Thank you for the videos on making the lightweight refractory material. I was looking into building a small kiln for a microwave oven, so this recipe will certainly be a great help. The specific question I have is on joining/ glueing pieces of this material. Do you have an idea on a recipe that will work? Thank you!
Depending on the temperature you want to reach, furnace cement would be a decent choice (it's typically good up to ~1,100 DegC). There are specialty mortars that can go higher. Depending on where you are, I have bought some from McMaster Carr. I have also experimented with using the same refractory material in the video for joining parts but it had mixed results.
@@Drjtherrien thank you for your answer. I am not familiar with the brandname in my country, but I am familiar with the high temperature joining paste up to 1100 degrees Celsius.
I have not. My main goal here was the make something that had the least amount of fiddling with chemical reactions. I have thought about trying to add some aluminum oxide to improve the high temperature limit.
I have a random question. I am welder fabricator with no chemistry background. Could you supplement the perlite with potash as a cheaper alternative in your refractory mix? I've been experimenting with glass water and potash to make a refractory brick, and it seems to be working well though I haven't been able to put much time into it yet? Have only been giving it the blow torch treatment on the workbench. Thank you for the videos.
I use the perlite to provide thermal insulation. That and it should handle higher temperatures than potash. That being said, if you are aiming to use water glass the potash would be compatible with that. You still want to have something to increase the thermal insulation.
I was thinking about creating small air pockets by adding a small amount of sawdust evenly spread through the mixture that would burn out leaving airports. I saw another guy do this when making clay fire bricks.
Is there any possibility of developing a refractory based on MgO or SiO². I would like to get into cast iron and Ca³(PO⁴)² melts at 1670°C which is a bit close for my liking. Awesome recipe. By far the best I've seen on TH-cam (most use Portland cement😢). I've seen a couple of good geopolymers but were harder to source the raw materials.
Well thank you! I was considering MgO since that's not too awful to source. If I recall right the big issue was that exposure to moisture was going to be a potential issue as the MgO would convert to Mg(OH)2 and back to MgO when heated. I imagine the volume change would cause a lot of spalling in the ceramic. SiO2... maybe you meant Al2O3? Silicon dioxide melts well below what Calcium phosphate can withstand. I have considered trying to use some alumina sand blasting powder as a surface treatment but have not gotten around to trying it.
@@Drjtherrien Intention to inform. Aluminium powder will induce bubbles when mixed into the mix. As soon the phosphates are leached out with the water the phosphoricacid formed will attack the aluminium and then produce pores. A standard recpie is: 1 : 0,6 parts and some water to get going Wollstonite + Phosphoricacid 40-60% (the higher the content the longer the acid will nagg at the silicate and wont get hard. The reaction goes on for days when not weeks we stoped the experiment after 4 days by just mixing in 30% water. The idea of the water is that it functions as a ion-transferfluid. Then can the free ion exchange between the substances and form a new group) 1. You ad 80g Wollstonite to a 200ml container, the stuff will foam up about 3x its volume and then go back 2. then ad some water and mix that to a very thick slurry. As thick as possible. You dont want a very high water content in the mix because that makes the drying time longer and the result more brittle. 3. Then you ad the phosphoricacid to the paste and stirr it very good, dont spill it over, it will foam up very. The colder the water used the less bubbles will be formed. When you add aluminiumpowder it will form bubbles to. 4. now we are entering the casting phase, when the bubbles go away you have about 30 seconds to cast the stuff. You will get a foamy ceramic like concrete. That insulates extremely well. You can pour the part into a foam and then inducing it to a vacuum chamber and getting the bubbles out, when the vacuum can be formed fast enough. Maybe by adding borax it will be longer fluid. But i would have to test that to. When you add some flyash as filler you have a +-2000°C refractory cement. You can also take metakaolin and mixing potassium waterglass in it BUT the silizium content has to be 1,75 Si to 1 part Kalium to get very good results. you can but concrete sealing waterglass based on Kalium that is cheap and works to. More recipes can be found in Davidovits geopolymer book.
@Drjtherrien, what method did you use to compress the refractory tube?
Thank you for the videos on making the lightweight refractory material. I was looking into building a small kiln for a microwave oven, so this recipe will certainly be a great help. The specific question I have is on joining/ glueing pieces of this material. Do you have an idea on a recipe that will work?
Thank you!
Depending on the temperature you want to reach, furnace cement would be a decent choice (it's typically good up to ~1,100 DegC). There are specialty mortars that can go higher. Depending on where you are, I have bought some from McMaster Carr. I have also experimented with using the same refractory material in the video for joining parts but it had mixed results.
@@Drjtherrien thank you for your answer. I am not familiar with the brandname in my country, but I am familiar with the high temperature joining paste up to 1100 degrees Celsius.
@@Drjtherrien So I will try that first and let you know how it held up.
Thanks again!
@@janhuizer5382 Great! I will be interested to hear how it goes.
Have you tried the aluminum foil and sodium silicate reaction? (makes alumino silicates, I think?).
I have not. My main goal here was the make something that had the least amount of fiddling with chemical reactions. I have thought about trying to add some aluminum oxide to improve the high temperature limit.
I have a random question. I am welder fabricator with no chemistry background. Could you supplement the perlite with potash as a cheaper alternative in your refractory mix? I've been experimenting with glass water and potash to make a refractory brick, and it seems to be working well though I haven't been able to put much time into it yet? Have only been giving it the blow torch treatment on the workbench.
Thank you for the videos.
I use the perlite to provide thermal insulation. That and it should handle higher temperatures than potash. That being said, if you are aiming to use water glass the potash would be compatible with that. You still want to have something to increase the thermal insulation.
I was thinking about creating small air pockets by adding a small amount of sawdust evenly spread through the mixture that would burn out leaving airports. I saw another guy do this when making clay fire bricks.
@@LittleAussieRockets Why not ground up styrofoam?
@@Drjtherrien True! thanks
هلو يا معلم رائع ممكن سؤال هل يوجد ماده لاسق صنع بوتقه نار حتى يتماسك
يصلب هذا الخليط بسرعة كبيرة. أنها لا تحتاج إلى الموثق. أستخدم الورق المقوى للدعم عند التصنيع.
يرجى عذر أي أخطاء الترجمة. شكرًا لك.
Is there any possibility of developing a refractory based on MgO or SiO². I would like to get into cast iron and Ca³(PO⁴)² melts at 1670°C which is a bit close for my liking. Awesome recipe. By far the best I've seen on TH-cam (most use Portland cement😢). I've seen a couple of good geopolymers but were harder to source the raw materials.
Well thank you! I was considering MgO since that's not too awful to source. If I recall right the big issue was that exposure to moisture was going to be a potential issue as the MgO would convert to Mg(OH)2 and back to MgO when heated. I imagine the volume change would cause a lot of spalling in the ceramic.
SiO2... maybe you meant Al2O3? Silicon dioxide melts well below what Calcium phosphate can withstand. I have considered trying to use some alumina sand blasting powder as a surface treatment but have not gotten around to trying it.
@@Drjtherrien Intention to inform.
Aluminium powder will induce bubbles when mixed into the mix. As soon the phosphates are leached out with the water the phosphoricacid formed will attack the aluminium and then produce pores.
A standard recpie is:
1 : 0,6 parts and some water to get going
Wollstonite + Phosphoricacid 40-60% (the higher the content the longer the acid will nagg at the silicate and wont get hard. The reaction goes on for days when not weeks we stoped the experiment after 4 days by just mixing in 30% water. The idea of the water is that it functions as a ion-transferfluid. Then can the free ion exchange between the substances and form a new group)
1. You ad 80g Wollstonite to a 200ml container, the stuff will foam up about 3x its volume and then go back
2. then ad some water and mix that to a very thick slurry. As thick as possible. You dont want a very high water content in the mix because that makes the drying time longer and the result more brittle.
3. Then you ad the phosphoricacid to the paste and stirr it very good, dont spill it over, it will foam up very. The colder the water used the less bubbles will be formed. When you add aluminiumpowder it will form bubbles to.
4. now we are entering the casting phase, when the bubbles go away you have about 30 seconds to cast the stuff.
You will get a foamy ceramic like concrete. That insulates extremely well. You can pour the part into a foam and then inducing it to a vacuum chamber and getting the bubbles out, when the vacuum can be formed fast enough.
Maybe by adding borax it will be longer fluid. But i would have to test that to.
When you add some flyash as filler you have a +-2000°C refractory cement.
You can also take metakaolin and mixing potassium waterglass in it BUT the silizium content has to be 1,75 Si to 1 part Kalium to get very good results.
you can but concrete sealing waterglass based on Kalium that is cheap and works to.
More recipes can be found in Davidovits geopolymer book.