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I Forge Iron

Naturally Aspirated Ribbon Burner. Photo heavy.


Frosty

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I'm just glad there's a group of such understanding guys out there who will let me crayon their shoulders about it.

Daguy

31 minutes ago, Frosty said:

I'm wondering that too John. I hope he didn't wax pugnacious and just bulled ahead with the project.

Frosty The Lucky.

I kept working at the project doggedly.

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Well my crayon project is going mostly well.  I have some VERY positive things to report, but I'll probably be recasting.

I used a 2 X 2 stainless square tube for the Ribbon burner with dimensions per Frosty's OP.  After casting, I found that the refractory rattled a bit on the mix chamber, and leaked.  The leak could no doubt be fixed with high temp caulk available online, but I'd rather have a tight fit, so I think I'll bust off the casting, weld on some expanded metal to reach deeeper in to the casting, and recast.  Also, I made the mistake of trying to drill out the crayons after only letting it cure for 24 hours, with the result that I broke one corner off halfway up the port.  IMPORTANT WARNING:  if you're making a ribbon burner, melt out the crayons, don't drill them.  

I cast with 20 holes, 3 rows of 7, 6, 7 with the port pattern  7" X  1-3/4".  I tuned the tee burner before I had anything else made, with no back pressure of any kind (Just a thread protector in open air) and was wondering if I needed to go to school or something.  I could hardly get it to stay lit.  I got it to run as smooth as posssible that way, and when I finally threaded onto the ribbon burner, OMG!  As long as I let it run long enough to heat up the face of the RB, It ran strong from 1 to 22 PSI. Now I can build the forge and have the burner for curing the layers.  I'm pretty excited to see how it turns out.  

Kudos to Frosty for all his work on they NARB and thanks. 

Photos:

The flame photos are at 1, 10, and 22 PSI, with the orange flames from residual wax and paper burnouts.  When it's in the forge and has some back pressure, it should reach forging temps easily.

It will be mounted on a $20.00 wheeled stainless cart from a local online auction. 

I made the mold from pine, used packing tape on the interior before assembling, and then covered with Crisco as a release agent , and it came off like a dream. Definitely recommend this method. 

Using a 12" round Propane Grill sized tank as a housing, and the burner looks like it is very appropriately sized.. More as it comes together.

 

Daguy

 

 

 

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Round one of testing is complete. I ran the forge at 5psi for 2 minutes and was at 1500f (I think it was mostly just direct flame heating, the forge wasnt really hot yet). I then cranked it up to 10psi and hit 1750f at 5 minutes, 1900f at 8 minutes, 2000 at 9 minutes, and 2040 at 10 minutes. I stopped making notes at that point because it basically plateaued between 9 and 10 minutes. I didn't go up higher than 10psi because I didn't want to burn the thermocouple before I got a chance to test the Matrikote. 2040f is dang near welding temp anyway, I'm stoked that it does that at only 10psi. I also put in a 2"x1.5"x1.5" block of cold rolled to see how long it would take to come up to temp. It's a little subjective, but I'd say it was up to a nice yellow heat by 3:30. I would also note that after 20 minutes at 10psi, I turned it down to 5psi and did a little forging. It started "woofing" after about 10 minutes at 5psi. Turned it back up to 10psi and it was fine. I'm going to paint the flame face of the burner with the matrikote and see if it makes any difference there as well. 

 

I'll paint the forge interior with Matrikote tomorrow morning and then hopefully do the "after" testing on Saturday sometime. Maybe I should make a new thread with the complete results? I don't want to clutter up this thread too badly.

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Daguy: I'd read about the casting breaking free from the plenum and they were opening a side the way you did. That's why I sliced the side completely off. It makes intuitive sense that the 90* angle at the opening would grab the refractory better but it makes a weak point in concrete construction. So I played it safe and cut one whole side off so it contacted the refractory like a blade. The expanded gave it tooth at angles other than 90. 

If you guy's burners work like mine do 5 psi might not supply enough fuel air through the burner block to keep it cool enough to prevent it burning back. I believe when you turned your hot burner back down and it started woofing after a while is an expression of inadequate cooling flow.

Clutter away, you guys are making me feel pretty good. :)

Frosty The Lucky.

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I don't have the burner properly mounted yet, so there's a little hot gas leakage around it. Whenever I permanently mount it on the forge, I'll pack wool around it, that might help keep it a little cooler. Its possible that it's just something inherent to the design though. There should be a balance point where the cooling effect of the fuel/air mix can no longer counteract the heat soaking from the chamber. That balance point will change for each forge though, depending on insulation and size. Fir mine, it might be lower than 5psi, since I had it hotter and then turned it down after it was already heat soaked. If I started out at 5 and stayed there it might be ok for quite a bit longer. Maybe after I finish this round of testing I'll do another. Do a cold startup at 2psi and see how long it takes to get to temp, what that temp is, and if/when it starts woofing. Then crank it to 5 and see what happens. It's really not critical though, since I'll probably end up doing most of my forging around 10psi anyway. It just might be nice to be able to burn it lower for heat treating purposes. 

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On 7/20/2018 at 1:22 AM, Frosty said:

Daguy: I'd read about the casting breaking free from the plenum and they were opening a side the way you did. That's why I sliced the side completely off. It makes intuitive sense that the 90* angle at the opening would grab the refractory better but it makes a weak point in concrete construction. So I played it safe and cut one whole side off so it contacted the refractory like a blade. The expanded gave it tooth at angles other than 90. 

I think I'll follow your advice on the next one, Frosty. 

Quick question for the goup:  I used castable # 2 from Wayne on this burner, but due to the way I put  it together and tried to remove the crayons, I'm redoing it.  At this point, $30.00  worth of castable for each mistake is going to be cost prohibitive, so I would like to buy castable in bulk so that it is less costly per unit, making it affordable for experimentation.

I know a different castable is recommended for Forge than for Burner.  What properties should I look for for a Ribbon Burner castable?  Should I be getting something along the lines of Mizzou or or Loucast?  Recommendations for a brand for the burner?  

Thanks for the input

Daguy

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Daguy, I know nothing so hope to learn from your last question as well!

Im really enjoying you and others sharing your ideas, progress and even the failures.

My gut tells me materials with lower thermal expansion rates would be less likely to crack, and a material that is more insulative might have less issues with causing preignition at low pressure/flow rates. Finding also the right thickness to control thermal mass and therefore issues maybe when you first turn down the gas from running it hard.

All speculations from a guy (me) with zero gas forge experience, even less NARB experience, just a runaway mind that likes to design and troubleshoot things.

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I also think I mixed the refractory a little dry because I was Hyper-Nervous about putting in too much water after reading the threads and the manufacturer's instructions on pretty much ALL refractories I read up on.  So when I vibrated the mold it may not have settled well. 

I used a seven inch long 2X2 square tube for the mix chamber and didn't have enough of the refractory #2 to fill the mold, so the top 1/2 - 3/4 inch was made up by using some refractory #1, Which has more voids in it, and this was where the mix chamber met the refractory.  That's another reason I'd like to buy the ribbon burner refractory by the 55lb bag rather than by the pint.  I'd rather have too much than too little.

Daguy

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I don't know what Wayne's castable #1 & #2 are, but I used Mizzou in my burner. It's what the ribbon burner plans floating around out there recommend. Supposedly Kastolite isn't tough enough, but I think it's what Frosty used in the original NARB (strengthened somewhat). Seems to me the expanded metal on the edges is almost required in these smaller size burners. There's just not enough room for a decent lip on the cutout and 3 rows of holes. My mold was 2x2x7, and 2lbs of mizzou was pretty much exactly enough to fill it. I used the mixing instructions from Hard Luck Forge. I've fired it to full temp a half dozen times so far and it seems to be holding up well. There's one hairline crack across the face but it's only about 1/4" deep. I used an old toaster oven for the initial heating/crayon melting. Just took it to 250, 350, and 450 for an hour each (cooling between each cook) after letting it air cure for 24 hours. 

As far as buying the refractory in larger amounts, it's probably not worthwhile to get a whole 55lb bag of mizzou unless you're going to line some forges with it too. At 2lbs a pop, that's a LOT of burners. Hard Luck sells mizzou in 5, 10, and 20lb bags. A 5lber would do 2 NARBs. 

In your case, I'd say most of your issues came from mixing refractories, rather than the amount of water you added. Different castables will have different heating and expansion rates. You might get away with doing that on, say, a forge liner that's only 1/4" - 1/2" thick. A 2" thick block is gonna have problems.

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Daguy: When you say, "made up the top . . ." do you mean you added it as a layer on top of the other refractory? That's inviting a failure along the joint, mixing them together in the pot should work alright if not ideally. 

Casting concretes in layers and having bonding issues is the main reason I haven't messed with isolating the flame face of the burner block with a more insulating layer. There are methods of doing it but Kastolite is too expensive to experiment with on that level so I just think about it. <sigh>

The water content in the company mixing guides is for maximum strength, we don't have to worry about banging rail cars into out liners so we can get away with more workable moisture content. Don't mix it wet though, it should barely slump and if there's free moisture on it add more refractory and stiffen it up. Kastolite contains crushed aggregates so it's just not possible to work it as dry as recommended. Heck, even close to recommended water content. I believe the mixing guide is for gunnite application rather than trowel.

Yeah, I think a pint isn't enough but a 55 lb sack will last you through a couple few forges with spare burners . Don't get carried away because of a couple failures, this was more a mistake in working concrete than a material failure. It's just a learning curve thing don't let it get to you.

2nd: The lip is the problem bonding concrete to steel, it's a built in cold shut, literally. I don't think the kind of refractory you use makes a lot of difference so long as it's performance meets specs, 3,000f. max sustained temp rating hits about as hot as it's possible to make an air propane flame, I believe 3,200f+/-. is the actual number. I made mine from Kastolite 30, there's one crack in the first NARB but it showed up during cure about 2 days after casting. A mistake in concrete management during the casting process I'm pretty sure.

Don't melt out the crayons until AFTER the refractory is fully cured, same for heat curing. Kastolite wants to cure almost exactly like Portland cement concrete so those are the procedures I followed to good effect though I didn't give it a full 7 days at 100% humidity after it fully set, I gave it more like 48 hours sealed in a plastic garbage bag with a couple cups of water.

Greasing up the crayons allowed some to slide out when I opened the mold and I was able to pull a couple more out with pliers. Some guys have good luck using a drill bit as a hand tool. I've given thought to grinding a bit down to fit my pin vise, maybe if I make enough to need to worry about production methods. Plastic rods might be an option worth looking into as well. Crayons aren't strong enough to pull on very hard you know. As I recall they're pretty good for chewing though and they don't leave your mouth a weird color so your Mom won't know. :)

Frosty The Lucky.

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23 hours ago, Frosty said:

Daguy: When you say, "made up the top . . ." do you mean you added it as a layer on top of the other refractory? That's inviting a failure along the joint, mixing them together in the pot should work alright if not ideally. 

Yeah, that's exactly what I did.  I realized at the time it was a dicey move, but I just didn't have enough of the other castable to fill the mold, and I'd already used up what I had.  I tried to poke the second material into the first to avoid a straight layering of different properties, but I suspect more disaster awaits this ribbon.  SOLUTION:  I have 20 lbs of Mizzou on it's way, and I'm building a new mix chamber  with straight sides and expanded metalas per your original post, though I only have a smaller mesh  expanded available in the scrap pile at work, but that should just provide more material and angles for the castable to grip. 

Thanks for the heads up on when to remove the crayons (or I might use small glue sticks if they're close to the same diameter).  I'm a metal working guy, not into concrete, so it's a total Newb huge learning curve for the NARB.  I'm actually totally geeked at how well the first one turned out.  I decided to just make a new one from scratch and maybe keep this one as a wall hanger to remind me from whence I started.  I'll also read a lot on the proper pouring and curing procedures for Mizzou

 

Thanks for the input and I'll keep updating the thread with my progress.

 

Daguy

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I tried measuring how much castable to use before mixing by filling the mold with dry mix but it came up a little short so I mix more than I THINK I'll need by maybe 1/2 cup. The volume of Kastolite actually decreased with the added water rather than increasing like a Portland cement concrete mix design. It still cures like Portland cement for maximum strength and requires no flame cure cycles, funny stuff. I still like to bring it to forge temps in a couple cycles but that may be an artifact of my preference rather than  necessary. 

The finer the expanded the better within reason, I'm lamenting how little of the small mesh I have left. If I run out I'll be splitting the larger through the centers of the expanded sections. That works just fine one of my previous NARBS is done that way, I couldn't locate the preferred expanded sheet so I went with what I could find.

It's the shape and angles of "penetration"(?) that matter, not a specific material. Welding short lengths of welding or brazing rod to the edge at angles should do the trick nicely. Welding them to the inside of the plenum might work better but I'm not sure if the refractory extends beyond the outside margin of the plenum. 

Make sense?

Frosty The Lucky.

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  • 2 weeks later...
On 7/23/2018 at 3:01 PM, Frosty said:

The volume of Kastolite actually decreased with the added water rather than increasing like a Portland cement concrete mix design. It still cures like Portland cement for maximum strength and requires no flame cure cycles

Would you expect the same to hold true for Mizzou?  It arrived this week and I have the next couple of days off, so if the missus doesn't have too many chores lined up, I may get around to casting the replacement soon.

 

Daguy

On 7/23/2018 at 3:01 PM, Frosty said:

It's the shape and angles of "penetration"(?) that matter, not a specific material. Welding short lengths of welding or brazing rod to the edge at angles should do the trick nicely. Welding them to the inside of the plenum might work better but I'm not sure if the refractory extends beyond the outside margin of the plenum. 

I actually went with an 1/8" woven stainless.  after welding all the cross sections in place, I cut it and welded it in line with the plenum walls.  I built my form so the finished burner would be about 1/4"  larger all around than the plenum.

Daguy

Plenum.jpg

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I've never used Mizzou I can't say anything about it other than it's been in use a lot longer than I've messed with propane forges so it's gotta be a good refractory. 

That's a lot more reinforcing than I put on my plenums but it should work nicely.  That wouldn't be called 1/8" woven. It's more like a 1 mesh screen. That stands for openings per inch and the wire dia doesn't count. 1 mesh is one opening per inch, NOT 1" openings.  

Jer

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Wow, this is really good information!  New here, first time posting and looking for ideas/knowledge for this style of burner.  Frosty - have you experimented with (or seen) using the "ports" in an angled fashion?  I'm wondering if the middle row vertical and the outside rows at a slight outward angle would be beneficial in any way?  Thought maybe a better "swirl" or something similar in the forge?  I don't know, just thought..."hmmm, wonder if someone has tried that before?"  

I'm going to start my first ribbon build soon so I appreciate all the effort and time this took (and continues to take) from all on here!

Wes

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Welcome aboard Wes, glad to have you. If you'll put your general location in the header you might be surprised how many of the gang live within visiting distance.  Seriously, new folk have turned out to live within about 15 -20 miles of ME!

Yes, I've thought about different angles and what effects they may have in a forge chamber I just haven't messed with any yet. Casting refractory burner blocks is a lot of work for experiments. That's the reason I experimented with 2" x 4"s drilled the outlets.

They don't last long, a minute and they're on fire and is longer than I needed to see if the pattern and number was functional. A few seconds is plenty to tell me what I needed to know.

I tack welded a piece of angle iron about 1/4" back from the plenum's edge on the long sides and screwed it down till the angle was against the wooden test block. That's enough seal for testing.

If you want to experiment with either a NA or gun type multi outlet burner I highly recommend you use something quick to make and you don't mind replacing after a brief test. I did test burns in a brick pile "forge" with no intention of bringing to forging temps. They burned just long enough to check performance against back pressure and jet psi range. 

We know both types work, there isn't anything new about either, they've been around for centuries look under your range top or in a heat treat furnace or kiln. New construction methods for cast or whatever burner blocks isn't nearly as interesting as a new flame form in a furnace. The NARB really is just a bare bones thing, hardly interesting in itself other than how easy it was to make and how stable it is.

Keep us in the loop if you get into testing. PICTURES! please. ;) An interesting flame shape is always worth looking into.

Frosty The Lucky.

 

 

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  • 2 weeks later...

So the Narb is complete and burning like a champ.  I cut the burner port in the shell and just have to figure out how I want to attach it to the shell at the angle I want and Ill be ready to insulate, cast a lining , and start bragging.  Pics as I proceed.

Lots going on so the build has to be fit in around the edges, but I'm having a lot of fun  and learning a lot..

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