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Post by foxtatic on Oct 15, 2020 4:40:32 GMT -8
Hello all. I'm building a DSR2 core from Ceramic Fiber Board. I had all my pieces cut but decided to do some testing on the scraps before assembly. I made a video of the results: www.youtube.com/watch?v=lwmUGAVHQtk&feature=youtu.beThe top sample is "raw". Middle sample I hit with a propane yard torch which may have been 3000 degrees F but I didn't blast it too hard. Three bottom samples were just stuck in a concrete block J tube like a riser liner. No idea what temp those ones saw but the flames seemed to have a negative effect. Rated for 2300 F, Density 19 lbs/ft^3. If you don't mind watching my short 40 second video, I'd love to hear about your thoughts/experiences to answer the question: Is this typical material? I'm hesitant to continue with the build. |
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Post by Vortex on Oct 15, 2020 4:56:43 GMT -8
The Ceramic Fiber Board I got from the U.K. was like your fired stuff from new, it couldn't take any rough handling or abrasion, but in the stove it's been subjected to 2 seasons of up to 1000C and is still the same as when I put it in, hasn't degraded from heat or gas flow at all.
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Post by foxtatic on Oct 15, 2020 6:04:40 GMT -8
Thanks Vortex, or I guess Travis is what people in the know call you  I don't think this stuff will work in my firebox at all. You've reassured me that I can still use it in the riser stub and top box. I still hesitate with my port wall since there's a ton of gas and flame pouring through this constriction and I can just imagine it weakening and stripping my fiber out with the exhaust. I do have some sodium silicate I could paint on around the port just to make sure those fiber stay bound up. |
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Post by Deleted on Oct 15, 2020 7:06:39 GMT -8
Adhesive increase the hardness and thus wear resistance of CFB. According to technical requirement, a small amount of organic or non-organic adhesive. In a temperature between 285℃ and 450℃, organic adhesive burns out when put into heating for the first time. The fibers themselves are not affected. Wear resistance at high temperatures requires non-organic adhesive.
Soaking the board with an non-organic stiffener or waterglass will improve the high temperature wear resistance of CFB made with organic adhesive.
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Post by Orange on Oct 17, 2020 0:17:20 GMT -8
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Post by Deleted on Oct 17, 2020 5:37:13 GMT -8
How about just painting it with clay or lineing them with thin clay/sand mix? Will work only for parts getting hot enough to turn the clay into ceramic. |
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Post by wrekinwanderer on Nov 16, 2020 15:49:23 GMT -8
How about just painting it with clay or lineing them with thin clay/sand mix? Will work only for parts getting hot enough to turn the clay into ceramic. So is waterglass okay then Karl? Could it be used to protect concrete which could be compromised by high temps in a bench bell? Mike |
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Post by Orange on Nov 16, 2020 23:50:43 GMT -8
I'll try it. Was also tinking of coating secondary air steel pipe with waterglass or mud to prevent degradation.
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Post by Deleted on Nov 17, 2020 2:45:38 GMT -8
So is waterglass okay then Karl? Could it be used to protect concrete which could be compromised by high temps in a bench bell? Mike Portland cement can be relatively easy made fire resistant up to about 900°C. White portland will work better than the standard gray. Even better would be sulphate free portland.
One needs at least about 20% pozzolanic material with high alumina content like grog or clay, to bind the calcium oxide (CaO) formed by heat degration of the portland. Some phosphate salts ( sodium or potassium phosphates ) may improve the heat properties.
Somewhere I gave some recipes.
Some scientific papers. The Investigation of Properties of Insulating Refractory Concrete with Portland Cement Binder
Ways to improve physical and thermal performance of refractory lining materials
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Post by wrekinwanderer on Nov 17, 2020 13:59:58 GMT -8
That's brilliant, thanks karl. And thanks for the links too! Love that. Exercises a different part of the brain...
I've been using a vermiculite concrete mix to insulate the back of our bench from the stone wall behind, and the interior of the bench to reduce the isa.
So, if I've taken it in correctly, I add 20% of our garden clay, or some ground up kitty litter green clay perhaps, to the concrete it'll become refractory to 1200-1400 degrees c? Belt and braces, coat it with waterglass too!
Karl, would this be accurate?
Orange, keen to hear how you get on with your test...
Personally, if I can get my hands on some waterglass toute suite, then I'll be painting the inside of my concrete kerb bench with it.... I'm concerned a clay slip may flake off easier or perhaps not get hot enough at bench temps to turn to ceramic... Mike
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Post by Deleted on Nov 18, 2020 6:56:39 GMT -8
I've been using a vermiculite concrete mix to insulate the back of our bench from the stone wall behind, and the interior of the bench to reduce the isa. So, if I've taken it in correctly, I add 20% of our garden clay, or some ground up kitty litter green clay perhaps, to the concrete it'll become refractory to 1200-1400 degrees c? Belt and braces, coat it with waterglass too!
Scientific papers state an upper limit of 1200°C for refractories with portland binder. Depending on the composition significantly more would be possible in my experience.
In my experience the portland proportion of the binder mixture may not exceed 20%, if the mixture needs to resist more than about 800°C-900°C. Bentonite which is most commonly used for kitty litter has an extreme water demand which will cause a huge lot of problems, thus do not use it. For high temperatures waterglass needs to be combined with something of high alumina content.
Vermiculite or perlite in mixtures give very weak results. Garden clay may work well if it has enough alumina and does not contain anything that may cause problems.
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Post by wrekinwanderer on Nov 18, 2020 14:37:56 GMT -8
Thanks for clarifying Karl. When you say: vermiculite or perlite in mixtures give very weak results. [/div] Does this refer to the fragility of the result? Or a poor resistance to elevated temperatures when mixed as a concrete? I ask because I'm considering using a homemade concrete of vermiculite, or perlite, as a replacement to CFB in Trev's vortex core. Hence I'm wandering in areas of high temperature, not subject to physical abrasion, whether the addition of 80% bentonite to 20% portland cement with a vermiculite/perlite aggregate, would result in a suitable insulative material for the afterburner and top chamber? Or whether better to add some CFB, or vermiculite board to the shopping list.... |
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Post by Deleted on Nov 19, 2020 2:34:09 GMT -8
Does this refer to the fragility of the result? Or a poor resistance to elevated temperatures when mixed as a concrete? It will be very fragile. Bentonite will take a huge lot of water and crack like grazy if drying. One my try a huge lot of rock wool to prevent cracking. Saving water is the way to go.
You need a Surfactant (Surface active agent also known as tenside) like Sodium Naphthalenesulfonate and a way to get a gas into the mixture, something that releases gas, a drill paddle or a foam generator.
Youtube has lots of information.
Making Foam without a Foam Generator
As a simple binder mixture you may try clay, trisodium phosphate and cement.
Aside of the USA and it's crazy prices the simplest way would be to use microballoons as an additive to get high quality porous refractory.
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Post by Orange on Nov 21, 2020 10:04:28 GMT -8
I've read that waterglass (sodium silicate)can withstand temperatures up to 1100°C. That's lower than basic CFB can withstand  |
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Post by wrekinwanderer on Nov 21, 2020 14:18:58 GMT -8
But hey, Trev recorded 900c on the vortex afterburner shelf, now he's using vermiculite board. Rated to 1100c, please correct me if I'm wrong.
So as a material to coat the CFB and contain potentially carcinogenic fibres, not bad at all...
Orange, hows your concrete waterglass test going?
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I don't think this stuff will work in my firebox at all. You've reassured me that I can still use it in the riser stub and top box. I still hesitate with my port wall since there's a ton of gas and flame pouring through this constriction and I can just imagine it weakening and stripping my fiber out with the exhaust. I do have some sodium silicate I could paint on around the port just to make sure those fiber stay bound up. 
