Jump to content
I Forge Iron

Naturally Aspirated Ribbon Burner. Photo heavy.


Frosty

Recommended Posts

  • Replies 1k
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

Man this has been a busy thread! I'm just going to take things as I do. Adapt eh? :)

Mosul: Buddy, you really need to do some proper research and Youtube is a really BAD place to count on. 

First thing you need to decide is what kind of furnace you need. If you wish to melt metal then the specific type of furnace you need is a "melter." What kind of metal determines how much heat is needed. The video you linked shows a seriously over worked on melter built by someone who doesn't really know what he's doing. Plastering the inside of IFB (Insulating Fire Brick) with refractory mortar is a near complete waste of time and money. Refractory MORTAR is formulated to stick things together not act as a flame face where it WILL degrade rapidly.

What brings you to think ribbon burners are appropriate for a melter? If it were your arrangement would be especially poor choice. I'm not just being picky, you did after all ask and that's a good choice. ;)

A melter NEEDS a strong fast flame, usually a single, single outlet burner though for large melts a burner belt may be appropriate. As Dan said, the flame needs to be introduced tangentially to the melter wall at the bottom where it maintains contact with the crucible for the longest time possible. 

That brings us back to the Youtube video. The person posting a how to build a melter didn't put his crucible on a plinth. A plinth is a refractory block the crucible rests on so flame can circulate under it for MAX heat transference. Yes?

Hit the library for REAL books, while a powerful tool the internet isn't so great if you don't already  know enough about a subject to sift the wheat from the chaff. Some of the junk posted as how to articles and videos are down right DANGEROUS. 

I'm hoping one of our resident bibliophiles posts some good titles for you. I'm not a caster though I have taken part in pours and did quite a bit in jr. and senior high school. I know enough to know how ignorant I am

We aren't trying to discourage you from learning a new skill, we like to see folks succeed and post cool pics of what they do. We just don't want to see someone waste a bunch of time and money on bad plans, worse than that we really don't want to read an obit or hear about someone in the hospital after being splashed in molten metal. That's B A D on toast!:o

Frosty The Lucky.

Link to comment
Share on other sites

1 hour ago, jlpservicesinc said:

That is really cool.. .

We have 2 major gas organs and 3 smaller gas organs right here in the house.. :) 

You have a lot of gas then Jennifer? :rolleyes:

Dan: thinking about it I have to wonder if the FAM isn't blowing across outlets like blowing across a bottle making a note.

I love the link John, thanks. 

I have an online friend who has built beach organs that sing in the wind. 

Frosty The Lucky.

Link to comment
Share on other sites

7 hours ago, Frosty said:

Dan: thinking about it I have to wonder if the FAM isn't blowing across outlets like blowing across a bottle making a note.

Possibly.  The inside is probably really rough. The mizzou was too course to pour between the wax sprue rods - a real pain, I had to push bits down with a knife blade.  Also, I'm getting a similar sound (though much less and more intermittent) on my other burner, and that has a baffle above the outlet holes.  On the forced air I have to get the right mix (neutral to slightly oxidizing) to make it sing, don't know about the NARB yet til I get home.  I think your first guess was closer, a little blowback forming a resonance.

JHCC - thanks for that post!  What a wild invention....somehow glass tubes and explosions seem a bad combination....

MOSUL - Frosty is right on.  Don't get discouraged!  Let us know first what you want to do and I'm sure we can direct you.  As an optical engineer, please understand this is not rocket science, building a furnace is a simple thing - don't overthink.  We'd love to help, the place to start is looking at the end point - what you want to do.

TINK - Thanks!  It does make a beautiful sound!  Loud enough for any orchestra.  I like the idea adding anvil percussion!

7 hours ago, Frosty said:

Dan: thinking about it I have to wonder if the FAM isn't blowing across outlets like blowing across a bottle making a note.

Possibly.  The inside is probably really rough. The mizzou was too course to pour between the wax sprue rods - a real pain, I had to push bits down with a knife blade.  Also, I'm getting a similar sound (though much less and more intermittent) on my other burner, and that has a baffle above the outlet holes.  On the forced air I have to get the right mix (neutral to slightly oxidizing) to make it sing, don't know about the NARB yet til I get home.  I think your first guess was closer, a little blowback forming a resonance.

JHCC - thanks for that post!  What a wild invention....somehow glass tubes and explosions seem a bad combination....

MOSUL - Frosty is right on.  Don't get discouraged!  Let us know first what you want to do and I'm sure we can direct you.  As an optical engineer, please understand this is not rocket science, building a furnace is a simple thing - don't overthink.  We'd love to help, the place to start is looking at the end point - what you want to do.

TINK - Thanks!  It does make a beautiful sound!  Loud enough for any orchestra.  I like the idea adding anvil percussion!

Link to comment
Share on other sites

Well I'm home from my trip, had an hour to play with the new burner!  

The sound:

I found when I change the mix to reducing the whistle goes away.  As the mix moves towards neutral the whistle comes back.  I can make it get louder and softer by putting my hand over the intake on the Venturi (I'm using a standard Reil Bourdeaux modification). When I do this I can actually see the flames vibrating and then stop vibrating when I put my hand on the intake.  After about 2 minutes the burner head heats up enough and the whistling dies down and goes away - takes about 10 seconds.

The heat:

Once warmed up I turned it down below what the gauge could read and the flame was stable.  I then continued to turn it down so low it wasn't pulling any air and turned into straight propane flames - no backfire at all.  But the burner head wasn't really hot yet, so we'll have to see once it's been running a bit longer.  

I then turned it up to 7.5 lbs and the forge stabilized at 2130-50 F.  Before I modified this forge for the ribbon burner I used to forge at 5-7.5 lbs with this same Reil burner (haven't changed insulation or anything).  It has a more even and wider heat area than with the single burner and 1" nozzle.

I then turned it up to 10 lbs and the temp increase was slowing down at 2220, but then....

...I ran out of gas. :unsure:  This may have also effected the 7.5 lb test, so I'll do it again once I fill my tanks.

Next: I'll run it at 10 lbs, 12.5 and 15 lbs (12-15 was my welding temp with the single burner), and let it run for an hour til the burner is hot (probably weld up a billet).  Then I'll see what kind of stability it has at low pressures of 1/2-1 lbs. and see if it will be stable at tempering temperatures.  It's looking like it might be...but we'll see!

Dan R

Link to comment
Share on other sites

Since the burner is working so well, I thought I'd post some pics of the build.  I used an ancient box of Kerr sprue wax, the rods measured 1/8" x 4" long.  Can't find that brand anymore, the closest I see on amazon is 8 gauge which is 3.25mm or .128".  I cut the 4" rods in half.  123 holes = 64 pieces cut in half.  It came to 1.55 oz of wax.  The wax on amazon is $25 for 8 oz.  That's enough for 5 burners the size mine was, so purchased new it comes to about $5 of wax for the one burner. 

The main problem I had was that the aggregate in the Mizzou was too large to fit between the sprues.  I had to use a thin knife blade to push the refractory between the rods in little bits.  Took quite awhile and the Mizzou started to set up around the edges...then I had to dig up a groove to put the Plenum into...basically it was a bit of a cluster ****.  But I got it together (no pics of that part of the build). I believe that Frosty has mentioned running the refractory through a strainer to remove the aggregate.  I'll try that if I do this again (and I might for my longer forced air ribbon burner).

I made a plate with matched holes thinking the wax would bend, but the 2" pieces kept pretty straight and I didn't use it.

IMG_7216.JPG

IMG_7221.JPG

IMG_7222.JPG

IMG_7223.JPG

IMG_7224.JPG

Link to comment
Share on other sites

That's really close spacing Dan, I had trouble getting Kastolite between the crayons and they're a lot farther apart.

I wonder how it'd work to replace the aggregate with zircopax. 

Your method looks just like mine without paint.

Frosty The Lucky.

Link to comment
Share on other sites

It was a pain, and it took a bit of time, but it ended up with a good solid face.  I did a lot of vibrating to try to get the bubbles out and it worked.  One thing I'm noticing is that the area with the nozzles is staying pretty cool, but I ran out of gas and haven't run it very long.  I'm hoping this might be a cure for the low pressure backfire issues of multi-burners.

Zircopax is a powder (or my zircon is) and I don't think it will perform the same function as an aggregate, though it might work as a filler. On the other hand, it seems the muddy liquid that bleeds out of the refractory when vibrated still sets up hard so I'm going to try just sifting the Mizzou through a screen and see if that works.  If it does, I can try adding zircon to see if it extends it.  I might also try a paste of zircon and colloidal silica binder.  We'll see if I have the time to really play with this.

I also saw a post here of a person using a mix of 95% calcined alumina and bentonite to make a burner nozzle. He seemed to just fire in a forge after baking it at 400 till dry.  I'm trying to figure out what those white ceramic burner heads are made of - I think that would work well.  The spacing of the burner tubes could even be closer. This is the only thing I've found online. 

Dan R

Link to comment
Share on other sites

I found the aggregate was too course to get it to flow under vibration. The milky water pumping out while vibrating indicates too wet a mix and water is displacing refractory. Don't worry though, this isn't a road grade so mechanical strength isn't an issue, we're not using it to carry weight. It's an indication though and we don't want to flush the calcite binders out. 

I was thinking of shifting the gradation to more of a grout than a concrete by replacing aggregate with zircopax. Now you mention it I have zircopax flour which by definition passes a  -200 seive. The field test is to touch a bit on your tongue and se if you can feel it against the roof of your mouth or gums. NO I'm not suggesting anybody to that I'm only mentioning an old test when you didn't have the lab tools.

One of our guys here made a darned impressive zircopax and Bentone (in the bentonite family) refractory tiles experimenting with kiln washes and forge liners. IIRC he had excellent luck with 97% Zircopax to 3% Bentone. 

About not burning back. Isn't there an opening size under which a flame can't propagate? 

Frosty The Lucky.

Link to comment
Share on other sites

For what I've been making it's a velocity issue. I just had a flash of memory about a gas flame not being able to propagate through an opening smaller than . . . X

I was posing it as a question here, I remember the factoid but not where I heard it. I remember it from a lecture, or class, visit from a fire man, or?? It was either late elementary or jr. high school. Maybe I'll remember where I heard it and what IT was tomorrow.

Frosty The Lucky.

Link to comment
Share on other sites

On 3/16/2019 at 4:29 PM, Frosty said:

The milky water pumping out while vibrating indicates too wet a mix and water is displacing refractory.

I added too much water purposely to try to get it to flow better.  As you said, I wasn't worried about structural issues.  

 

On 3/16/2019 at 4:29 PM, Frosty said:

One of our guys here made a darned impressive zircopax and Bentone

I have some Kaolin clay, and some bentonite and a bag of zircopax....hmmmmm.  I'll try some mixes.  

 

On 3/16/2019 at 4:29 PM, Frosty said:

About not burning back. Isn't there an opening size under which a flame can't propagate? 

I did a bit of a internet search and found this in the eBook: Modeling of Combustion Systems: A Practical Approach. It is talking about Hydrogen rather then propane, but I bet the principle is the same. 

 "One important consideration is the 'quench distance' - a characteristic length for a given orifice geometry through which a flame cannot propagate.  For small-diameter orifices, the edges will abstract sufficient heat from a propagating flame to extinguish it.  The quench distance varies with the orifice diameter - small orifices are more effective than larger ones."

Theres an appendix that shows orifice size...but I'd have to pay $45 to see it.

This also makes me think that that may be the answer to my Singing Forge sound!  The flame is backfiring into the orifice, but looses heat and extinguishes, then starts burning back again setting up a vibration. Once the edges of the orifices heat up to ignition temps, the flame catches and doesn't burn back.

Flashback.png

Flashback2.png

Link to comment
Share on other sites

I pointed out the free moisture and reason for folk who might need the info. If you have free moisture compacting soil or heavens forbid working concrete you have ISSUES. My burner blocks shed considerable free moisture so I used the Kaowool I was using in the forge to soak it up. Waste not . . .;)

I was going to point out kaolin doesn't vitrify in a forge and needs a proper firing sequence. but you probably know that. ITC 100 is roughly 70% zirconium silicate to 30% kaolin and is an unsuitable kiln wash in a forge. Forges aren't what it's designed for.

Quench distance? Ooh, something to read about tonight! :) This isn't what I recall from the "mining museum tour." Yes I remembered where I heard it I asked how they could be concerned with methane in a mine and use carbide lamps. We got the explanation but I was too young to recall details. Seems the trick was getting combustion air in the lamp. I love it :wub:when memories trigger! Specific dia and length for quench distances isn't on my radar so unless your CAT demands it, don't spend the $45. If I get THAT curious I'll see if I can get the library ILL a copy. 

It sure sounds like a plausible cause for the singing burner. 

This is getting cooler all the time. Man I LOVE this stuff. Probably never have a use but you never know.

grumble 

 

Link to comment
Share on other sites

That's where the screen that was tickling my memory came from!

Radiant gas heaters and mantels in gas lanterns operate by the same rules. The flame can't ignite the gas behind the screen or mantel so it burns on the surface where it meets ambient oxygen. Or so the memory trigger recalls. 

Frosty The Lucky.

Link to comment
Share on other sites

Check it out---I have one!  Bought cheap at the Fleamarket in Las Cruces NM; I learned about them in Geology classes, and saw one demonstrated in Wales at a coal mine and so cheerfully forked over the moolah when  I saw one for sale at an extremely good price.

Link to comment
Share on other sites

2 hours ago, jwmelvin said:

This paper describes some investigation of the quench diameter for propane-air mixtures. Seems like 2.5-3mm is about the lower limit. 

Welcome aboard, 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.

Thanks for the link. I can see what they're doing, understand some of the test methods and devices but can't do the math. Heck, don't know what the symbols are. I know I could look them up but. . . :huh:

This has to be the coolest bunch of people on the planet and just goes to show, noting's too nerdy for blacksmiths.

Frosty The Lucky.

Link to comment
Share on other sites

Update on my 1/8" 123 hole NARB.  I welded a billet of Damascus with it today, basically same pressure as I would use my Reil burner for welding, but I could get 9" of steel up to heat without moving it rather then 5".  Once the forge was hot, (after about 1.5 hours welding and drawing the billet) I tested temperatures at different pressures.  It went from 2400F at 12.5 lbs down to 1560 at so low a pressure that the burner didn't pull enough oxygen and the flame went to yellow reducing flames, I'd guess 1/4 lb or so.  At the pressure just before the flames went yellow/reducing (maybe 1/2 lb), I was at 1630 F and the flame cones where about 1/8 or less long.   No backfiring except when I turned it off.   None.   Perfect performance :lol:  

I got a bit of yellow dragons breath out of the forge at high pressures, but it did produce a small amount of scale on the metal in the forge. Must still be reducing, cause I welded the billet without flux at about 2350 F with the damper on the burner wide open (full air). 13 layers, 15n20 and 1095.  Pic below.

The organ tone is loud at startup, but if I make gate off the burner intake and make it a bit reducing it goes away.  Based on the quench distance theory, and the other article listed, a reducing flame is more prone to quenching, so that supports the theory that these burner holes are at just over that edge.  That also supports the fact that they do not backfire easily.  

IMG_7259.jpg

Link to comment
Share on other sites

Well I've been hunting for a suitable container to build a new forge within, to suit my IFB-based NARB. Having seen commercial oval forges for sale, as well as reading about people using an exhaust "muffler" (or silencer in the UK), I had an idea.

You can get oval steel mop buckets from a company called Screwfix (Google: screwfix steel mop bucket) as well as lots of other places on the web.  They offer dimensions for these buckets, but it's not clear where the measurements are taken from, but from my initial guestimations it should come under my 350 cubic inch target, so I went and bought one.

Bucket_for_Forge1.jpg.7965acf1f545e0dae3c7c5f7c7c630e8.jpg

Bucket_for_Forge2.jpg.3aac94ef927769d3b8df56c2d96e228a.jpg

I then measured it accurately and mocked up a CAD layout for a two-layer of 1" ceramic fibre, with an Insulated Fire Brick (IFB) as the base, and cut a hole in it where I think the NARB would suit.

Bucket_Forge4_Anno1.jpg.c5879c4d33ea7480c13d812a292728e4.jpg

Bucket_Forge4_2.jpg.1734074320f8fc2944827bbb3602277a.jpg

The depth of the bucket is 8.5", and with the dimensions I calculated, the inner volume to be ~324 cubic inches! Right where I wanted to be with a 3/4" AMAL Propane injector feeding the NARB.

I'm hoping with the longer roof (due to the oval shape) that there should be a good amount of roof and wall to radiate IR downwards, and the oval shape should allow for swirl as well.  I will be making up support brackets at the front and back to allow for IFBs to be positioned to reduce the opening size, and I will be grinding off the galvanised finish on the edges of the bucket where flames might reach, and will coating the inner, and outer edges with the Colloidal Silica slurry and Zircopax mix in D.Rotblatt's fashion.

Any feedback on the orientation of the NARB burner?

Tink!

Link to comment
Share on other sites

It's a good shape but have you considered how much trouble it'll be to strip the galvanizing? That's a lot of vinegar. It won't get hot enough to matter on the inside but where the dragon's breath hits the outside it sure might. You don't want to breath zinc oxide smoke, it's BAD for you.

Frosty The Lucky.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...