends to remain fairly stable as you increase pressure. 

However, when I did not have enough holes (or there was too much friction due to longer outlets or anything else that resulted in too much impedance to the flow of the fuel air mix) then what I believe I was getting was an increasingly rich burn as the propane psi increased.  I chalk this up to a restriction on the outlets limiting how much air can be drawn in.  The propane pressure is so much greater that its output will only be minimally affected by the restricted outlets compared to the reduction in air induction. 

If you do not have enough restriction then the flame will burn inside the plenum or switch between the burner block face and the plenum repeatedly, which creates the sometimes startling backfire.

Again, I didn't do anything approaching scientific methods and I did not record temperatures, fuel usage, etc. at different pressures.  It's just my impression from tinkering around with these things a bit.

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I have to differ with you on a point Buzz. What you're doing IS the scientific method. 

Ask THE question, "I wonder what will happen if?"

Give it a try and observe the action. 

Change something and try it again.

Lather rinse repeat till it works or you scrap the idea. 

Taking notes and documenting the process helps but isn't necessary to the scientific method.

Frosty The Lucky.

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Well, I believe my new ribbon block is adding a lot of color into the flames at the moment, so I can’t be sure what is going on right now.  I’ve run it with a .023 and a .030 mig tip and the difference in output at 7 psi is clear.  I get the full swirl in the chamber with the larger jet.  But the swirling flames appear to be reddish/orangish.  I know I had similar colors the last time the ribbon burner was freshly cast.  I’m going to wait until I get some time using the burner and then get some comparison photos.  I know the color of the dragon’s death is telling.  Could I get a little primer on determining the qualities of the flame by color?  Seriously, that would make for a great sticky thread in the section.  I’ve looked for it online but no one seems to have consolidated all that info in one place.

 

Lou

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The calcite in the refractory burns with orange flames don't let it bother you. After it settles down see how the flames coming out the door look. An old trick I remember from photography classes for judging colors is to take shots of a color card with black and white film.  Shoot the object you want to evaluate with the same film and compare to the pic of the color card. We did this a LOT to learn how to adjust tones shades, etc. in BW photos with colored lights and filters. 

It just occurred to me it might help you by removing the colors you can't distinguish from the picture and replace them with shades of gray. 

I don't know if this will work with electronic cameras though, filters and color lamps? Photoshop it if it doesn't automatically adjust color balance. 

I don't know how a burner flame color chart would work, I keep seeing different flames that work very well. Flames I would've rejected and started over with the burner not that long ago. Maybe someone with a better handle than I have. My color vision is going too, that may be part of it. 

Frosty The Lucky.

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I just find myself impressed when some of you gurus see a picture of a burner someone posts and point out, “..oh, that looks to be running a little rich,” or, “that’s a reducing flame you have right there.”   It feels like every gasser here seems to be able to figure it out pretty handily.  I know I could put stock in the forge and watch for scale buildup, but that’s the limit of my knowledge.  Even then I would be guessing.  I guess I’m looking for the fast route toward learning how to tune a burner.  If, in the end, it’s just about feel I’m okay with waiting for experience to guide me.  

 

Edited to add:  after writing this I went ahead and tried some other search terms and found this.  https://weldguru.com/OLDSITE/welding-flames.html

This is the basic concept I was looking for.  I’ll keep reading and I’ll use a picture guide as a reference until my experience surpasses that need.

 

Lou

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3 minutes ago, Lou L said:

It feels like every gasser here seems to be able to figure it out pretty handily.

Calling us gassers, Lou? :o Guess, we can't fool everybody, eh Mike?

I was adjusting oxy acet torches in Dad's shop I don't know when, then at home when he brought a set home to spin hot in the garage shop. Then in all my metal shop classes, on jobs, at home and then we started playing with NA burners around the time the internet went public. I don't know when Mike started playing with gas flames but I have a good idea when Ron Reil did. . . maybe. 

Just the time some of us have played with NA propane burners runs what 35-40 years. After a while I started making mistakes when I try and analyze a flame instead of going with first impressions. 

I don't know about Mike but I started talking about flame colors because it's easier to describe than the properties I find myself judging by and color is more faithfully reproduced by electronic cameras. IF it's in the blues that is. The transparency to opacity ranges can really be distorted, some cameras "see" light we can't and include it. You can download apps for all sorts of color ranges and there's no telling if you're looking at false color images or what degree.

All too often I can't describe what's telling me what when I look at a flame on the screen and too often I'm wrong. Mike has a better eye for it than I so I listen to him, especially when he starts describing what he's looking at and why. 

I wish I had charts or rules for analyzing flames . . . <sigh>

Frosty The Lucky.

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I used a forge this weekend that was running a multi port burner using a ceramic foundry filter for the face (3/4” T burner).  We ran the forge for at least 6 hours with no backfire. I’ll post a picture from the manufacturers website below of what the filter looks like. 

He only used one filter about 2” square so there was still a hot spot in the forge. I think two of these stuck together with some furnace cement would make for a nice burner face and spread the heat a little better. So far I’ve only been able to find these for sale by the box. With the smallest box being 100 count. 

It also has me wondering if anyone got anywhere with using the ceramic barbecue  blocks. I saw a test burner a few pages back but no final product. 

 

 

 

C6DD5238-D28A-4CCF-92A9-C52250A1AFFB.jpeg

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0214191721i.jpg0109190939.jpg                                                                        I have not visited that project in a bit. although i am thinking of building a heat treat oven with 1/4" burners that may power these little bbq plates. 

the pic is of a 1/2" if i remember correctly.

I didnt tinker enough to get the ratios right but it is definitely doable. I am concerned of thermal cycling cracking. Maybe a Kasto 30 soaked ceramic wool layer over the face might help?

 

On 7/9/2019 at 7:41 AM, Jbradshaw said:

foundry filter

that looks ideal

On 6/28/2019 at 10:18 PM, Frosty said:

IT'S R O B O T FIGHTING TIME!

such a good show!

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Wow, there have been a lot of posts on this thread since I was last here. It looks like people are really refining their designs for burners. Anyway, here is an update on my  (very primitive looking)1” NARB...

I’ve been meaning to write this for months but for various reasons haven’t been doing much forging lately and wanted to wait until I’d at least used my new forge a bit before I reported back. I’m also struggling to find any pictures as my phone that I used for pics and videos has since died, but if I find any I’ll add them later on.

So, I built a forge out of an old 18kg propane bottle with the customary 2” of ceramic wool and a refractory layer to seal it. It’s a big heavy beast. I then made a burner with a 11/2x11/2x1” T-piece, 8” mixing pipe, 9” x 2” plenum and 40 outlet holes done with the crayon method. I can’t remember the size of the mig tip I used right now but I initially tried a smaller one better suited to a 3/4 but it didn’t have the mojo to run the larger burner so it was soon swapped for a 0.9mm or 1mm tip.

The outlet hole number seemed to be bang on, no back burning or blowing out. The only issue was that there was a lot of dragon’s breath with a blue tinge so I got the impression there wasn’t enough air in the mix. I tried grinding the mig tip back a bit but it didn’t make any noticeable difference so I swapped the T-piece for a 2x2x1” and used a 10” mixing tube. This seemed to do the trick and while there was still dragon’s breath it was at least a healthier orange colour. The sums might not make sense to those of you who are mathematically inclined (ie that’s a lot of air and mixing) but hey, that’s what seemed to work.

The burner ran fairly well and would tick away at around 4 psi although below this and it would quite often start to backfire. I also found that as it heated up after about an hour I would need to start cranking up the pressure to prevent backburning, as is to be expected.

The downsides of the build are what you would expect - the forge takes some heating up, and by the time it’s properly hot I’m usually done with what I was making, but that’s not a reflection on the burner. I’d like to give figures on temperatures and times but, ironically, my thermometer sensor caught fire so can’t (I’m pretty shambolic and probably shouldn’t be allowed near large cylinders of explosive gas). I didn’t attempt to get to forge welding heat and maybe with the wick turned up it would, but I’m not entirely convinced it would get that hot. Maybe the forge is a bit of a heat sink.

Unfortunately, when I went to fire up my forge the other day the burner just kept backburning and igniting gas in the T-piece. Not wanting to die in a massive fireball just yet I now need to build another one. On inspection the burner had cracked, which I suspect means it is leaking and so the whole thing is lacking the pressure it needs. Why the block has cracked I don’t know, but I suspect I had it sat too low into the forge and that it would benefit from being retracted a bit back up into the forge liner. I used the highest temperature castable I could find from a major company for the block and the liner, although the liner has cracked a fair bit already. I didn’t use any heat reflecting wash (I forget what it’s called) due to not being able to find any that I didn’t think was silly expensive, but I might look into it for my next build. Speaking of which - time to make a smaller forge with a 3/4 burner tube.

So basically, a 1” tube NARB is just as easy to build and it works. Whether it is worth it over making two 3/4 to run a large forge I don’t know, but it might make you happy. I don’t have figures on gas usage as mine didn’t last that long and I didn’t take any notes but I suspect mine was a thirsty beast.

There you go, more grist for the NARB mill. I will try and find some pics and add them later. Thanks to Frosty for his input.

 

 

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Shambolic? Great term, consider it adopted, that's the secon today. One of the guys in our club is still looking for his, "Forever Anvil."

I've built 1" burners but it's tough fitting them to the forge properly, all that heat is in one place and its hard to turn it down low enough. I think your excessive "dragon's breath" is an example of too much burner for the volume. Even a ribbon would have similar issues. With 2 burners in the same volume you have much better temperature control, you can shut one off for serious curn down. 

Nice story but I don't see any pictures. You don't REALLY expect us to believe it without pics do you? :P

Frosty The Lucky.

 

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