Frosty

Naturally Aspirated Ribbon Burner. Photo heavy.

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Welcome aboard Vincent, glad to have you. If you'll put your general location in the header you might be surprised how many members live within visiting distance.

Thank you for the information, I THINK that's where we were going, it certainly fits in with it. 

Dan: I'd have to go out and measure it but I THINK mine's around 400 cu/in with two ribbon burners driven by 3/4" Ts. One side is open with partial baffles so it leaks a lot of heat. 

Lou: I keep coming back to more pressure and keep your burner blocks cooler while increasing the velocity of the FAM.  Nothing about your forge or burner jumps out at me as being wrong or even odd. Dan's thought about maybe several things combining or multiplying to make a problem makes sense. That way no one issue may be apparent as it's several. Maybe.

Frosty The Lucky.

 

 

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The forge is 5.75 inches in diameter.  All told, including the 3x3 column at the back entrance, the forge is about 290 cubic inches.  I was concerned that back pressure might become an issue.  

Ive considered more variables I could test in order to deal with the pressure.  Changing the length of the mixing tube is one option.  Changing the mig tip is another.  I figure that, once I play with the ports on the burner block, I will test each of those as well.  Any other ideas?

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Yeah, that sounds like back pressure could be the issue. It's on the small side and kind of narrow. 

No MORE variables, stick with the pressure till you've eliminated it as THE problem! Turn the pressure up say 1 psi per test and don't stop till you've exceeded 20psig.

Leave the burner ports alone, blocking a couple demonstrated that higher mix velocity helps if it isn't THE answer. BUT blocking outlets isn't the easy nor logical FIRST way to speed it up. The regulator is, turn it up. There's nothing magical about running low psi. some guys have just obsessed over lower is better for some reason. It is NOT better if your burner doesn't work better. You've put a lot of work into your burner find out where it runs best and put your forge to work. 

One thing Lou, change just one thing at a time until you've eliminated it. You're killing me looking for MORE variables to worry about. Now STOP that! 

Don't make me come down there and smack your fingers with a ruler! :o lol.

Frosty The Lucky.

 

 

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Maybe on the way to Quad-State?

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Lol.  I promise to not change variables until the current test is complete.  I certainly could test with higher psi and see how much it takes to run smoothly.  At some point, though, I will be pushing as much heat out of the forge as I am keeping in.  Once I get a number on the right psi I want to change another variable on oredrr to see what allows me to run more efficiently.  My goal is to learn what makes these burners tick as much as it is to make this one work.

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On 4/11/2019 at 10:56 PM, Frosty said:

Welcome aboard Vincent, glad to have you. If you'll put your general location in the header you might be surprised how many members live within visiting distance.

Thank you for the information, I THINK that's where we were going, it certainly fits in with it. 

 

Frosty The Lucky.

 

Thanks for the welcome Frosty. This Forum is a goldmine.

I'll get onto adding info to the header. 

Vincent

 

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10 hours ago, JHCC said:

Maybe on the way to Quad-State?

Maybe, we'll have to see.

Frosty The Lucky.

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I got a little tinker time in today.  I used half a IFB and then cut that down by about an inch, which gave me a depth of about 3.5 inches for the burner block.  Using a piece of a computer case where there were vent holes for a template I drilled 1/8 inch holes in the IFB.  I believe I ended up with 68 usable holes in the 2.5 by 4.5 inch burner face.  A few holes were a little too close to the edge, so I filled them in with refractory cement.  Then I built a plenum from an old washer door - around 16 gauge I think.  The plenum is 3.5 inches deep and the brick is inserted about half an inch in and then sealed with refractory cement.  I fed the burner with the same T burner setup I used in my previous NARB (3/4" schedule 80 pipe and .023 mig tip).

For the open air test burn I had quite a bit of flame lift under 5 psi, so I could probably use more holes, but I'd have to go longer since more holes would weaken the IFB too much I fear.

Once in the forge the flame lift was minimal while the forge was cool and of course there was none once the forge was up to temperature.  I ran it up to high yellow, nearly white heat for about 20 minutes or so and then turned it down.  I was able to turn it down to the point where no pressure was showing on the regulator and no backfires at all.

There were a couple interesting observations.   Like Dan's forge, mine "sang" to me when I started it up.  The sound was somewhat similar to the noise you get from blowing across the opening of a bottle.  It changed with pressure from the regulator and how much the front opening was blocked off.  After the forge was up to temperature the noise went away.  In general though, this thing is really quiet.  My previous NARB was loud by comparison.  The only thing that is louder is the bang when I shut off the fuel.  That was significantly louder than I was used to.  The plenum stayed cool the entire time the burner was running and  was still cool a few minutes after shutdown when I checked it, but that's not too surprising since my burner is floor mounted and facing up.

I don't expect the IFB burner block to last long.  This was basically a proof of concept exercise for me.  I may get some of those Morgan K26 bricks to see if it's a viable option.   Personally I'd rather drill holes than cast a burner if I can get good results.

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That sounds promising alright. Frankly I'd rather drill if I can get reliable results too. If K26 IFB can take the heat for extended use casting blocks would be doing it the hard way for poorer results. Hmmm I wonder how small a hole I can drill in K26 bricks?

Cool results, thanks Buzz.

Frosty The Lucky.

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I've had good results with my drilled K26 IFB NARB (Buzzwords!!!). The new forge I'm building for it will be faced with D.Rotblatts Collidial Silica Investment slurry, mixed with Zircopax.  I'm going to use this to treat the flame-face of my driled IFB NARB, to see how it hold up to the heat, long-term.

I'll post up results.

Tink!

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Tink: If you pinch your nostrils and say NARB over and over you sound just like a bulldog with a head cold barking. :lol: :lol: :lol: :lol: 

Frosty The Lucky.

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A British Bulldog!!! :) 

NARB!, NARB!, NARB!

(and I do have a head-cold at the moment! :( )

Tink!

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It's like I can read minds. 

Frosty The Lucky.

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On 4/16/2019 at 4:56 AM, tinkertim said:

I'm going to use this to treat the flame-face

I use it on ifb on the forge floor in my small forge. It does strengthen them quite a bit. Seals cracks too. 

Look forward o seeing how it all comes together!

Dan

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I'm just getting going with all this (burners, forge, etc.) but I have a working linear-injector burner in nominal 3/4" size with a standard nozzle, and parts ready to assemble a 20-lb-tank forge.

I'd like to try the ribbon burner. The drilling-a-firebrick approach seemed interesting so I played a bit with a glass/tile bit; it seems possible but will take a while and also seems tough to get consistent holes. So then it occurred to me that a 3d-printed core might work well for casting a nozzle. PLA apparently burns out well for lost-PLA casting, so I am currently printing a core for my first attempt. I have some of Wayne Coes' castable refractory intended for ribbon burners on order. I went kind of large, thinking I can plug nozzles if I need to increase the nozzle velocity. The core is 138 nozzles over an 8"x2.5" opening, each 4 mm (0.157") diameter with a taper out to 5.6 mm (.220") over the last 7.6 mm (.299") (the nozzle dimensions were for a 6deg expansion, but that's the half angle so perhaps too much?). It's still printing, 18 hours in at this point. It looks like the finish may be a little rough but I'm excited to experiment with these things. I'm hoping I can get the refractory packed around the core okay; I may print a tamping tool that fits around the core pillars. The plan is to burn out the PLA in my forge with my existing burner, though I suppose then I'll have to modify the forge to accept the ribbon burner if that's the direction I want to go.

1115230085_IMG_0808(Medium).thumb.jpg.a3950f9783672578cf0cfb036ecbef0a.jpg

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Looking forward to your results.  A tamping tool may be helpful to get the refractory where you want it, but vibrating the whole mold form before the refractory begins to set up should help give you the best results.

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1 minute ago, Buzzkill said:

Looking forward to your results.  A tamping tool may be helpful to get the refractory where you want it, but vibrating the whole mold form before the refractory begins to set up should help give you the best results.

Thanks. ...thinking about how to rig up my little air hammer to vibrate the mold...

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I used my pneumatic needle scaler but found drilling a 1/4" hole off center in a small piece of scrap a short bolt and a couple nuts chucked in my hand drill worked nicely. I duct taped the drill motor to the bottom of the wood mold so I could gently rod the Kastolite between the outlets. 

Frosty The Lucky.

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I had trouble getting the refractory between the rods due to the large grit in it. I used mizzou. Had to push little bits between the rods with a thin knife blade. PLA is brittle, so be careful. You may want to try to sift the dry refractory through a screen to remove larger particles. Vibrating didn’t work for me..,the grit was too big/space between rods too small and by the time I got enough refractory between the rods it was starting to set up. It was worth it though, my burner is great!  

I don’t think you want the rods to flair for a ribbon burner.  I was thinking of doing the opposite to push the flame away from the block and keep it cooler, but it doesn’t ever backburn, so not necessary.  

Great use of 3D printing!

Dan R

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Can't remember if I noted a couple of weeks ago that I plugged a couple of the holes in my NARB with kaowool, and drastically reduced the backfiring-at-low-pressure problem. I may block one more (or change which ones are blocked), as that does seem to have created a slightly cooler spot in the middle of the forge and/or a slightly hotter spot at the back (although I freely admit that that might be a function of the internal pyrodynamics).

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My experience is much like Dan's, I think I've mentioned sifting the aggregate out of Kastolite and rodding it between the crayons. I vibrated it aggressively AFTER getting the refractory to the bottom of the molds. The vibration causes small aggregate to settle into spaces and voids between larger aggregate and corners AND causes air bubbles to rise to the surface. The mechanics of vibrating a concrete in this manner is to literally cause liquefaction so the mix can flow downwards and bubbles and excess moisture can be driven up and out.

Rodding down is an art, too much force can make things worse, the aggregate particles are all crushed material so they WILL key together and form bridges and caverns with the spaces where material may flow in to fill them blocked by smaller particles keying together. Rod gently, if it fights you, STOP and go to vibration or a mallet. A mallet should be applied laterally, no more than one or two HORIZONTAL blows on each side. Do NOT work opposite sides, work around the mold 90* impacts do a better job of dislodging key'd particles.

Getting good flow of refractory into the mold is my main concern with using lots of small outlets in the same size burner face. You're getting darned good results Dan, what sieve size are you using? I just used a kitchen colander. 

Frosty The Lucky.

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14 hours ago, Frosty said:

 I vibrated it aggressively AFTER getting the refractory to the bottom of the molds

Didn’t sieve it, just a recommendation now. Vibrated the same, even though it had started to set up. Didn’t get bubbles, so it still worked.  So far only made the one with small holes. But I  will try to seive  it on my next (I have another really old bag of mizzou). Planning to redo my forced air burner block with 1/8” holes...i think I can fit 250 holes on a 8x2” plenum in a 12” long x 6” diameter forge. 

Dan

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I'm kind of torn right now. It's warming up enough to cast some refractory and I have a forge idea I want to try but it needs some flame velocity if it works at all. On the other hand I want to see how one with 13x +/- as many 1/8" holes and a thin block will work. I wonder what they'll think at the local convenience store when I take a pair of calipers to their coffee stirrers. 

Fun stuff.

Frosty The Lucky.

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4 hours ago, Frosty said:

I want to see how one with 13x +/- as many 1/8" holes and a thin block will work

Go for it!  Would love to hear how your version works!  Of course, you could do both....

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