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I Forge Iron

Naturally Aspirated Ribbon Burner. Photo heavy.


Frosty

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This looks really cool Dan!
I'm keen to see how well it works at max-heat.  If it will comfortably reach welding heat, then I may modify my NARB setup as well.

I've just done some hunting, and using Ceramic Honeycomb search keywords, managed to find the same ceramic elements as you on Amazon.uk for around £12, so cheap enough to play with.

Good to see you posting again.

All the best matey,

Tink!

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Failure... I got excited and posted too soon :(.

The honeycomb melted at high temps... BUT... before it did, I got 130F extra out of it at 5 lbs compared to my NARB - same burner, same forge, etc.  My NARB gets to 2170 at 5 lbs, the honeycomb was sitting at 2300.  So lots of tiny holes work very efficiently.  

Analysis: First I preheated at 5 lbs for 20 minutes or so, everything looked fine.  I turned it up to 12lbs, heating up a canister for welding.  Failure happened only about 5 minutes in, the canister was just turning red.  The a thin line along the edges of the honeycomb, where it was against the mortar, was a lot hotter than the surface - glowing brightly.  The surface is not flat.  It's got dimples with 6 holes in a hexagon around the edge and a center hole in the bottom of each dimple.  It seemed to melt in the center of each hole.  The burner was still working fine when I turned it off.  The inside surface was obviously being kept cool by the moving gasses.

The other thing about this honeycomb, is I'm not sure it was a cordierite ceramic.  This one was not labeled as such but the company offered one other plate that was smaller that was labeled as cordierite - I got this because it was larger.  I noticed that two kinds are sold, one commonly for soldering boards that is rated at 2000F, and the cordierite ceramic that's rated at 1300C (or 2350).  It's sintered at 1400C (around 2550), so it should take quite a high temperature.  

Back to the drawing board... :P  The fact that this worked so well (before it destructed) gives me some other ideas.  I thought of drilling 1/16 holes in high density ceramic fiber board.  There's some on amazon, .8" thick and 2750F max temp.  That should be enough, and I know the back won't get too hot.

Hey Tink!  Hope all is going well!  Don't buy any yet...looks like I have more experimenting to do.  

 

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It looks like it melted in the areas with lower gas flow. Would that mean that the size was just too large for the output? Not sure how it the flame would perform with half the size, but maybe the ceramic would hold up.

Any thoughts?

David

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42 minutes ago, Goods said:

It looks like it melted in the areas with lower gas flow.

Good point, but I'm not sure.  The flames looked pretty even throughout.... but there is definitely a relation to the gas flow and the melted part.  If you look carefully at a zoomed pic, every center hole on the bottom of each dimple is starting to melt. It might be that on the edges the gas is flowing at an angle or more turbulence or something.  

I'm not willing to continue down the line with this material, it failed too quickly and I'm afraid it could fail catastrophically.  It does confirm for me that the small hole concept is a winner, and I'm going to try some other approaches.

Dan

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I went ahead and bought a codierite one for $10. It looks a different color than this, so I might have gotten a 2000f one, not a high temp one. Hopefully I can remove the burnt up one and put this in its place. I hope it works!

 

Dan

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Good to hear from you Dan. Hope all is well with you.

Re. The honeycomb.  That's a real shame, but you've got some pre-failure info which is good.

I remember these sorts of honeycomb on portable gas heaters, where it seemed that the front face would glow orange and appeared to radiate as much as the flame (you could turn off the flame and feel how much heat was still coming off the honeycomb). I agree that if we could find high-temp honeycomb it would be the "Holy Grail" of NARB development! :) I'll keep watching your experiments with keen interest.

On another note, I've been getting a few people in the UK trying out your Zircopax/Silica (ZS) slurry for flame-coating of rigidised Ceramic blanket or board. They have reported very positive results, so we have a few more converts to the ZS slurry approach. :D

All the best,

Tink!

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Thanks Tink!  Haven’t been pushing the ZS just cause finding the right colloidal in small quantities is nearly impossible here. The one person who was selling it doesn’t anymore. 
 

1 hour ago, Another FrankenBurner said:

Hopefully better luck with the codierite.

Already got the cordierite, it looks the same but we’ll see. BUT, I have another plan...it just requires drilling 500 holes LOL. But that’s what a CNC mill is for. I’ll spill more if it works. 
 

Dan

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It's Funny Dan,

It's pretty easy to get Colloidal Silica in the UK, but a pain to have to import Kastolite30 from the States, yet you have the problem the other way round!  Ho-Hum!  It's a weird world we live in, and people just have to find out what works for them.

Re. a CNC mill.  This has been on my Tinks-Toys list for so long now!  Very jealous! :D

Tink!

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Dan: Have you checked with a fiberglass supply? Colloidal silica is commonly used as a thickener in resin, polyester or epoxy. I could buy it in 55gl drums locally and I live in Alaska. I grew up in the San Fernando Valley, worked in Burbank and we thickened resin for some of the parts we made on a regular basis. There was a big cardboard barrel in the supply room. I didn't know what it was at the time but it was almost certainly silica. We had to wear a mask and turn on the exhaust fan before opening the barrel.

I think you must be looking in the wrong place. You can get ANYTHINNG in L.A.

Frosty The Lucky.

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  • 4 weeks later...
On 3/12/2021 at 8:52 AM, Frosty said:

Colloidal silica is commonly used as a thickener in resin, polyester or epoxy.

Sorry to disappear for a bit.  

It's easy to get that kind of colloidal silica, but it's not the same as the colloidal I'm using.  I tested that kind, and it makes the ceramic fiber melt.  What I'm using is a colloidal silica binder for ceramic shell casting.  Look up "Remet colloidal silica" (Remet is a company that makes it).  They don't have what I used to buy, Adbond II, but I think their Remasol is the same type of thing.  I used to buy it in 5 gallon containers.  Don't really see it sold in smaller lots.  It's a completely different animal than the fused colloidal silica we use to rigidize wool - at least in how it works.

I've moved the experiment to using ceramic fiber board that I found on Amazon:  "BXI Ceramic Fiber Thermal Insulation Board (2732F) - Inorganic - Flame Retardant, Heat Resistant (12'' X 8'' X 0.8'')". My first couple of test blocks worked well. It holds up to the heat just fine - I'm going over my pyrometer which tops out at 2400F.  I'm finding that rigidizing it with the colloidal/zircon mix first is working better for drilling, if I don't it rips out since the holes are so close.  I'm playing with different amounts of holes.  My last try used less holes and I got the dreaded organ harmonics that didn't want to go away.  I'm playing with it as I have time, which is less than I'd like.  I'll keep you all up to date as I get any successes.  

The unfortunate part is that while I can drill 500 holes with my CNC, not many people have that (it's still a 45 minute program run).  We'll have to see if it is a working proposition for others to use.  

DanR

On 3/9/2021 at 7:49 PM, Another FrankenBurner said:

Well that is a bummer.  Hopefully better luck with the codierite

Same problem.  I think the first was cordierite as well.  Playing with fiberboard... see post above.

On 3/11/2021 at 1:41 AM, tinkertim said:

It's pretty easy to get Colloidal Silica in the UK, but a pain to have to import Kastolite30 from the States, yet you have the problem the other way round!  Ho-Hum!  It's a weird world we live in, and people just have to find out what works for them.

Easy to get... just not in small quantities.  I used to buy it in 5 gal batches which is the smallest they normally sell.  I stopped doing shell casting, but have a couple of gallons left over from literally a decade or so ago.  

The CNC is fun!  If you were out here, I'd be happy to share :) 

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On 3/12/2021 at 11:52 AM, Frosty said:

Dan: Have you checked with a fiberglass supply? Colloidal silica is commonly used as a thickener in resin, polyester or epoxy. I could buy it in 55gl drums locally and I live in Alaska

Restaurant suppliers too. It's used to thicken food products and as an additive. 

Pnut

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  • 4 months later...

So I was reading through this thread, and had seen some of the discussion on tapered exit ports and tapered holes. As I was reading it I wondered if anyone had thought of using golf Tee's as the cores for the burner holes?

IIRC they are about 1/8 or 3/16” in diameter along the shaft and flare out near the head to something around 3/8 or 7/16” at the top. Seems to me you could cut them off at whatever exit size you wanted and end up with cast in micro retention nozzles. They come in both wood and plastic types, and with the wood painted they should be easier to grease up to release from the castable used.

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I haven't but I don't think much of tapered outlets as flame retention nozzles. My first reason is, A properly balanced flow prevents the flame from jumping off the nozzlettes and provides cooling to prevent the block overheating to the point the fuel air mix reaches ignition temp in the block and burns back into the plenum.

Reason 2, The expanded shape facing into the forge is subjected to increased IR radiation without the cooling provided by the flow in contact. 

With the wide part of a T facing inward there would be increased contact with fuel air flow for increased cooling. However the outlet narrowing towards the forge increases the flow velocity making it necessary to reduce flow to prevent the flame from jumping off the block.

If you give it a try, please keep us in the loop. I've been wrong so many times I should have a pHD or two, learning from my mistakes. 

Frosty The Lucky. 

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