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Author: Subject: Homemade carbon electrodes
Hexabromobenzene
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[*] posted on 18-2-2024 at 21:35


I conducted several more experiments with electrodes with saturated polyurethane varnishes and alkyd. After pyrolysis, all of them become and sound like ceramic with a weak blow. The impregnation of thermoreactive resin turns them into a semblance of glassy carbon. Theoretically, you can bake a mixture of coal with thermorectative resin without sugar. However, thermoreactive resins are prone to cracking when heated. It is probably better to bake carbon foam from coal powder and sugar, but only then soak it with thermoreactive resin. This resembles a reinforcement of epoxy fiberglass

The more affordable composition of sugar and phosphate ammonium was founded. This glue forms a crosslinked polymer and gives 2 times more carbon than with sugar pyrolysis


[Edited on 19-2-2024 by Hexabromobenzene]
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[*] posted on 8-4-2024 at 13:26


I found a cheaper and effective replacement of binder sugar for the production of carbon electrodes!
Sugar forms only 20% carbon for pyrolysis, which is very small. Also, carbon foam from sugar has small strength
I recently found information on sugar-amino adhesives. The simplest diammonium sugar phosphate 80 20. This glue, unlike sugar, forms a crosslinked polymer and gives up to 60% carbon for pyrolysis. However, a large amount of phosphorus will be a problem when baking the carbon electrode
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6960737/

More recently, I invented my binder for electrodes based on wheat flour:

150 grams of wheat flour, 200 ml of water and 30ml 15% hydrochloric acid is mixed and heats up in a boiling water bath 10 hours .Gluten reacts with sugar in an acidic medium with the formation of soluble amino products.
During pyrolysis, this glue behaves differently than sugar or molasses made of starch. First, the excess of glucose decomposes. Then there is a reaction between sugar and dissolved protein with the formation of a crosslinked polymer, which is charred (the smell differs from the smell of burnt sugar). The result is much more carbon than from the clean sugars and it has greater mechanical strength.

For the manufacture of carbon electrodes, I recommend using this glue. However, with it will not be possible to make a whole piece of carbon without pores. To do this, you need a polymer that is become solid at a ROOM TEMPERATURE to avoid the formation of gas bubbles.


[Edited on 8-4-2024 by Hexabromobenzene]
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[*] posted on 19-4-2024 at 20:07


I experienced another binder for carbon electrodes. This time from oatmeal.
900 grams of oatmeal 1.5 liters of water and 120 ml of 15% hydrochloric acid were mixed and heat about 1 day at 90-100 degrees. The resulting liquid smells like apples and cinnamon
During filtering, it was lost up to half the solution. This is probably due to cellulose . When using wheat flour, filtration is not required

The carbonization of this solution showed that it forms significant amounts of carbon (possibly more than from wheat flour) more strong than from sugar. Unlike the binder from wheat flour during carbonization, there was no smell of burnt sugar.
This means that all glucose reacted with proteins. Wheat flour contains 80% starch and 10% protein. Oatmeal contain 70% starch and 13% protein
Probably in oatmeal, the ratio of carbohydrates and proteins closer to the stichiometric

Definitely sugar-amine binder is better than sugar for the manufacture of carbon electrodes

[Edited on 20-4-2024 by Hexabromobenzene]

[Edited on 20-4-2024 by Hexabromobenzene]
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[*] posted on 21-4-2024 at 15:13


Another binder for carbon electrodes was prepared. Gluten was extracted from 1200 grams of wheat flour using water and added to 700 grams of flour. 1000 ml of water and 100 ml of 15% hydrochloric acid were added to the gluten and flour mixture
The mixture was also heated to 90-100 degrees for 1 day. When carbonation, there was no burnt sugar smell like a binder without gluten addition flour.
The carbon produced from this binder is different from the previous one. It is less foam-like and harder than the previous 2

Conclusion: for a more complete reaction with sugars in flour, 2-3 times more protein is required than what was initially in the flour.
Bran contains a suitable ratio of proteins and sugars. There are also a lot of pentoses, which quickly form addition products with amino acids
However, lignin and cellulose residues create problems during filtration

Many strong odors are observed during the preparation of binders. Sometimes it looks like cinnamon, sometimes like parquet varnish or chipboard glue.
These are probably reaction products of Maillard reaction and similar

[Edited on 21-4-2024 by Hexabromobenzene]
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[*] posted on 1-5-2024 at 09:29


After a few more experiments, I finally understood how the binder from flour works.

After filtering of flour glue, the quality of carbon after carbonization drops sharply. The amount of carbon remains higher than after a carbonization of sugar and it is stronger. However, carbon precipitation obtained from non filtered binding from flour is very homogeneous.

A binder of whole grain flour was made. It was very viscous because of a large amount unhydrolyzed flour

So after the flour hydrolysis in the solution, the gluten suspension remains, which crosslinks sugar at a pyrolysis temperature. Therefore, it is necessary

If, during pyrolysis, the binder is pressed with a sheet of metal, then a dense carbon precipitate is obtained. I expect that electrodes of excellent quality will be made of wheat flour binder. Much better than sugar. The solution after filtering is suitable for use for impregnation of the electrode
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[*] posted on 29-6-2024 at 19:21


I made a new binder. This time I used bones extract or gelatin . 1 to 4 to sugar in weight and a little acid. This composition forms a compact layer of carbon with good shrinkage. I think this is the best option.
You can use any water -soluble organic amino acid

Is the this theme interesting to anyone?
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[*] posted on 29-6-2024 at 21:23


Quote: Originally posted by Hexabromobenzene  
Is the this theme interesting to anyone?
I'm interested enough to follow your progress,
but not enough to try myself.

As you are investigating primarily the fabrication of electrodes,
I think that you need to have a measure of electrode durability in electrolysis duty.
eg amp.hours per square centimeter.

Hardness and conductivity are good,
and probably good indicators of potential performance as an anode,
but how long will each composition survive use as an electrode?




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[*] posted on 30-6-2024 at 00:09


Interesting Artikel how the old Bunsen elements made there Carbon Anode.
https://dingler.bbaw.de/articles/ar156073.html#:~:text=Bunse...
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[*] posted on 30-6-2024 at 01:03


When I will have time, I will check the electrodes. In any case, they will work at least a day

I wrote about sugar many times. This is a bad binder. Electrodes crumble from it. This can be corrected by impregnating the workpiece of epoxy or other resin and then burn it, but it is expensive

Sugar forms 20% carbon during carbonization. Sugar-amino binders up to 50-60 and this carbon is solid and durable. This is more affordable and safer than phenol-formaldehyde resin

[Edited on 30-6-2024 by Hexabromobenzene]
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[*] posted on 30-6-2024 at 01:56


Thats why later down they used Tar as binder because lot of more carbon
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[*] posted on 30-6-2024 at 12:25


Quote: Originally posted by Hexabromobenzene  

Is the this theme interesting to anyone?

I find your work very interesting. It's an easy and affordable method to produce decent pyrolytical carbon from something as mundane as oatmeal or gelatine. It can find other applications than electrodes. For example, nozzle inserts in rocket motors.

Have you measured the density of produced carbon? How hard it to scratch?




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[*] posted on 30-6-2024 at 15:06


The workpiece obtained by baking charcoal with sugar is scratched with a fingernail. When impregnating with alkyd resin and carbonization, electrode can no longer be scratched with a fingernail. It also becomes ringing as ceramics with a slight blow

I have not made electrodes from the new binder yet. However, the remains after carbonization on the electric stove are very strong. Especially a strong last composition. Its adhesion is very strong both to metal and glass. It forms a very dense layer. The remains after heating of last composition on the glass surface I could not separate without damaging the glass. It can only be separated by a metal tool from the metal. Carbonization sugar forms a very soft foam

The density of the coal obtained is comparable with water. However, it depends on the size of the coal powder, binder and the number of impregnations


[Edited on 30-6-2024 by Hexabromobenzene]
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[*] posted on 30-6-2024 at 15:29


Here is the full preparation of the last binder.
Starch was extracted from 2.5 kilograms of flour using water. After the starch at the bottom formed layer, the water was separated and 50 ml of 18% hydrochloric acid was added to the resulting starch suspension. The suspension was heated for 8 hours at 100 degrees to the full hydrolysis of starch.
Then about 300 grams of bone glue were added to the suspension and heating lasted another 5 hours

The quality char from the composition was not exellent. Then another 600 grams of bone glue and 70 grams of old amino acid creatine were added to the mixture. Another 20 ml of hydrochloric acid and hydrozysate prepared from 1.5 kg of starch were added. The mixture was heated at 90 degrees 4 hours. After the synthesis, the binder smells like soy sauce
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[*] posted on 30-6-2024 at 16:29


Also, do not forget that adding only 1-2% iron by weight to fixed carbon leads to the formation of graphite, which is more resistant to combustion, for example. However, it will be difficult for you to remove the iron later
You can add any soluble iron salt to the binder
https://www.researchgate.net/publication/272274928_Study_on_...
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