Pressing graphite, PbO2, MnO2 and other powders into rods - is it possible?
I was trying to find out if it is possible to press graphite dust into a cylindrical rod or even cube-ish shape (flat edges). I was thinking of
using something like a cast iron pipe (size dependent upon hydraulic press strength), filled with powder and then pressed with a steel rod/bolt or
drill bit shaft (more choice in sizes and hardened) where the other side is either closed with a pipe cap, a plug like that used as the press shaft,
etc. Once pressed, remove one end and then press the graphite rod out.
I looked at the mechanics and physics of presses and it seems that there is relatively little lateral pressure on the side of the pipe when pressing
something like this. There is some, but I found that using the press to push the compressed material out is much more than adequate.
I'm wondering if using pressure from a 20 - 40 ton press would be enough to keep the material together. I've figured out how much pressure a 20 ton
press would equal if for different size pipes.
Percentage of one square inch
area of 1/2" pipe = 3.14*(.5*.5)^2 = .19625
area of 3/4" pipe = 3.14*(.5*.75)^2 = .4416
area of 1" pipe = 3.14*(.5*1)^2 = .785
area of 1.5" pipe = 3.14*(.5*1.5)^2 = 1.766
area of 2" pipe = 3.14*(.5*2)^2 = 3.142
Press rating is usually at PSI - pounds per square inch, so the above are a percentage of 1 sq inch - so the first 3 would have a higher pressure than
the rated press tonnage and the last two would be lower
20 ton press (40,000 PSI)
.5" pipe = 40,000/.19625 = 203,821 lbs per rod
.75" pipe = 40,000/.4416 = 90,580 lbs per rod
1" pipe = 40,000/.785 = 50,955 lbs per rod
1.5" pipe = 40,000/1.766 = 22,650 lbs per rod
2" pipe = 40,000/ 3.142 = 12,739 lbs per rod
I know a lot of people look at making electrodes and there are some complicated methods but I was thinking that this might be easier if it would work.
Batteries (alkaline) are pressed and they are REALLY hard so I think MnO2 might work.
I was thinking that an arrangement like this might be useful in calcining or heating to high temps and keeping O2 out. Adding heat might help with
the press process to some degree as long as it doesn't weaken the pipe too much. Using a torch, burner, induction coil, etc would be options.
I'm also wondering if adding a binder might help or be needed, especially if it can be activated with pressure or heat!.
I'm trying to think of other compounds or elements which might be able to be (useful) if pressed into rods like this.
For those who don't have access to a shop machine press a car jack can work but it usually isn't near the tonnage. Another option is a hydraulic log
splitter and those are common above 20 ton, so that could be useful.
*note, square/rectangle ones can be done as well, but they are difficult and may require welding, machining, tapping screw holes, etc.
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