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mericad193724
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[*] posted on 5-12-2006 at 19:14
make carbon electrodes?


Is it possible to make your own carbon electrode for electrolysis experiments from the reaction of sugar and sulfuric acid....which makes carbon and steam. IIRC the carbon remaining is pretty pure. I have never done this experiment. In the videos I have seen the carbon forms a tower of foam which has a high surface area and can be made into sheets, rods, etc.

My question is does the carbon solidify upon cooling and become hard or is it fragile and useless??? If it becomes hard and stiff, this may be worth a try!

Mericad
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bereal511
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[*] posted on 5-12-2006 at 21:27


It's pretty much fragile and useless. The steam from the water formed creates so many air bubbles in the carbon that it's like a brittle sponge that eventually just collapses over.



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[*] posted on 5-12-2006 at 22:02


Why not use regular auto or truck generator or starter brushes as carbon electrodes....they seem to be pretty solid and are cheap.......solo



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jimmyboy
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[*] posted on 6-12-2006 at 00:51


you want graphite rods which cant be made really... your pretty much stuck there..
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Biginelli
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[*] posted on 9-12-2006 at 04:17


Pencils?
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Biginelli
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[*] posted on 9-12-2006 at 04:18


Or, perhaps, batteries? Some of D-type have graphite rods inside...
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j_smith
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[*] posted on 9-12-2006 at 07:40


The 6 volt lantern batteries have nice carbon rods in them.
Just be sure to get the carbon-zinc type of battery. They're very common.
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UnintentionalChaos
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[*] posted on 10-12-2006 at 00:01


The stuff you're looking for is in carbon-zinc dry cell batteries. These are usually the "batteries included" batteries when you buy things. The last ones i pulled apart had the following structure: a steel sheet was wrapped around a plastic sheath. Under the sheath is a zinc "shell" around a paper lining, which surrounds the gooey insides which is mostly manganese dioxide and ammonium chloride. In the center is the carbon rod you are looking for. To open it up, crush the stainless steel shell with pliers until the seam is bent open and you can pry the whole thing off. Use a small pair of scissors to cut the plastic sheath away and remove the metal cap which covers the end of the carbon rod. Pliers can now be used to extract the rod. The manganese dioxide paste is very sticky and the rod will require washing and a light sanding to clean off completely. The manganese dioxide is easier to recover from alkaline batteries, so I just throw the dry cell paste away. In order to keep the paste from adhering to everything (it is very sticky and water repellant) i cover my hands, the pliers, and scissors with liquid soap. Afterward, everything washes away nicely. Cut the zinc casing down the side (it is quite soft) with the scissors and scoop out the paper sheath and paste. Save the zinc sheeting and carbon electrodes. I used AA batteries and got nice electrodes. The lantern batteries should provide a few very large carbon rods if you were to dissect one.
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mericad193724
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[*] posted on 10-12-2006 at 08:57


I have used carbon rods from batteries before, but its just not economical and the rods are short.

Is it possible to make an electrode by using activated carbon available from the pet stores? What you would do is make a layer of activated carbon about 2 cm thick on the bottom of the electrolysis vessel and electrically contact just part of the carbon layer. Theoretically all the activated carbon granules, which are about 1cm^3 would be in contact with each other and make one big electrode.

Does this seem plausible???

Would the fact that the carbon is activated mess up experiments since it absorbs other chemicals?

thanks

Meriad
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12AX7
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[*] posted on 10-12-2006 at 09:56


The only way you can make a reasonable chunk of graphite is by recrystallizing it upwards of 2000C, obviously in a reducing atmosphere. Electric (resistance), induction and arc furnaces are used industrially.

Charcoal isn't necessarily conductive. YMMV. Hard wood that's been burned to at least yellow heat has enough graphite content to be conductive, but don't expect it to hold up for long.

By far, the easiest and cheapest source is welding shops (gouging rods), glass working (used for molds, working surfaces, tools, etc.) and bulk (esp. surplus or scrap on eBay).

Tim




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UnintentionalChaos
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[*] posted on 17-12-2006 at 22:30


I came across something by accident today involving the carbon electrodes from batteries. It appears, that in an effert to prevent the electrolyte from permeating them, the electrodes have been treated with some kind of wax, then cleaned off on the surface. If you hold a carbon rod from a battery in a butane torch flame (or similar heating device), the carbon will appear to become wet. Further heating will ignite the liquid, which smells quite like a candle being blown out (there is a lot of smoke along with the flame when using a small torch). I continued "burning" the carbon rod until it stopped smoking. I wonder how it will preform now in electrolysis as opposed to before. It surely has more available surface area at this point with the wax removed (wax was not visible at all previously and electrodes were faring only decently in performing electrolysis).
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darkurza
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[*] posted on 3-1-2007 at 21:44


According to http://www.scitoys.com/ you can just pull them out of batteries.
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[*] posted on 3-1-2007 at 22:00


yes i noticed that too a few weeks ago also by accident!

i have now burned all the wax off my electrodes, however i have been using them for months and it doesnt seem to have effected them at all, as i see no noticable improvement in the quantity of their production! before i took the torch to them they seemed cleaner and didn't flake off near as much, so perhaps the purpose of the wax was to prolong their life and prevent them from breaking down as quickly?
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UnintentionalChaos
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[*] posted on 3-1-2007 at 22:38


Now that I think about it, you may have a point. At least for low temperature applications. Anything hot and you'll have paraffin melting into whatever you're using them for or for extremely high temperatures you'll end up with unnecessary flare ups and splattering . I did find a nice source for graphite, precut nice and thin and flat. Look around for what are probably heatproof washers (Definetly washers at any rate). They are nice, 1/8 inch thick disks with a small hole in the center for a bolt to go through. I got mine for 15 cents a piece at an army surplus store, though the owner kindly sold all 16 of them $2. :D Each one gives me 12.76 square inches (82.3 square centimeters) of surface area. Chlorate cell, here I come!
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[*] posted on 4-1-2007 at 00:27


Quote:
Originally posted by b_d_Dom
yes i noticed that too a few weeks ago also by accident!

i have now burned all the wax off my electrodes, however i have been using them for months and it doesnt seem to have effected them at all, as i see no noticable improvement in the quantity of their production! before i took the torch to them they seemed cleaner and didn't flake off near as much, so perhaps the purpose of the wax was to prolong their life and prevent them from breaking down as quickly?


This wax is there for purpose. Graphite electrodes for electrochemical devices are often impregnated with lineseed oil or other material to fill small pores. This prolongs electrode life and allows to use somewhat higher current densities. Impregnating is usually done by placing electrodes below warm oil layer in vacuum environment for some time and can be done at home as well.

[Edited on 4-1-2007 by chromium]




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Aqua_Fortis_100%
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[*] posted on 4-1-2007 at 11:45


Quote:

originally posted by UnintentionalChaos :
The stuff you're looking for is in carbon-zinc dry cell batteries. These are usually the "batteries included" batteries when you buy things. The last ones i pulled apart had the following structure: a steel sheet was wrapped around a plastic sheath. Under the sheath is a zinc "shell" around a paper lining, which surrounds the gooey insides which is mostly manganese dioxide and ammonium chloride. In the center is the carbon rod you are looking for. To open it up, crush the stainless steel shell with pliers until the seam is bent open and you can pry the whole thing off. Use a small pair of scissors to cut the plastic sheath away and remove the metal cap which covers the end of the carbon rod. Pliers can now be used to extract the rod. The manganese dioxide paste is very sticky and the rod will require washing and a light sanding to clean off completely. The manganese dioxide is easier to recover from alkaline batteries, so I just throw the dry cell paste away. In order to keep the paste from adhering to everything (it is very sticky and water repellant) i cover my hands, the pliers, and scissors with liquid soap. Afterward, everything washes away nicely. Cut the zinc casing down the side (it is quite soft) with the scissors and scoop out the paper sheath and paste. Save the zinc sheeting and carbon electrodes. I used AA batteries and got nice electrodes. The lantern batteries should provide a few very large carbon rods if you were to dissect one.


Wow, mine carbon electrodes are also from same stuff, but i save ALL of carbon-zinc dry cell baterries... the steel sheet i usually use to test "micro" shaped charges which i make sometimes, the Impure manganese dioxide , i throw in muriatic acid in outside(releases nasty chlorine gas which i even use to bubble in NaOH solution to helps when i make chlorate by NaClO route) and let reacting, then after reacted i add NaOH and precipite the manganese hydroxide which i put in a pan, heat, and recover more pure MnO2 (thermite,etc but i heard which this font isn't a very good thing because which if MnO2 still contaminated with KOH then can ignites accidentaly a thermite by Al/KOH reaction. but i still dont have any accidents); the zinc "shell" is also useful...

about the carbon rod, my only problem is which sometimes its broken when i try remove it (specially the 1.5 small batteries). but when i remove one undamaged, put in HCl to remove KOH,MnO2 and other impurities and whash with water after..about the wax coating, i dont have much worry about this because mine cells works very good when i put in anything to electrolyse.. but as chromium said the linseed oil is really a good thing to increases electrode life...
you can, also use PbO2 for chlorates and even perchlorates(which carbon rods does not support)..but the disadvantage ,obviously is risk of poisoning, and (maybe) more hard obtain this..

about carbon rods another really GOOD source is the welding shop ("gouging rods" or something), but this comes wrapped in a copper "foil" which is very easy to remove..(see this: http://www.frogfot.com/synthesis/chlorateel.html#anodes - the picks are the "gouging rods" before and after copper layer remotion ... is usually quite cheap :D )

some links:
http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...
http://www.wfvisser.dds.nl/EN/chlorate_EN.html#el_constructi...
http://yarchive.net/explosives/chlorate_mk.html
http://www.frogfot.com/synthesis/chloratecell1.html
http://www.vk2zay.net/article.php/64
http://www.vk2zay.net/article.php/86

[Editado em 4-1-2007 por Aqua_Fortis_100%]

[Editado em 4-1-2007 por Aqua_Fortis_100%]




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Lambda
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[*] posted on 4-1-2007 at 20:05
Cheap and free Electrodes


The best Carbon Electrodes I have found till now are those used by welders. They are Copper Foil wrapped (The Foil can easily be removed by just peeling it off) and have a round diameter of 1 cm and are 30 cm long. A small part of this Copper Foil may be left on the Electrode for good conduction between the Carbon Electrode/Clamp and Power source. They can be found in Welding supply Shops for about 2-3 Euro.:o

An other good source for huge Graphite Electrodes can be obtained from Tram and Train repair Workshops. I have obtained a few of these partly worn out Electrodes (Only the parts that contact the Copper Supply Rail were slightly imbedded by friction wear). They are about 4-5 cm square and 50-100 cm long, and clamped by a U-shaped Metal conductor Rail. Armed with a Crate of Beer, you will be able to save yourself a lot of hassle by making these Electrodes, and leaving a team of happy Train/Tram personnel behind.:D

Smaller Electrodes can be sulvaged from rundown cheap Zinc/Manganese Batteries (Not the high power Alkaline ones).

Happy hunting !

Regards,

Lambda.

@Aqua_Fortis_100%, you have simultaneously Edited your Post with the same info I have given here. We were thinking the same, and I did not read your added information before you had Edited your Post, neither were you able to read my Post before applying your changes. But what the Hell, we Chemists have the same Mind set anyway. That's why we like each other, and adhere to similar fields of interest. No Paranoid Bum Government Lobby will ever stop us and take this away.;)

[Edited on 5-1-2007 by Lambda]
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[*] posted on 16-8-2016 at 15:13


The following is an excerpt from the may 1911 issue of modern electrics, describing a method for producing your own DIY carbon battery electrodes:

The electro-chemical series is a com
bination of solid bodies, which are ar
ranged in such a manner that every one
of the mentioned bodies, becomes posi
tively electric with the one following di
rectly after it, when making contact with
same. If brought in contact with the
body immediately preceding it, it will
become negatively electric. This will be
clear by studying the following:
+ zinc, lead, tin, bismuth, antimony,
iron, copper, gold, platinum, graphite,
oxide of manganese—.
The E.M.F. which is generated by con
tacting any two of the bodies shown in
above chain, is greatest when the two
bodies are separated the widest. Thus
zinc and oxide of manganese will give the
greatest E.M.F.
It was soon found that the copper in
some of the existing batteries, when re
placed with carbon would give much bet
ter results. At first coke was used but it
could not be formed well nor could cylin
ders be made commercially. Coke is brit
tle and breaks easily when sawed.
Therefore the carbon as used today is
made artificially. It may be made as fol
lows:
I. Mix well 15 parts coke powder (or
graphite in crystal form), 8 parts lamp
black and 8 parts molasses. Press the
plastic mass in the desired form, dry in
the open air and heat red hot in an iron
container from which all air has been
drawn.

2. A piece of wood is burned slowly to
charcoal in a vacuum, by heating it in a
container as above. Soak the piece of
charcoal in molasses, or asphaltum of
paraffine. Heat to a red heat, soak again
and repeat this till the carbon so obtained
is hard and conducts electricity well.
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windham
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[*] posted on 16-8-2016 at 15:21


This same article can be seen in the original issue of modern electrics here (page 68):

https://play.google.com/store/books/details/Modern_Electrics...
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