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I Forge Iron

Naturally Aspirated Ribbon Burner. Photo heavy.


Frosty

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  • 1 month later...

Decided to play with my narb today.  Plugged 3 holes and it worked very well.   So I insulated the forge and rigidized it.   Waiting for kastolite to show up and I’ll get it finished up.  Had 21 holes and 19 after plugging 3.  Tried plugging 2 and it did burp a few times.  With 3 plugged it was stable down to 5psi

EB986B1D-02D0-4D0E-B709-BE1936E0C801.jpeg

52BA7A3C-ABCE-4D5E-94E3-BD8BF65DF7FE.jpeg

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  • 2 weeks later...

Looking good. Looks to be running a bit rich maybe a LITTLE more trimming is called for, no good reason to generate more CO than necessary. With the burner mounted horizontally any chimney effect will be very  minimal and ribbon burners don't make a lot to begin with even mounted vertically. You can attach the rubber propane hose directly to the 90 fitting on the burner without worry of over heating and put the valve at the other end of the hose. 

I've tried the 1/4 turn ball valves I use at both ends of the fuel circuit and it makes so little difference as to be none. 

Altering the propane circuit isn't so important, you have it well thought out and I see little chance of problems as is. However I do recommend you do a little fine tuning and get your flame closer to neutral, Carbon Monoxide is bad stuff, it takes something like 80x as long to flush out of your blood as it takes to replace O2 molecules bonded to your hemoglobin. Extreme poisoning may require a stay in a hyperbaric chamber.

Even if your shop is well ventilated, CO can effect you and folk around you. Sorry to go on but I get jumpy when I see such a rich flame, I don't have so many friends I can afford to lose one without saying something in prevention.

Frosty The Lucky.

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Lol that’s a typo.  18 after plugging 3.   

I will trim a little bit at a time till it neutrals out.   

I dout co can build up in my shop with 3 walls but why chance it. 

Flame is more blue in person but the camera always changes the color   

For some reason you can’t even see all the flames in the pic

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A TYPO!?!:o <gasp> I keep hearing about typos but . . . I'm no longer much embarrassed by missing a key stroke but they make great straight lines for a born wise guy like me. 

You might consider opening one of the outlets you've plugged but I'm up in the air on that, I really HATE changing more than one thing at a time trouble shooting a problem. I still think the inducer needs tuning but opening the flow a LITTLE will reduce back pressure and shorten the flames.

Still that'd be two changes and. . . :unsure:

I don't just look at flame color. I look for the degree of transparency in specific flame envelopes and your flames are opaque light blue in the outer envelope which says "Rich" to me. The outer envelope should be nearly transparent dark blue, some guys are hitting invisible or non existent outer envelopes which is running to the "lean" side. My personal preference is SLIGHTLY reducing to minimize scale formation in the forge

Jer

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I haven’t plugged the holes permanently yet.  Just stuck some chunks of 1/4” round in the holes for the test.   I do believe your right about trimming the mig tip as it is a bit long/past center slightly.   I’ll play with the tip and get it running a little more closer to neutral before I come back to the nozzles holes.  

Thank you for your input. 

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  • 2 months later...

Finally got a ton of time off, getting back to this. I've got 2 sets of 14 holes on either side of center, I didn't drill the center two holes instead of using a diffuser (tho as frosty noted he didn't use one anyway) seems to be running ok for now. I've got to get a mock up made of my forge tonight so I can stick this in and see how it runs inside the forge. So far it looks ok to me, unless someone smarter than me sees something amiss I'll keep plugging away

IMG_20200328_164548227.jpg

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That is burning very rich, dangerously so in a closed building even if the vehicle door is open. That color yellow is NOT the calcites in the refractory, it's propane burning on ambient oxygen. 

Lean that puppy out! How close to the throat is the jet? 

Frosty The Lucky.

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The flame is still way rich but better. Nope, trim it back till it's 1/2 way back across the intake. What diameter mig contact tip is this one?

Oh, there's one important correction I need to make to an earlier post by you, REALLY important. Being able to evaluate things like flames or what a spark test means or what to draw a temper, etc. Isn't about smart, it's about experience. Some of us have been playing with and tuning these things a long time and just know what we're looking at and why it's doing THAT. 

It's not smarts, it's a little knowledge and a lot of practice. 

What is smart is asking about something you're not sure of, listening, adjusting and asking again. That my friend is SMART!

Remember only adjust one thing at a time, then test make comparisons and notes. One thing at a time or you'll never know what did THAT and you're lost. Been there done that, happily I was really young and got straightened out. Well as much as I straighten out.

Frosty The Lucky.

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Thanks frosty, it's an 035 tip. I followed the t burner instructions, I'll trim that tip back some more and report back with pics of it in the forge shell. Also, I'm wondering if I should cut the hole in the forge shell and insulation before I rigidize it or if it doesn't matter. I know I've seen it talked about before I can't find it again tho. 

 

Thanks for everyone's help, I'll be leaning heavily on advice here since this is my first gas forge. 

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  • 3 weeks later...

Frosty, I'm finally getting my wool and refractory supplies shipped in. I'd love to run my ribbon in the same NARB fashion as yours. However, I have a tendency to over size things and my inlet for my  block measures 4.25"x10.5". I'll definitely be testing with a wood block prior to casting. I'd like to leech off of your experience a bit. For that surface area would a single inlet for the plenum be sufficient naturally aspirated? Or am I probably looking at forced air or multiple inlets? I can supply concept renderings if it'll help, but I figure you won't need them.

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

I'm afraid that isn't enough information to answer your question. I'm not clear enough of what you're asking.

Frosty The Lucky.

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Sorry Frosty, finally recovered the password for my original account. I'm building out of an old air storage tank (the kind you pump up with a compressor) it's 16" Long with a 12" Diameter.

I cut both ends off so I'm left with an open cylinder. With both ends closed with soft IFB (obviously it won't operate fully closed :)) and 2" of wool, rigidized and IR coated, the volume is +/- 3200 in³. The opening I cut into the top for the ribbon burner is 4.25" wide and 10.5" long (area of about 44.5 in²), leaving 2.75" on either end. 

 

I was planning on running forced air into the plenum as that's what Wayne suggests in his build, then I ran across this post and had to stop in to look. I really like the idea of being more portable without the need of a generator or other nearby electrical source.

 

So, long story short. Before I start haphazardly welding things together.  Do you think one of the MIG tip style delivery systems you like will perform well in this situation? OR, Do I need to scale down and use a smaller shell?

 

Regards,

      Alaric Powell (AMPowell)

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I think your math is a bit off. If your cylinder is 16” long and 12” in diameter and assuming that the tank walls are 1/4” thick, that you will be putting 1/2” of hard refractory on top of the wool, and that you’ll be stacking the bricks on edge so that they take up 2-1/2” from either end, your forge interior will be 7” in diameter x 11” long.  That puts the working volume at about 350 cubic inches.

 The good news is that that’s certainly within the operating range for a 3/4” Frosty T-burner NARB, as I can personally attest (although I admit that I have not gotten it up to welding temperatures).

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Wow, don't know how I fudged that SOOO bad (EDIT: I multiplied the DIAMETER instead of the RADIUS, OOF!) , was operating on V=πr²×L (3.14 x 16 = 50.24, x 16=803.84in³) The 7x11 interior would come out to about 423in³ (add salt because my math is rusty <obviously>)

Anyway

Link to 3D concept: https://skfb.ly/6RRMJ

And Picture: the measurements below are Interior on the top box and Exterior on the cylinder body

Dimensions_Resized.jpg

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2 minutes ago, Alaric Powell said:

The 7x11 interior would come out to about 423in³

 

22 minutes ago, JHCC said:

your forge interior will be 7” in diameter x 11” long

Sorry, my mistake. That should have been “your forge interior will be 6-1/2” in diameter x 11” long” — I forgot to subtract the estimated 1/4” wall thickness. With that additional reduction in the radius, the volume drops down to my result of ~350 cubic inches. 

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Good to see you posting again Alaric. The physical size or shape (within reason) of a NARB isn't what you have to balance, it's the size and number of outlet nozzles.  19 crayons is what worked in mine. 

I have no idea how one would work with more than one T inducer feeding one plenum but I suspect they'd be fighting each other. 

Other than that you and John are hashing this out nicely, I'll just follow along in case I can add something.

Frosty The Lucky.

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