[maxvortex]

Hi !

I have just two questions for a start :-)

1.) What is the difference between carbon rod from battery and carbon rod used for drawing ?

2.) How to make normal carbon electrically conductive ?

Max

[billnotgatez]

as best as I can tell from the internet

writing carbon in pencils is graphite and clay
carbon rods in batteries is made with graphite and a binder

that is my best guess
I could not find any thing for batteries directly

By the way from WIKI

There are several allotropes of carbon of which the best known are graphite, diamond, and amorphous carbon.

Maybe you can do some more research and find the definitive answer

[vmelkon]

Just to add to the above, when I heated pencil cores, there is some oily liquid that comes out and burns. The left over core is crumbly.

It is the same for carbon rod from batteries.

[curiouscat]

They probably use a binder. That might be the oily liquid.

[maxvortex]

Any link to this "oily binder " ?
I found this : http://students.chem.tue.nl/ifp40/Binders.htm and it looks as good way to start. Now we have to define how to make the binding process.

E.g. i have graphite powder and i want to make 5x5 cm graphite electrode.
Can this be done using oil binder and then again, will this hold...

[curiouscat]

Any link to this "oily binder " ?
I found this : http://students.chem.tue.nl/ifp40/Binders.htm and it looks as good way to start. Now we have to define how to make the binding process.

E.g. i have graphite powder and i want to make 5x5 cm graphite electrode.
Can this be done using oil binder and then again, will this hold...

Tar? Pitch? Some sort of resin?

[billnotgatez]

If you are making your own carbon electrode from graphite
Do you think crazy glue (super glue etc.) would work

[maxvortex]

Do you think crazy glue (super glue etc.) would work
***
No it will not. I tested with all kind of glue. non of them worked.
You will get conductive "line" but the outer surface is not conductive and you have no real bonds. I think that they are using some kind of different method to develop this..

[curiouscat]

My suspicion is when you use tar / pitch etc. and bake them at high temp. a lot of them may yield conductive by products. So you get binding with good conductive contact too.

[HCB]

Hello.  I'm not sure what your end product is to be but...

For the metal fabrication world there are Carbon rods used for arc-air gouging.  They are approximately 14 inches long and vary in diameter.  I have bought some which are 1/4 inch diameter and used them for electrolysis tinkering.  The rods I bought had a copper jacket which is easily removed by scoring with a knife and then peeling the copper jacket like pulling the skin off a fish...if you've ever skinned a fish like a catfish.  If not, it's like peeling a protective skin off a LCD screen.  Not hard to do.

Regardless, you can get Carbon rods which conduct electricity easily this way.  Readily available from a welding supply shop (I bought mine off-the-shelf from a local welding supply shop in my tiny (5k population, one-horse town).

However, I have no idea how they are formed: are they cored, pressed, or glued?  I do not know.  But they work well for electrolysis of water.  The formation process would matter to you if you require a specific size/shape, which I can not help with, unfortunately.

--HC

[maxvortex]

@HCB
The idea is to use this carbon electrodes in battery design.
One part of the electrode would be metal and the other carbon.
The main problem is that i need flat surface and i need quite big amount of this electrodes.
Electrode is used as current collector. Can you tell me the prize of your electrodes, where did you buy it ?


@others
I was trying to get/buy tar resin in my country but it's almost impossible because all is based on bitumen.
So i was thinking to make some of this tar on my own but it looks like it's not that simple project.
Accept to make something like: http://www.youtube.com/watch?v=zv0JMKbFsrQ

Any other idea or link where this can be bought ?

[curiouscat]

@others
I was trying to get/buy tar resin in my country but it's almost impossible because all is based on bitumen.
So i was thinking to make some of this tar on my own but it looks like it's not that simple project.

Oh what has the world come to!

What country is this where buying a bit of tar / pitch has become a problem? You really shouldn't have to make your own tar.

[maxvortex]

Almost any European country :-). You can get tar for boat repair but it's quite expensive on the other hand there is ecological issue so that's why they switch to bitumen. Before cca 5 years there was no problem but now bitumen is first choice.

Anyway, i made some pine tar like the guy in yt video.
The process is quite simple and you can easy improve the production.
I mixed carbon with this tar and am gonna let it dry in oven.
I will pass the results tomorrow.

[curiouscat]

Almost any European country :-). You can get tar for boat repair but it's quite expensive on the other hand there is ecological issue so that's why they switch to bitumen. Before cca 5 years there was no problem but now bitumen is first choice.

Bitumen should work fine too I think.

[408]

Can you tell me the prize of your electrodes, where did you buy it ?

I pay around 20$ for a box of at least 30 foot long 1/4 inch rods.  I cannot find the box but there is a lot in there, I think they are sold by weight as a similar sized box of the 1/8th rods weigh the same at the same price.  Go to a welding store and ask for graphite gouging rods.