To confirm your conclusion about the porosity and thermal insulation capacity of ground up perlite--consider fumed silica. Fumed silica is much more fine granular than how perlite usually comes, and yet it is far, far more thermally insulating than perlite. It is because it has so many porous micro-structures within the material, and such small micro pores (really a lot of surface area per given volume), that is is very efficient at stilling/trapping air molecules within its matrix. Fumed silica in on par with aeorgels in terms of thermal insulation, and is the most common core spacing material used in vacuum insulated panels (VIP's).
@@justinw1765 Thanks. I did end up looking it up. Just trying to consider ways that they could be used in the refractory without immediately leaching out.
Thanks so much. Been looking for fire brick methods. This is the best I have seen. Also lovely calm presentation. The right number of words. And thanks for the poster below for converting that to Calcium Phosphate.
Hi, Thanks again for sharing your ideas. You have got me going. Eventually, my calcium phosphate arrived (it is not so easily available in Australia). So overnight I made my first test pucks using the ratio of 270g of phosphate to 152g of lime. I made that up as a bulk-dried mix in the kitchen blender. It's OK with the boss of the kitchen because that's ME. I made three test pucks from that mix: 1. no perlite, compressed and flooded and left overnight (according to your method). I used a chunk of a railway line on a puck that was the size of a picnic tumbler! 2. as above and mixed wet (and a bit sloppy), then compressed and left overnight without compression 3 as above after mixing in an equal volume of uncrushed perlite and left overnight without compression It is early days, but this morning all the pucks were quite solid and initially had no sign of the flakiness that you describe and I think you attribute to the lack of compression. However, puck 1 (the soaked and overnight compressed puck) had a soft bottom that looked as though it had not wetted up enough to complete the reaction. As soon as I added some water to it it started to bubble, puff and flake. Luckily, this did no deep damage and it immediately went hard and left a little scar on what started as a smooth surface. They are all sitting on my winter wood stove drying slowly awaiting their baptism inside the fire. It seems that wet mixing before moulding (as suggested by TheBreaded and me) MAY be quite practical, but the reaction is quite fast as you indicate. I think there is a fast initial reaction and then a slower one that makes the final hardness of the refractory? Consequently, for my fourth puck (that I poured this morning) I had the preweighed water ready for quick addition, rapid mixing and then molding. Very easy! Best regards, Tim
Awesome! I look forward to hearing how they stand up. I think the fast reaction aspect become a bigger issue when you want to cast larger forms because you have to move a lot of material quickly. But as you mentioned, maybe there is a second stage to the curing that could give some extra time. I'll play around with that myself too. What I ended up adopting for the issue you mentioned of the dry bottom was to use something such as a cloth that can wick the water and deliver it to all the surfaces of the material.
Tim, here in Australia we can buy Richgro Super Phosphate fertiliser from Bunnings. It is Ca(H2PO4)2 the same as the hi yield triple super phosphate product, but because it has no other phosphates in it, it is up to 100% Ca(H2PO4)2 instead of the 65% wt. in the hi yield product.
Ok so the USA uses a unique system to measure phosphorus. It measures phosphorus in NPK from % of equivalent mass of P2O5 (phosphorus pentoxide). Who knows why, they just do. So NPK of 0-45-0 means that the product has 45% of the amount of elemental phosphorus as an equivalent amount of phosphorus pentoxide. Confused? Yeah… So the product has 19.64% of elemental phosphorus, so under Australian NPK labelling it’s 0-19.64-0. It’s a bloody lot of phosphorus, more than twice the amount we get in our local products. Man that had me confused.
Hi, are you sure this isn’t producing CaHPO4 with an excess of Ca(OH)2? This would explain a reaction from leaving it uncompressed (lime carbonation, and perhaps some pozzolanic reaction with SiO2 from the perlite). I was thinking that considering the hi yield product is only 65% Ca(H2PO4)2, it would either be an 8.5g excess of phosphate for Ca3(PO4)2, or a 2.4g excess of lime for CaHPO4. I’m just going into the garage now to test something, I’ll let you know how I go.
Very cool. Have you tried adding water to the mix and pouring it into a form? A few bricks seems like they'd be a nice way to make like a knife forge. If you're wanting to grind a lot of the triple phosphate and perlite up wonder if a grain mill for homebrewing may work.
Intention to inform: to much water added at the end of the mixing or in total, ruins the chemestry that has to been keep in balance. To much water and the phosphoricacid will be to thin to react with the solids used. more then 30% ruined my pours. Go and do some research on geopolymers made from Calciumoxid with phosphoricacid. Theay are a wonderful thing.
In this case the solubility of the mixture is pretty limited so that provides a very large margin of error for the water. Otherwise yes this would likely not work that well.
I'm curious if you tried adding a "reasonable" amount of regular Portland cement or simple Plaster of Paris to the mix? Seems like it might help hold it together better (?) I'd still compress it while curing though - also would be interesting to vacuum bag it, or put the whole brick mold (including weights) in a vacuum chamber. Looking forward to hitting my local harware store for some supplies :) thanks
I personally would avoid anything that solidifies strictly by hydration, such as cement. The high temperatures will dehydrate the cement. This mix that I show in the video only uses the water to diffuse the reactants so they can form the phosphate. I'm sure it's a hydrated form of it but dehydrating it will not cause the phosphate to decompose.
Hi. Thank you for making this Video. Here in the UK it's quite difficult to find Hydrated Lime but I can easly buy Calcium Hydroxide 98% powder. In what ratio should I use it with Triple Super Phosphate? Please. Thank you, Regards.
his ratio was 3.7 P / 1 C(OH) or 37 /10 I buy it in 25kg - builders merchants - NHL is the thing to ask for. 15-25 £ It's incredibly useful stuff. I just have to try my hand at forge-ery, hopefully will turn out legit.
the perlite could be graded to increase brick strength (maybe reducing the maximal temperature that can withstand before cracking). The biggest flow here, in a metallurgic case, is having unreacted hydrated lime. at 512°C, hydrated lime would become just lime, and it will reduce the volume (creating surface cracking visible in the tested surface). low amount of unreacted hydrated lime does not really matter, but large amounts of it could produce "rock slaking" during thermal cycling. to reduce the problem, you can: leave the water for longer (allowing more time to complete the reaction, but one day may not be enough) make a second stage of curing, but this time under water with some phosphate dissolved to react any remaining lime in the surface (this may take time also time, but this would reduce the problems with the surface reaching the critical temperature of 512°C, as it would not microcrack) there could be still some hydrated lime in the core of the brick, but at that point it could acts as self healing roman concrete (if water somehow manage to get there there could become powder eventually tho). most of unreacted lime would be in large granules of lime with a heavy coat of calcium phosphate. other thing: calcium phosphate is not soluble in water. but if the water is slightly acidic, you will dissolve quiet a lot. this may not be the best material to make an insulated fireplace exposed to rain (all rain is acidic).
These are all extremely good points. I had thought of trying to take care of the remaining calcium hydroxide with a bath of dilute phosphoric acid but the diffusion time would be very long. Also a good point regarding using it outdoors with exposure to rain.
I have been able to get a forge to welding temperatures with this. Theoretically it might withstand up to ~1,600 DegC but I would say that I have not formally confirmed a max temperature.
I'm working on an electric furnace using this as the insulator. A functional forge is definitely up there on my list as well. I've been occupied revamping my workshop which will hopefully be done by August and then I will have a lot more capacity to do neat things like that.
I would say there is no comparison. This is meant for very high temperatures and the plaster of paris will dehydrate and loose it's cohesion at higher temperatures.
Well done video. Thank you. "Stoichiometry"...betcha don't get to use that word every day. ;) You're a learned man: respect for that. Any idea or known value for what temps this material will withstand?
Ha ha! Well in my line of work stoichiometry comes up somewhat frequently. Theoretically it could stand up to 1,600 DegC. But I suspect there could be limitations before it reaches that. I can get it heated to forge welding temperatures without issue, so that may give a practical guide on what it can do.
Hey, after reading the comments and saw that 1.77/1 is the possibly the correct ratio, is this true, if so would you use the same procedure as shown in the video? Also do you know the weight and size/bolume of the bricks. Trying to figure an estimate of how many bricks I could forseeably make and if its worth the time(for me) thanks! Ps also is there a direct alternative for the triple super phosphate(like maybe Dicalcium or monocalcium phosphate? Not a chemistry man so I dont know the affect it would have entirely haha)? I can't get it near me anyways so if I have to order it anyways I figure I may as well get something that isn't marked up for gardening. Thanks again!
@Dritherien - I tried thit today but didnt seem to work. Vety clay like and loose. How long does the reaction take ? Imay have veen a little impatient.
The mixture does have to be compressed while it is curing, otherwise the heat/water produced during the reaction seems to cause voids to form which affects the cohesion. I usually apply some weight on top of the mixture before adding the water. It also helps if the container you use for the mold has the ability to let water soak through. The faster the water can get into the mixture the better the result. If you cannot though, then the mixture should be submerged in the water for up to 24 hours to ensure it reaches all of the mixture.
Hi, Thanks for your informative video. It is well-paced. Yes, I also have issues with my sound engineer. My chemistry is a bit rusty. I am preparing to make some of your refractory. My calcium dihydrogen phosphate is the dihydrate form, so that makes only a little difference (I think yours might be anhydrous phosphate?). I calculate my phosphate to have a mole wt of 270g/mole and the calcium hydroxide at 76g/mol. I assume that I need 1 mole of calcium phosphate and 2 moles of calcium hydroxide to get a balance acid/base reaction? So this makes the ratio 1.77 [270/(2*76)]. This is very different to your weight ratio of 3.7:1. Have I got something very wrong? I would appreciate your help. Lastly, perlite is nasty stuff even the dust from unground granules irritates your lungs. Grinding makes it much worse. It is about 60% SiO2 and that rings alarm bells about the risk of silicosis. I think I can hear you start to cough when you introduce the ground perlite, so please be careful. Thanks again Tim
Oh snap! Yes, your numbers are correct. Though one thing I have noted is that I don't think all of the calcium dihydrogen phosphate actually reacts... the stuff is super slow to dissolve, so there is likely less of it chemically available. Sorry about the slow response; apparently TH-cam decided I didn't need to be notified about comments! Yes, very good point about the perlite. And I probably was coughing due to it. I now have a fume hood of sorts and a better respirator, hopefully I can add some common sense to my PPE.
@@Drjtherrien Hi, thanks for the reply. Yes, we are at the mercy of the machine that decides what is spam and valid comments. Given the slowness of the reaction, it seems that TheBreaded's comment about mixing with water might just work? Still waiting on the delivery of my calcium phosphate. Tim
Actually the reaction is very fast. Too fast for the calcium dihydrogen phosphate to dissolve and that’s probably why the reaction still works with the stoichiometry as off as I had it; everything solidifies quickly and prevents diffusion of reactants. 🤷🏻♂️
I have been able to get a forge to welding temperatures with this. Theoretically it might withstand up to ~1,600 DegC but I would say that I have not formally confirmed a max temperature.
So bone meal is a different chemical: hydroxyapatite. If you were to use that you would need to use phosphoric acid to convert it to the calcium phosphate. I have no idea if that would work well or not.
I have wondered instead of using perlite , which is a good product. I had come up with the thought that perlite burns out lite styrofoam does, i believe anyway. Why no use a stupid cheap material because after all it is about adding air space to create its insulative effects why not us popcorn? Crush it upbif you wish but it wouldnt be a danger as it eventually burns out and other than a rodent maybe finding it. I dont believe it would be a problem by simply addind a slurry coat or a sheet metal jacket as a protector. I think it could work well and it stupid cheap...
Popcorn would probably get much denser in the process of crushing it up. But you are right that one could use something that will simply burn up; though I would worry if that would cause gasses to expand and crack the material. One thing that I could try is flour. It would burn out and leave the micron scale gas bubbles that would help with the insulation. I might give that a try.
That depends on what you mean by high temperature. Calcium in it's oxidized state is not volatile at high temperatures. The upper limit of the stability is going to be limited to the melting or decomposition temperature of the cation used. Phosphate is surprisingly stable.
I wish I could speak Hindi. Mandi kek rokker Hindustani jib... that's the closest I can do without using Google translate. That is my ancestral language which is closer to Punjabi.
To confirm your conclusion about the porosity and thermal insulation capacity of ground up perlite--consider fumed silica. Fumed silica is much more fine granular than how perlite usually comes, and yet it is far, far more thermally insulating than perlite. It is because it has so many porous micro-structures within the material, and such small micro pores (really a lot of surface area per given volume), that is is very efficient at stilling/trapping air molecules within its matrix. Fumed silica in on par with aeorgels in terms of thermal insulation, and is the most common core spacing material used in vacuum insulated panels (VIP's).
I think that is worth trying. Thank you for the suggestion.
Any idea that if it trapped a gas other than air, do you know which one's (gases) would be more insulating?
@@deucedeuce1572 There are plenty of gases with lower thermal conductivity than air. Argon, carbon dioxide, etc.
@@justinw1765 Thanks. I did end up looking it up. Just trying to consider ways that they could be used in the refractory without immediately leaching out.
@@deucedeuce1572 yeah that would be a very challenging issue to overcome.
This looks ideal for bricks for the bottom of my forge, thanks for sharing the process and giving the pitfalls too.
Thanks so much. Been looking for fire brick methods. This is the best I have seen. Also lovely calm presentation. The right number of words.
And thanks for the poster below for converting that to Calcium Phosphate.
Glad it was helpful!
Hi, Thanks again for sharing your ideas. You have got me going. Eventually, my calcium phosphate arrived (it is not so easily available in Australia). So overnight I made my first test pucks using the ratio of 270g of phosphate to 152g of lime. I made that up as a bulk-dried mix in the kitchen blender. It's OK with the boss of the kitchen because that's ME.
I made three test pucks from that mix:
1. no perlite, compressed and flooded and left overnight (according to your method). I used a chunk of a railway line on a puck that was the size of a picnic tumbler!
2. as above and mixed wet (and a bit sloppy), then compressed and left overnight without compression
3 as above after mixing in an equal volume of uncrushed perlite and left overnight without compression
It is early days, but this morning all the pucks were quite solid and initially had no sign of the flakiness that you describe and I think you attribute to the lack of compression. However, puck 1 (the soaked and overnight compressed puck) had a soft bottom that looked as though it had not wetted up enough to complete the reaction. As soon as I added some water to it it started to bubble, puff and flake. Luckily, this did no deep damage and it immediately went hard and left a little scar on what started as a smooth surface. They are all sitting on my winter wood stove drying slowly awaiting their baptism inside the fire.
It seems that wet mixing before moulding (as suggested by TheBreaded and me) MAY be quite practical, but the reaction is quite fast as you indicate. I think there is a fast initial reaction and then a slower one that makes the final hardness of the refractory?
Consequently, for my fourth puck (that I poured this morning) I had the preweighed water ready for quick addition, rapid mixing and then molding. Very easy!
Best regards, Tim
Awesome! I look forward to hearing how they stand up. I think the fast reaction aspect become a bigger issue when you want to cast larger forms because you have to move a lot of material quickly. But as you mentioned, maybe there is a second stage to the curing that could give some extra time. I'll play around with that myself too.
What I ended up adopting for the issue you mentioned of the dry bottom was to use something such as a cloth that can wick the water and deliver it to all the surfaces of the material.
Borax may slow down the reaction. It works for me pretty well with MgKPO4 cement, kind of similar, should work.
Tim, here in Australia we can buy Richgro Super Phosphate fertiliser from Bunnings. It is Ca(H2PO4)2 the same as the hi yield triple super phosphate product, but because it has no other phosphates in it, it is up to 100% Ca(H2PO4)2 instead of the 65% wt. in the hi yield product.
Yeah I was wrong, the product at bunnings says
Ok so the USA uses a unique system to measure phosphorus. It measures phosphorus in NPK from % of equivalent mass of P2O5 (phosphorus pentoxide). Who knows why, they just do. So NPK of 0-45-0 means that the product has 45% of the amount of elemental phosphorus as an equivalent amount of phosphorus pentoxide. Confused? Yeah…
So the product has 19.64% of elemental phosphorus, so under Australian NPK labelling it’s 0-19.64-0.
It’s a bloody lot of phosphorus, more than twice the amount we get in our local products.
Man that had me confused.
Another awesome video!
Hi, are you sure this isn’t producing CaHPO4 with an excess of Ca(OH)2? This would explain a reaction from leaving it uncompressed (lime carbonation, and perhaps some pozzolanic reaction with SiO2 from the perlite). I was thinking that considering the hi yield product is only 65% Ca(H2PO4)2, it would either be an 8.5g excess of phosphate for Ca3(PO4)2, or a 2.4g excess of lime for CaHPO4. I’m just going into the garage now to test something, I’ll let you know how I go.
Thank you for your ideas how calcium chloride is also make
Very cool. Have you tried adding water to the mix and pouring it into a form? A few bricks seems like they'd be a nice way to make like a knife forge. If you're wanting to grind a lot of the triple phosphate and perlite up wonder if a grain mill for homebrewing may work.
The mix reacts fairly quickly so I suspect there would not be enough time to pour it. And yes, totally agree on the grain mill idea.
Intention to inform: to much water added at the end of the mixing or in total, ruins the chemestry that has to been keep in balance. To much water and the phosphoricacid will be to thin to react with the solids used. more then 30% ruined my pours.
Go and do some research on geopolymers made from Calciumoxid with phosphoricacid. Theay are a wonderful thing.
In this case the solubility of the mixture is pretty limited so that provides a very large margin of error for the water. Otherwise yes this would likely not work that well.
I'm curious if you tried adding a "reasonable" amount of regular Portland cement or simple Plaster of Paris to the mix? Seems like it might help hold it together better (?) I'd still compress it while curing though - also would be interesting to vacuum bag it, or put the whole brick mold (including weights) in a vacuum chamber.
Looking forward to hitting my local harware store for some supplies :)
thanks
I personally would avoid anything that solidifies strictly by hydration, such as cement. The high temperatures will dehydrate the cement. This mix that I show in the video only uses the water to diffuse the reactants so they can form the phosphate. I'm sure it's a hydrated form of it but dehydrating it will not cause the phosphate to decompose.
I found this incredibly helpful for making great refractory bricks.
Do you also have a recipe for refractory cement?
Cement as in an adhesive? Unfortunately no.
Hi. Thank you for making this Video. Here in the UK it's quite difficult to find Hydrated Lime but I can easly buy Calcium Hydroxide 98% powder. In what ratio should I use it with Triple Super Phosphate? Please. Thank you, Regards.
Well you are in luck because hydrated lime is Calcium Hydroxide, so you can use the same proportions.
his ratio was 3.7 P / 1 C(OH) or 37 /10
I buy it in 25kg - builders merchants - NHL is the thing to ask for. 15-25 £
It's incredibly useful stuff.
I just have to try my hand at forge-ery, hopefully will turn out legit.
@@Drjtherrien Thank you
thanks for showing, it took me ages to learn this!!! but I know now! :)
the perlite could be graded to increase brick strength (maybe reducing the maximal temperature that can withstand before cracking). The biggest flow here, in a metallurgic case, is having unreacted hydrated lime. at 512°C, hydrated lime would become just lime, and it will reduce the volume (creating surface cracking visible in the tested surface). low amount of unreacted hydrated lime does not really matter, but large amounts of it could produce "rock slaking" during thermal cycling.
to reduce the problem, you can:
leave the water for longer (allowing more time to complete the reaction, but one day may not be enough)
make a second stage of curing, but this time under water with some phosphate dissolved to react any remaining lime in the surface (this may take time also time, but this would reduce the problems with the surface reaching the critical temperature of 512°C, as it would not microcrack)
there could be still some hydrated lime in the core of the brick, but at that point it could acts as self healing roman concrete (if water somehow manage to get there there could become powder eventually tho). most of unreacted lime would be in large granules of lime with a heavy coat of calcium phosphate.
other thing: calcium phosphate is not soluble in water. but if the water is slightly acidic, you will dissolve quiet a lot. this may not be the best material to make an insulated fireplace exposed to rain (all rain is acidic).
These are all extremely good points. I had thought of trying to take care of the remaining calcium hydroxide with a bath of dilute phosphoric acid but the diffusion time would be very long. Also a good point regarding using it outdoors with exposure to rain.
What do you think about adding fireclay as a binder? Do you think that would work?
That could work.
Thanks Sir. I will try next time. whats temperatur can holds this bricks?
I have been able to get a forge to welding temperatures with this. Theoretically it might withstand up to ~1,600 DegC but I would say that I have not formally confirmed a max temperature.
This is very useful. I would love to see this made into small furnace/forge with a ribbon burner.
I'm working on an electric furnace using this as the insulator. A functional forge is definitely up there on my list as well. I've been occupied revamping my workshop which will hopefully be done by August and then I will have a lot more capacity to do neat things like that.
How does this compare to plaster of paris/sand (or other aggregate combo)?
I would say there is no comparison. This is meant for very high temperatures and the plaster of paris will dehydrate and loose it's cohesion at higher temperatures.
Well done video. Thank you. "Stoichiometry"...betcha don't get to use that word every day. ;) You're a learned man: respect for that. Any idea or known value for what temps this material will withstand?
Ha ha! Well in my line of work stoichiometry comes up somewhat frequently. Theoretically it could stand up to 1,600 DegC. But I suspect there could be limitations before it reaches that. I can get it heated to forge welding temperatures without issue, so that may give a practical guide on what it can do.
Sir what are u making caphosphate bricks or a refractory? Look at your vlog desciption
Hey, after reading the comments and saw that 1.77/1 is the possibly the correct ratio, is this true, if so would you use the same procedure as shown in the video? Also do you know the weight and size/bolume of the bricks. Trying to figure an estimate of how many bricks I could forseeably make and if its worth the time(for me) thanks!
Ps also is there a direct alternative for the triple super phosphate(like maybe Dicalcium or monocalcium phosphate? Not a chemistry man so I dont know the affect it would have entirely haha)? I can't get it near me anyways so if I have to order it anyways I figure I may as well get something that isn't marked up for gardening. Thanks again!
Can you superphosphate instead of tripple phosphate?
Yes. I have been experimenting with that and it does work. You have to change the ratios of the phosphate to lime.
@Dritherien - I tried thit today but didnt seem to work. Vety clay like and loose.
How long does the reaction take ? Imay have veen a little impatient.
The mixture does have to be compressed while it is curing, otherwise the heat/water produced during the reaction seems to cause voids to form which affects the cohesion. I usually apply some weight on top of the mixture before adding the water. It also helps if the container you use for the mold has the ability to let water soak through. The faster the water can get into the mixture the better the result. If you cannot though, then the mixture should be submerged in the water for up to 24 hours to ensure it reaches all of the mixture.
Kindly guide me about monocalcium phosphate feed grade for poultry and animal purpose.
Ur kind response will be highly appreciated.
Hi, what would you like to know about it?
can this be used for pizza oven ?
I think it could.
Sir the uses of calcium dihydrogen phosphate
Super tripple phosphate is calcium dihydrogen phosphate, CaH4P2O8. If Ca3P2O8 is your goal add the calcium in slight excess.
That's what the lime is for, to add that extra calcium.
Is triple phosphate the same as STPP (sodium triply phosphate tech or food grade powder)?
No. The formulation I am using does not have any sodium in it. It might still work with that.
To remove from molds I'd recommend spraying the molds with a PTFE (aka Teflon) dry adhesive. Basically a "mold release."
Thanks. I do have that and will give it a try.
I want to make di calcium phosphate please give me their process
You mean the precursor that I use? I just buy it since it's a common fertilizer/farm animal supplement. I have no idea how to make it.
Hello how are you my friend can I name mixing materials and how much weight I don't understand the translation if possible ❤
The refractory is 3.7 grams of Ca(H2PO4) for every 1 gram Ca(OH). I then mix equal volume of the refractory and powdered perlite.
I hope that helps.
dismissable tip - to mix dust, try putting a lid on then rolling & shaking. let it settle a moment after.
Hi, Thanks for your informative video. It is well-paced. Yes, I also have issues with my sound engineer.
My chemistry is a bit rusty. I am preparing to make some of your refractory. My calcium dihydrogen phosphate is the dihydrate form, so that makes only a little difference (I think yours might be anhydrous phosphate?). I calculate my phosphate to have a mole wt of 270g/mole and the calcium hydroxide at 76g/mol. I assume that I need 1 mole of calcium phosphate and 2 moles of calcium hydroxide to get a balance acid/base reaction? So this makes the ratio 1.77 [270/(2*76)]. This is very different to your weight ratio of 3.7:1. Have I got something very wrong? I would appreciate your help.
Lastly, perlite is nasty stuff even the dust from unground granules irritates your lungs. Grinding makes it much worse. It is about 60% SiO2 and that rings alarm bells about the risk of silicosis. I think I can hear you start to cough when you introduce the ground perlite, so please be careful.
Thanks again Tim
Oh snap! Yes, your numbers are correct. Though one thing I have noted is that I don't think all of the calcium dihydrogen phosphate actually reacts... the stuff is super slow to dissolve, so there is likely less of it chemically available. Sorry about the slow response; apparently TH-cam decided I didn't need to be notified about comments!
Yes, very good point about the perlite. And I probably was coughing due to it. I now have a fume hood of sorts and a better respirator, hopefully I can add some common sense to my PPE.
@@Drjtherrien Hi, thanks for the reply. Yes, we are at the mercy of the machine that decides what is spam and valid comments. Given the slowness of the reaction, it seems that TheBreaded's comment about mixing with water might just work? Still waiting on the delivery of my calcium phosphate. Tim
Actually the reaction is very fast. Too fast for the calcium dihydrogen phosphate to dissolve and that’s probably why the reaction still works with the stoichiometry as off as I had it; everything solidifies quickly and prevents diffusion of reactants. 🤷🏻♂️
The awful noise ends around 7:00, for those who have ripped their headphones off their heads or lunged for the speaker to make it stop
Okay it appears there are a few brief aftershocks
Never mind it restarts around 9:00 better keep the volume down the whole video.
Ooops my bad. I will have to go back over the audio on this.
What’s the highest temp can it withstand?
I have been able to get a forge to welding temperatures with this. Theoretically it might withstand up to ~1,600 DegC but I would say that I have not formally confirmed a max temperature.
@@Drjtherrien thx I think I’ll try this mix for my next foundry I make when my old one goes
And could i just use bone meal fertilizer as the phosphate?
What about d dextromise Earth or DE?
So bone meal is a different chemical: hydroxyapatite. If you were to use that you would need to use phosphoric acid to convert it to the calcium phosphate. I have no idea if that would work well or not.
Make them enterlock like a lego kinda !
I have wondered instead of using perlite , which is a good product. I had come up with the thought that perlite burns out lite styrofoam does, i believe anyway. Why no use a stupid cheap material because after all it is about adding air space to create its insulative effects why not us popcorn? Crush it upbif you wish but it wouldnt be a danger as it eventually burns out and other than a rodent maybe finding it. I dont believe it would be a problem by simply addind a slurry coat or a sheet metal jacket as a protector.
I think it could work well and it stupid cheap...
Popcorn would probably get much denser in the process of crushing it up. But you are right that one could use something that will simply burn up; though I would worry if that would cause gasses to expand and crack the material. One thing that I could try is flour. It would burn out and leave the micron scale gas bubbles that would help with the insulation. I might give that a try.
Nothing with calcium is going to be very high temp.
That depends on what you mean by high temperature. Calcium in it's oxidized state is not volatile at high temperatures. The upper limit of the stability is going to be limited to the melting or decomposition temperature of the cation used. Phosphate is surprisingly stable.
Don’t mix while your talking it makes it harder to hear what your saying
Thank you for the comment. It is a good point.
Hindi language me
I wish I could speak Hindi. Mandi kek rokker Hindustani jib... that's the closest I can do without using Google translate. That is my ancestral language which is closer to Punjabi.
Talkalot Doolittle