It looks like a waterglass treated cellulose fiber displacer could have potential.
https://youtu.be/5QbF2cgTGJ8
It may not be completely indestructible repeatedly hit with a direct flame to glowing red hot, but as a displacer only subject to indirect heat inside the engine it may hold up ok.
Probably worth some further experimenting with.
High temperature displacer
Re: High temperature displacer
An LTD displacer size disk cut out of a pizza box lid weighs barely 2 grams. The digital readout was actually fluctuating between 1 and 2 grams.
I'm sure soaking it in water glass will increase the weight considerably, but by how much?
We will know when it dries out, which may take a few days.
- Resize_20230525_000224_4305.jpg (258.37 KiB) Viewed 12268 times
We will know when it dries out, which may take a few days.
Re: High temperature displacer
Hanging up to dry:
I'm a little concerned though, the full strength waterglass did not seem to wet the cardboard at all. That is, it does not appear to have soaked into the fibers like it did with the paper bag, turning the paper dark.
Maybe it should be thinned out with water so it will penetrate better, or maybe it will soak in more as it dries. Anyway, I can always try again with a dilute solution, but for now I'm just going to wait and see what happens.
- Resize_20230525_003323_3289.jpg (261.58 KiB) Viewed 12266 times
I'm a little concerned though, the full strength waterglass did not seem to wet the cardboard at all. That is, it does not appear to have soaked into the fibers like it did with the paper bag, turning the paper dark.
Maybe it should be thinned out with water so it will penetrate better, or maybe it will soak in more as it dries. Anyway, I can always try again with a dilute solution, but for now I'm just going to wait and see what happens.
Re: High temperature displacer
The piece of waterglass coated corrugated cardboard has completely dried overnight. It did darken the cardboard some, but has also dried with a high gloss finish, giving me the impression it did not really soak in completely.
The waterglass coating doubled the weight, but that's still only 4 grams. The cardboard, though, is 1/3rd the thickness of the 3 gram stock styrofoam.
As for being heat resistant, That has yet to be tested.
- Resize_20230525_104111_1782.jpg (165.72 KiB) Viewed 12261 times
The waterglass coating doubled the weight, but that's still only 4 grams. The cardboard, though, is 1/3rd the thickness of the 3 gram stock styrofoam.
As for being heat resistant, That has yet to be tested.
Re: High temperature displacer
It did not completely disintegrate fired in the kiln to over 1000°F
https://youtu.be/upoPVvf4PYU
As far as weight; it did not register any weight on the kitchen scale.
https://youtu.be/upoPVvf4PYU
As far as weight; it did not register any weight on the kitchen scale.
- Resize_20230525_122347_7161.jpg (251.62 KiB) Viewed 12255 times
Re: High temperature displacer
Previously I had tried a variety of carbon fiber products, but anything rigid enough to use as a displacer was bonded together with a flammable resin and this defeated the purpose.
Having become familiar with water glass as a kind of refractory glue I've decided to give carbon fiber another try, but this time, I think I found what appears to be just plain carbon fiber cloth. A rather floppy material, pretty useless as a displacer, by itself, but perhaps it could be made into a board using water glass rather than resin.
Having become familiar with water glass as a kind of refractory glue I've decided to give carbon fiber another try, but this time, I think I found what appears to be just plain carbon fiber cloth. A rather floppy material, pretty useless as a displacer, by itself, but perhaps it could be made into a board using water glass rather than resin.
Re: High temperature displacer
This is interesting, I came across while looking for sources and information about carbon fiber.
https://youtu.be/BKp5JcxFdrM
The video, however is 15 years old, the company changed hands and the number at the end of the video is no longer valid.
At this point in time, it appears this stuff is being manufactured for the aerospace industry (space-X etc.) So, in trying to get some of this foam, you may leave your name on some answering machine in West Virginia someplace is as far as I've gotten
Anyway, it is just pyrolyzed carbon foam apparently, so should be no real problem for the dedicated DIY person.
Maybe I was on the right track when I ground up some anthracite from my goal bin as a foaming agent to make foamed glass.
That didn't turn out too bad.
And this other weird stuff was basically coal powder and whatever bonded it together, I suppose the sodium silicate.
Anyway this foam, according to what information I can glean from the videos and website is just a foam made from coal that is then pyrolyzed by heating it in an oxygen free environment.
It will eventually decompose somewhat when repeatedly subject to high temperatures in an oxygen environment, but in a Stirling engine filled with an inert gas such as helium, it should last indefinitely
https://youtu.be/BKp5JcxFdrM
The video, however is 15 years old, the company changed hands and the number at the end of the video is no longer valid.
At this point in time, it appears this stuff is being manufactured for the aerospace industry (space-X etc.) So, in trying to get some of this foam, you may leave your name on some answering machine in West Virginia someplace is as far as I've gotten
Anyway, it is just pyrolyzed carbon foam apparently, so should be no real problem for the dedicated DIY person.
Maybe I was on the right track when I ground up some anthracite from my goal bin as a foaming agent to make foamed glass.
That didn't turn out too bad.
- Resize_20230510_023123_3785.jpg (118.94 KiB) Viewed 12245 times
And this other weird stuff was basically coal powder and whatever bonded it together, I suppose the sodium silicate.
- Resize_20230501_061643_3781.jpg (173.2 KiB) Viewed 12245 times
Anyway this foam, according to what information I can glean from the videos and website is just a foam made from coal that is then pyrolyzed by heating it in an oxygen free environment.
It will eventually decompose somewhat when repeatedly subject to high temperatures in an oxygen environment, but in a Stirling engine filled with an inert gas such as helium, it should last indefinitely
Re: High temperature displacer
An interesting development.
Reading through various carbon foam patents, some are manufactured through pyrolyzing polyurethane foam, but at least one patent mentions a "preferred" pyrolyzed phenolic foam.
One type of phenolic foam apparently, is that very common floral foam.
A flame test of floral foam ruled it out for consideration a long time ago, but It had never crossed my mind that the stuff could be pyrolyzed.
The temperatures involved are rather modest, in a range from about 600°C up to thousands of degrees.
Apparently it should be heated very gradually in an oxygen free environment.
Coal is useful it seems, for absorbing oxygen if placed in a container with the material to be pyrolyzed.
The foam will shrink, but as floral foam is available in large blocks, that may not be a problem.
Alternatively, two part polyurethane foam is readily available, which can be mixed to fill a mold with foam or I suppose, just an old couch cushion or polyurethane pillow might be used.
I already have several pieces of the green floral foam that's just been sitting on the shelf.
Of course, I imagine the stuff is likely to produce some toxic fumes when pyrolyzed.
Not sure if it actually has any real advantage over a loaf of sourdough, but is probably worth a try.
https://youtu.be/L-qOIO6IQWk
Back to the burnt pancake displacer: viewtopic.php?f=1&t=2133&p=10325&hilit= ... ast#p10325
Reading through various carbon foam patents, some are manufactured through pyrolyzing polyurethane foam, but at least one patent mentions a "preferred" pyrolyzed phenolic foam.
One type of phenolic foam apparently, is that very common floral foam.
A flame test of floral foam ruled it out for consideration a long time ago, but It had never crossed my mind that the stuff could be pyrolyzed.
The temperatures involved are rather modest, in a range from about 600°C up to thousands of degrees.
Apparently it should be heated very gradually in an oxygen free environment.
Coal is useful it seems, for absorbing oxygen if placed in a container with the material to be pyrolyzed.
The foam will shrink, but as floral foam is available in large blocks, that may not be a problem.
Alternatively, two part polyurethane foam is readily available, which can be mixed to fill a mold with foam or I suppose, just an old couch cushion or polyurethane pillow might be used.
I already have several pieces of the green floral foam that's just been sitting on the shelf.
Of course, I imagine the stuff is likely to produce some toxic fumes when pyrolyzed.
Not sure if it actually has any real advantage over a loaf of sourdough, but is probably worth a try.
https://youtu.be/L-qOIO6IQWk
Back to the burnt pancake displacer: viewtopic.php?f=1&t=2133&p=10325&hilit= ... ast#p10325
Re: High temperature displacer
I went over to where I had some things stored, the floor above the workshop, and found the canisters!!
It's already the end of the day though, and have another project going, but what I went to look for was the various types of floral foam I had purchased a long time ago.
While over there I cut down a canister to make flat round canister that could fit in the microwave kiln to try pyrolyzing the different materials in
While out I stopped at the dollar store and looked for polyurethane sponges. I was able to find some that were clearly marked:
If the pyrolysis process works with a common polyurethane sponges or the floral foam to make a good carbon foam I'll be happy with that I think. Soon see what happens.
It's already the end of the day though, and have another project going, but what I went to look for was the various types of floral foam I had purchased a long time ago.
- Resize_20230526_205323_3287.jpg (185.4 KiB) Viewed 12198 times
While over there I cut down a canister to make flat round canister that could fit in the microwave kiln to try pyrolyzing the different materials in
- Resize_20230526_205322_2197.jpg (192.68 KiB) Viewed 12198 times
While out I stopped at the dollar store and looked for polyurethane sponges. I was able to find some that were clearly marked:
- Resize_20230526_205323_3872.jpg (179.82 KiB) Viewed 12198 times
If the pyrolysis process works with a common polyurethane sponges or the floral foam to make a good carbon foam I'll be happy with that I think. Soon see what happens.
Re: High temperature displacer
The dollar store polyurethane sponge... Well?
It apparently vaporized.
At least there was not enough of it left to actually identify. Kind of what I would have expected before reading the patent(s). Not sure what the trick to this process might be. I had much, much better results using an ordinary slice of bread.
https://youtu.be/GwD56TGOb1I
There is still the floral foam to try.
I really did not understand how this could work, since it does not seem polyurethane actually has much carbon content.
Maybe if the sponge were first soaked with sugar water or impregnated with wheat paste of some other carbohydrate type paste or liquid then dried before being pyrolyzed.
A Wikipedia article mentions:
It apparently vaporized.
At least there was not enough of it left to actually identify. Kind of what I would have expected before reading the patent(s). Not sure what the trick to this process might be. I had much, much better results using an ordinary slice of bread.
https://youtu.be/GwD56TGOb1I
There is still the floral foam to try.
I really did not understand how this could work, since it does not seem polyurethane actually has much carbon content.
Maybe if the sponge were first soaked with sugar water or impregnated with wheat paste of some other carbohydrate type paste or liquid then dried before being pyrolyzed.
A Wikipedia article mentions:
So at least some "fluorinated polyurethanes" have a carbon element, apparently not much in a dollar store sponge though....fluorinated polyurethanes contain a high percentage of fluorine–carbon bonds, which are the strongest bonds among all chemical bonds, fluorinated polyurethanes exhibit resistance to UV, acids, alkali, salts, chemicals, solvents, weathering, corrosion, fungi and microbial attack. These have been used for high performance coatings and paints.[21]
https://en.m.wikipedia.org/wiki/Polyurethane
Re: High temperature displacer
While eating a bowl of cereal for a late breakfast, I commented to my wife that it was good to get some food in my stomach, but I can't say it's really all that much food, the puffed rice is mostly just a lot of air.
To which she responded; "you should use that for your displacer".
She says she was just joking, but I spent the next ten minutes trying to explain why it was a great idea.
Rice is rich in carbohydrates/carbon.
Like bread, it could probably be pyrolyzed, but no need to be concerned about making it rise evenly with yeast into just the right size and shape, it's already "puffed", just glue it together with some sugar syrup, like a Rice Krispies Treat:
pack it into a form to make whatever shape you want.
I don't think it could be any worse than the polyurethane sponge idea anyway. It might actually be worth a try.
To which she responded; "you should use that for your displacer".
She says she was just joking, but I spent the next ten minutes trying to explain why it was a great idea.
Rice is rich in carbohydrates/carbon.
Like bread, it could probably be pyrolyzed, but no need to be concerned about making it rise evenly with yeast into just the right size and shape, it's already "puffed", just glue it together with some sugar syrup, like a Rice Krispies Treat:
- images.jpeg (8.74 KiB) Viewed 12139 times
pack it into a form to make whatever shape you want.
I don't think it could be any worse than the polyurethane sponge idea anyway. It might actually be worth a try.
Re: High temperature displacer
Earlier in the thread I had the idea of using some kind of alcohol based gel similar to Orbeez that could be used to create voids in cement, plaster or clay to make a lightweight displacer.
Well, I had no idea about how to make an alcohol based gel, so that idea never went anywhere.
Incidentally, a similar process is used for making aerogel.
Anyway a few days ago I showed these calcium acetate crystals I had made using alcohol and agricultural lime.
My original intention was to use the calcium acetate crystals as a sky cooling paint pigment, but I was curious what else it might be useful for and came across the fact that mixed with a little water and some alcohol, the calcium acetate turns into a gel.
Apparently this gel is the same thing as Sterno fuel.
Another interesting characteristic of calcium acetate is that when heated, it releases acetone, which is also flammable.
https://youtu.be/fYm2-RqvZgk?si=tFn__r_jOhzjG3Wj
One thing I'm curious to find out is if this could somehow be a basis for some kind of aerogel-like lightweight fireproof material, maybe by using a sodium silicate (water glass) solution instead of plain water to form the gel.
Anyway, at minimum, a relatively simple method of making your own Sterno might be useful.
There are many more videos on how to make this "flaming snow". Without the blue dye, the gel looks like slush and if you keep adding a little more of the calcium acetate solution the gel will crystalize more and look more like white snow.
https://youtu.be/QHL6ZfNqZXE?si=Z5qgInpHIriSbp6J
More experimenting to do.
Well, I had no idea about how to make an alcohol based gel, so that idea never went anywhere.
Incidentally, a similar process is used for making aerogel.
Anyway a few days ago I showed these calcium acetate crystals I had made using alcohol and agricultural lime.
- Resize_20230820_224737_7880.jpg (204.5 KiB) Viewed 10836 times
My original intention was to use the calcium acetate crystals as a sky cooling paint pigment, but I was curious what else it might be useful for and came across the fact that mixed with a little water and some alcohol, the calcium acetate turns into a gel.
Apparently this gel is the same thing as Sterno fuel.
Another interesting characteristic of calcium acetate is that when heated, it releases acetone, which is also flammable.
https://youtu.be/fYm2-RqvZgk?si=tFn__r_jOhzjG3Wj
One thing I'm curious to find out is if this could somehow be a basis for some kind of aerogel-like lightweight fireproof material, maybe by using a sodium silicate (water glass) solution instead of plain water to form the gel.
Anyway, at minimum, a relatively simple method of making your own Sterno might be useful.
There are many more videos on how to make this "flaming snow". Without the blue dye, the gel looks like slush and if you keep adding a little more of the calcium acetate solution the gel will crystalize more and look more like white snow.
https://youtu.be/QHL6ZfNqZXE?si=Z5qgInpHIriSbp6J
More experimenting to do.