Naturally Aspirated Ribbon Burner. Photo heavy.

[Frosty]

Oh YEAH, now you're burning in the ball park! Still a LITTLE rich but darned close. Have you read my T burner build posts? They'll lay out tuning methods that work. Burners 101 also lay out good if different methods, including a burner nozzle flare that works well I didn't realize I was using. 

A 1/2" NA burner lives almost perfectly in a forge volume of 150 - 175 cu/in. 

Do NOT worry about PSIG, it isn't important for getting a good burn. The ONLY time PSIG matters is for repeatability so you don't have to remember how the flame looks to make the forge a particular temperature. We don't always need incandescent yellow heat, sometimes it can do more damage than good. Thin sections can be melted right off before the thicker section reaches useful forging temps for example. 

I'd scrap that forge and build one from the plans in the forges 101 section. The less heavy refractory in the fire the less fuel and time it requires to heat the . . . forge. 

Frosty The Lucky.

[Doc Peepaw]

I had some leaks in the last one at the plenum refractory junction so I rebuilt it.  This one came out much nicer aesthetically. 

I sprayed the pla mold with WD-40 for a release agent and the sprues pulled out without any incident. 

I also cast a new forge body.  I realize by making it of refractory and being so thick it will take some time to heat up, but it should make it more resilient to travel.  I am looking forward to firing it up this weekend but it still has some drying and a coat of ITC-100 to go before that. 

The volume comes out to 155.455 in³.  It should be a good weekend. 

[Doc Peepaw]

If I do have to make another ribbon burner mold, I need to extend the sprues or tines or whatever you want to call them and make them stick above the level of the edge of the mold.  I had to drill out the holes to get air flow through them.  Learning is fun.

[Frosty]

That makes it easier. I'm surprised you got WD 40 to work as a release agent, I had to settle on sticky grease to keep the refractory from actually bonding to the mold.

Kudos Doc, let's all keep learning!

Frosty The Lucky.

[Doc Peepaw]

I fire up the forge yesterday.  It does take forever to heat up because of how thick the refractory is but it seemed to be working well.  

Since is was still running slightly rich I decided to try amd tune it for a more neutral flame.  I ground a bit off the tip of the MIG tip, put it back in and now, for some reason it is running super rich.  I didn't get any pictures but something went bad.  I wanted to keep working on the problem but it got really cold and I was coming down with something, so I stopped for the night.  Still a little under the weather and it's still cold so I don't think I'll get to troubleshooting what went wrong until some later date.   I'll post pictures of how rich it ran next time I'm out in the shop.

[Buzzkill]

This may seem a little counterintuitive, but I'd start by making sure the mig tip orifice was free of burrs and debris.  We shorten the tips to help induce more air, but if there is any restriction or deflection of the fuel stream it can have the effect of inducing less air.   If you did run a torch tip cleaner or something similar through the mig tip I guess it's possible you increased the orifice size a bit which could produce the effect you are seeing.

Another thing to check is the axial alignment of the tip with the mixing tube.  Sometimes things don't get lined up when we replace the tips as they were before we removed them.

P.S.  I know it's just a photographic perspective thing, but your first pic looks like the back wall of your forge is the propane tank and it's glowing. It made me shudder a bit when I first saw it.

[Doc Peepaw]

Ha, that would make me shudder too.  No, it was a fire brick.  It also had another wall of fire brick between it and the tank.  I do some stupid things in my life but I've seen too many of my friends blown up to want to blow myself up.

That said, I did run a tip cleaner through it.  The issue was, most likely, a small leak at a junction which was lowering the pressure at the MIG tip and thus lowered the mixture of oxygen.  

I took out some superfluous parts and re-tooled the attachment of the MIG tip to the T burner.  It was slightly crooked before as I tapped it by hand.  Now that I've got a lathe it made tapping straight much easier.

The extraneous parts

the new attachment 

I've, since this picture, ground the MIG tip back a bit more.  I think I'm still having an issue with velocity.  I figured out the my area with the 41 1/8 inch holes is roughly half what you, Buzzkill, have with your 14 9/32 inch holes.  So I'm printing another mold to cast another burner with 14 9/32 inch holes.  Should be ready in a few days to try out.  

I also am continuing the build.  It needs a lot more insulation.  I'm going to build a box to surround the refractory so I can have a minimum of 3 inches of kaowool above it.  The bottom is only going to have 1 inch of kaowool under the refractory which will hopefully be good.

Despite all that I was able to get bordering forge weld temps with only 1 inch kaowool draped over it.

I didn't get as much done working on it this weekend as I had hoped as I came down with a case of the 'vid.  I still managed to work on it but man was it tiring when breathing is difficult.  I am looking forward to trying the different burner.

[Buzzkill]

I had forgotten how many NARBs I've fiddled with in the past few years.  One of them I made which was fed by a 1/2" Frosty T setup used 1/8" holes drilled into an insulating fire brick.  I believe the number of holes in that one was in the high 60's and I concluded it could have used more holes.

The one I'm using now has 44 holes that are 13/64" in diameter, but it's fed by a 3/4" Frosty T burner system.

I'm interested to see how your next one turns out though.

I really liked the idea of the floor mounted burner in a D shaped forge, and it did perform well, but the loss of so much floor space changed my mind so I went back to a side mounted NARB for my latest build.

[Erik Mendel]

I don`t want to necro post; however, I have some questions and maybe some relevant input to this topic. I have read this thread well over 5 times in my efforts to make a new narb forge. I've watched Ron`s you tube videos and seen every thing I could about the variations which have resulted due to frosty`s initial sharing of this great innovation. I have recently copied frosty`s design`s (more or less) first with t-burners and flares and then put his ribbon burners into the first stages of testing. note- due to some of the reported burners heating and burning back into the plenum when running for longer times I increased the mass slightly in the hopes that the extra refractory would allow the gasses to keep the plenum cool enough to minimize the burn back.

This is the first time that I have built a t-burner (4 actually) when I initially did my research to decide what I wanted from my forge I decided to copy the Ron Reil modified side arm burner. I chose this due to my reading something from frosty stating I think that his burners would start to huff at psi less than 5. I run my burners with an idle circuit for normalizing at next to off. The slightest adjustment would kill the burner and the 1/4 dial is adjusted 1/16 to raise or lower forge temps by 5 or 10f deg.  I have used side arms in my main forge for 4 years now and run a thermocouple to help alleviate my inexperience at telling the correct colours. Due to the chokes on the side arm burner I use my main forge with a muffle pipe to hold steady (3deg fluctuation-usually due to wind) down to 1350 for heat treating. The side arms are running .23 tips. This does give a lean burn however I found the price of propane to be prohibitive enough to warrant using the wire wheel to clean more often. 

I made the 19 crayon holes in a 3X8 block of mizzou, the internal holes layout I think would be roughly the same as Frosty`s (2x7?) original design but with more castable surrounding the holes, and thicker metal -1/4 inch tube and 3/8 side walls. My intent was to hopefully be able to run the ribbons using the choke on the side arm at much lower than the 5psi without burnback. Today I was able to run the narbs out side the forge at 3.5 psi and adjust the flame quite a bit with the choke, not the t-burners mind you. Im not sure how much the back pressure will change these results but I have some questions of the fore fathers in the hopes to point me in the right direction.  I ran 6 different burners today (2 side arm and 4 t-burners changing mig tips .23, .30 and .35) and switched between 6, 8 and 9 inch mixer tubes. I found that the burners which ran on the side of lean would run out side the forge only between 5 and 8 psi above that they would blow off the face and burn unevenly( 5-10 holes only) the same burners with .35 tips would run even further off the flame face and not even run out side the forge unless the setting were exactly within certain parameters. The side arms I started with initially had .23 tips and preformed poorly until I put the .30 tips in, I was able to start the burners at 3.5 psi and adjust the air input to change the ratio in most cases to have all of the burner holes run through out the ranges of lean and rich and 2-15 psi. Is this capable for a properly tuned T-burner ( did i just do a terrible job of centering the hole?)  in a narb or is it only because of the side arm? Is this only because I am doing testing outside the forge?  based on what I saw today I hope that my initial dreams of having a narb to run 1500 holds reliably without burnback could be successful. I'm interested to hear of any other things I should try in an attempt to assuage weather or not this experiment has actually changed the potential of narb performance.  

[Frosty]

6 hours ago, Erik Mendel said:

Is this only because I am doing testing outside the forge?

No Erik, that isn't the ONLY fundamental error you're making. It IS however a real game stopper. 

My advice is to tune your burner where you're going to use it. 

Stop changing several things at once and expecting to have any idea why you can't predict the results or what caused them. 

Stop trying to tune to psi. Once you have it tuned it'll be stable at almost any psi available through a quality regulator. Mine are all stable stop to stop through my regulator. Stop to stop means turning the adjustment screw all the way in or out. 

The way you're trying to "tune" a NARB is like saying you tuned your engine to run at sea level in 90 degree weather but it doesn't run right at 10,000' at minus 20 so I changed my trailer hitch, psi in the tires and tail light bulbs but the heater still isn't defrosting the windows. 

Pick ONE proven burner and NARB and stick to THAT set of plans. If you're going to use it in a forge tune it IN THAT forge. PERIOD.

Frosty The Lucky.

[Erik Mendel]

Thank you sir in the forge will be the rest of my experimentation, I do recall reading this advice from your self to many other individuals and feel stupid that you have to continually repeat your self to the new guys.  I might be mixing up the difference between the frosty on its own and the frosty with the narb. what I wanted to know was do the t-burners run well at lower psi, I tried today to run the t-burners with some Zoeller flares and found them to be great above 5 psi am I mistaken that they have been having issues below that? as to the narbs with t burners, I recall your pulling them further back and solving the burn back issues after 4-5 hours was around 6 psi? please don`t take these questions in anything other than the light they were intended- my intent is to fully understand where the rest of the group is and hopefully contribute something useful  to the community

 

[JHCC]

I’ve run mine down to about 2 psi. 

[Erik Mendel]

Mine are all stable stop to stop through my regulator. Stop to stop means turning the adjustment screw all the way in or out.

 

Burners on their own or with narbs?

 

I’ve run mine down to about 2 psi. 

gottcha, I totally misunderstood then, your running narbs or t-burners/ flares

[Frosty]

Sorry I was so harsh Erik, new guys ask the same questions and make the same mistakes, it's not really a big deal. I just have grouchy days now and then. 

I don't run a flare on T burners, I use a thread  protector as a cheap easy step flare. I started using them as sacrificial nozzles rather than burn up the mixing tube nipple. The tread protectors are free at the HVAC supply service up our road. 

T burners are notoriously sensitive to back pressure or breezes, forget them working in an honest wind. However he thing that really delighted me with NARB is a T powering one doesn't give a fig for external breezes they've proven stable in 10mph+ gusty winds. 

There is no flare as such feeding NARB but I weld a thread protector to the plenum and just screw a T on. So maybe it has the thread protector step flare. Maybe they don't work that way on NARB I don't know.

NARBs burn back running below maybe 6psi. I don't recall specifically. The nozzlet blocks I cast are too thick so it takes that much flow to keep it from heating enough the flame front velocity drops below the flow velocity.

In plain English that means the block gets hot enough the flames burn back to the plenum and then it all catches fire. There has bee a lot of discussion about "flame front velocity" AKA, Rate of propagation. Rate of Propagation" is how fast gas burns in still air. The flame flashing along the still gas is the "Flame Front."

When I say gas in still air I mean a flammable mixture or it wouldn't burn. Yes?

I haven't made another NARB since the first two. Other guys here have taken multiple outlet burners WAY farther and faster than I could have. I'm pretty out of school anymore. 

So please do learn all you can and improve on the things, I'll be happy to read your instructions and try new things.

Frosty The Lucky.

 

[Erik Mendel]

oh frosty I take no offence from your candor, this is the reason that ifi has been able to benefit from what you have shared  with the community. I feel as though you have pioneered this adventure and have nothing but respect for the time that you took to share with the community and help us to benefit from your experiences.(and how well you laid it out for us- the t burner instructions as well as this thread) I guess I should ask more clear questions sorry 16 hours of work and 8 beer me was clearly excited.

1) is it normal for forges to reliably run at 1400f deg (understanding well enough the standard expectation of surface area 350 per 3/4 burner, 2 inch kao wool, 1/2 inch kast 30 and IR reflective {hyb,matrikote,itc} normal standard for good forge efficiency)  if yes then which proven burner has been doing this for you.

2) if people have taken this much further then you (frosty) then whom do you speak of. I recognized the ceramic burner attempt ( I believe Ron on utube?) and thought it was very promising until it failed approaching welding temps.

3) I am very concerned with psi because I have been running 2x3/4 burners for 25/50 hrs a week and propane is getting more expensive. While I was running .23 tips in the side arm I would run 9 psi for 2100 -6 hrs minimum.  Today I ran T burners for the first time with .35 and achieved 2000 at 6 psi (unconfirmed which is costing more to run but very interested in finding that answer). I guess the truest test of efficiency would be to run each at a set psi for a set time and weigh the difference in tanks then compare. Side note maybe not important- when I shut of one of the side arms the heat drops back to the side of the burner and only heats maybe 6/8 inches (round forge 6"x 13") of the forge making the working space so small I've never felt the expense is worth the money. I will say this: today when I shut off the frosty with .35 tips it continued to heat almost the whole forge space to reasonable working lengths (almost the whole forge) at 6 psi and still ran 1900 deg. This realization has cut my propane expense in half instantly which makes me extremely happy. 

I understand that this whole dialog maybe should be in the burner section; however, my interest is in getting the most efficient and even forge heat I can and I believe that narb is the most likely road to this goal.  

I'm sorry frosty!! side arms are also horrible in the wind less than 3psi is not realistic with any gusting wind

[Frosty]

I'm glad I haven't offended you but that doesn't excuse my being cross with my reply. If I can't be polite I shouldn't say anything to paraphrase my Grandmother and Mother.

Agreed, fatigue and beer aren't the best learning tools. 

Back on topic. I just developed the multi outlet burner by copying ones commercially available and adapting them to a home built inducer. It didn't even take that much experimentation.

What triggered it was watching videos and seeing pics of blown ribbon burners blowing 2'-3' of flame out the doorways. Sure they got steel HOT but all that fuel burning OUTSIDE the forge wasn't doing anything productive. Unless you WANT to heat the shop with carbon monoxide!

Burner output is a function of the AREA of the mixing tube's ID, the same rule applies to the jet. A 0.035" jet is about 50% larger dia than 0.023" jet for more than 2 x the area so of course it uses 2x the fuel so it should heat 2x the forge volume. No?

Here's the rub. A smaller dia. jet relies on a higher velocity to induce combustion air so the flame velocity is higher meaning it spends less time in the forge transferring energy to the liner.

It wasn't until Mike pointed this out in a way that made me think about I realized the T burner with it's double air intake ports and large jet makes it a low velocity burner so the flame stays IN the forge longer. Being slow makes it more efficient, not any particular clever trick. 

This is where the multiple outlet burner really shines. (If/when I make another one it is NOT going to be a ribbon, it will be a button or ring burner) Multiple outlet burners make small flames which do two good things.

1, they decelerate quickly in the forge so if you don't get crazy with the inducer, be it NA or blown, the flame stays where it can do work for you. 

2, and directly related a longer stay in the chamber means all the fuel and combustion oxy have a chance to burn completely where it works FOR you.

Well O K A Y. 3, multiple outlet burners can be tailored to heat exactly what you want heated. Ribbon in a heat treat oven. Perfect. Ring for spot heating long stock. Button for heating wide areas, etc. I have trouble not getting silly stupid carried away with tailoring the things. 

Latticino IIRC has made sweet multiple outlet burners with 1/16" outlets and IIRC even smaller. It makes for VERY soft slow flames. My dented head doesn't recall the names of the other guys in the forum who've made excellent versions. Some with drilled brick some with various really high fire ceramics, one anyway with SS. burner blocks. 

Don't get hung up on efficiency, you're looking for EFFECTIVE. They're not the same thing.

If you're really concerned about economy you should consider an induction forge. They use no electricity unless they're heating steel. They heat quickly, require short soak time and you can control precisely where the heat goes. You don't see many guys doing it but you can make different induction coils, loops, pads, wands, etc.

At these inflated fuel prices the break even point for the up front cost of an induction forge and propane savings wouldn't be very far down the line. Hmmm?

Frosty The Lucky.

Edited March 21, 2022 by Mod34
Typo

[Erik Mendel]

so much good information thank you frosty!

[Frosty]

You're welcome Erik, it's my pleasure.

Frosty The Lucky.

[Hefty]

On 7/28/2019 at 5:03 AM, Howling dog forge said:

OK so time for the dog to say some crazy stuff, I am pondering the possibility of using dura board  refractory for the "core" of the ribbon burner with a Kasto lite 30 shell and/or face surface. Drill the dura board, put in the plugs, put a level face on it with the plugs in place and when all is cast pull the plugs soak the holes with rigidizer and reinsert the plugs to keep the surfaces of the holes as smooth as possible. This makes the burner much lighter, and hopefully not as inclined to transfer heat to the plenum. And of course making a 1/2" layer of Kastolite/Mizoo fill around the plugs will be a lot easier than forcing it into a rather large heavy brick.  

TL;DR: Would ceramic fibreboard with stainless steel straw inserts work?

I had a thought, did a search and found this. Howling Dog, did you ever end up trying anything like this? I've recently found a local refractory supplier who sells ceramic fibreboard. I was thinking of buying and cutting up some cheap stainless steel drinking straws and either drilling and inserting or punching them into place in the board (not sure how tough the board is) and then putting a flame face coating on the outside. I know there have been some concerns over pre ignition if the stainless inserts got too hot, but I thought I could cut them a little short, so the fibreboard is taking the brunt of the heat. There were also concerns about stainless inserts causing cracking in cast blocks due to different expansion rates, but I figure the fibreboard would have a little more give, maybe?

What do people think? Would this work? Do I just need to "suck it and see"?

Cheers,

Jono.

[Buzzkill]

I did something quite similar to what you're describing.  It's documented here:

https://www.iforgeiron.com/topic/68753-another-narb-experiment-pic-heavy/

It worked fairly well - at first anyway.  Ultimately the refractory box cast from sifted kastolite 30 cracked badly, so I moved on to another idea I had.  Towards the end of the time I was using it I kept getting burn back into the plenum pretty much right at welding temperatures.    If I stayed in normal forging range it would work indefinitely without issues.

[Hefty]

That's where I saw that image! Thanks Buzzkill. That's what I was searching for. I have questions about the fibreboard because I know where to get it, but I haven't worked with it, so I don't have a feel for its characteristics.

Does it drill cleanly? Or if I used SS drinking straws, would they "punch" into it reliably, or would there be punch-out on the back of the hole?

You mention burning in the plenum at high temps/pressures. Do you suspect this is from the sleeves getting too hot? Your pic was what led me to think of SS straws, although I don't know if thinner metal would mean it would heat up faster, or be more readily cooled by gas flow?

[Goods]

I’ve not worked ceramic fiberboard. Would it be possible to file teeth into the SS straw and use it as a hole saw? Maybe even lightly tighten the toothed straw in a cordless drill’s chuck to make it easier? I could be way off base, but I’m curious about this.

Keep it fun,

David

[Hefty]

That could be a good option. Thanks David!

[Frosty]

If you back the board on something solid say oak tan leather on wood bench it shouldn't blow out much if at all. Experiment though, at least once. 

Frosty The Lucky.

[Buzzkill]

On 11/1/2022 at 5:03 PM, Hefty said:

Does it drill cleanly? Or if I used SS drinking straws, would they "punch" into it reliably, or would there be punch-out on the back of the hole?

It drills ok with high speed on the bits, light pressure, and a wooden board to back it up.  You want support under it to avoid punch out. Slightly undersized holes are ok as that helps hold the tubes in place, but I think trying to punch holes without any drilling would most likely make a mess of the boards. I'm not sure about filing teeth on a straw.  It might work, but if not done well it could result in more of a tearing than cutting action.

As far as the burn back into the plenum goes, I'm not entirely sure.  There were several things going on.  As I mentioned, the box I cast cracked, and that may have created an additional pathway for plenum ignition.  Also with less than an inch between the plenum and welding heat, it's possible that the board itself allowed enough heat through to be an issue.  I think I still have the block I removed.  If I remember in the next few days I'll try to take a look at it and see if there is any obvious heat discoloration on the SS inserts.

Overall I do think the concept works ok, but with the extreme temperature swings we produce in small forges the challenge is finding materials that can handle the extremes without cracking. 

Now you've got me wondering if I could make the "box" out of fiber board as well and use high temp mortar to glue it all together and glue it to the plenum.  I'm fairly sure it would handle the swings in temperature without cracking, but the board doesn't really bind to adhesives well since it can delaminate somewhat.