05-03-2002
Stainless steel and the Joe cell.
Introduction.
I am including more information on the stainless cylinders and their preparation and treatment.
My aim is twofold, firstly to clear up some of misconceptions that seem to have entered the arena.
Secondly to add new material that may further help the experimenter.
Stainless steel.
There is nothing magic about stainless steel, or the reason that we use it in the cell.
We use it because it is reasonably inert to the electrolysing process and far cheaper than titanium, gold or platinum, the last mentioned being the perfect choice but simply too costly even for Universities ( in the quantity required ).
So as we are making a cost compromise, we must be prepared for problems that result from not using the optimum material. And the stainless does have many problems.
Types.
There are many types of stainless steel and they fall under three broad categories:
1. Austenitic.
These contain chromium and nickel as the main percentage of the alloy.
Type 302, 304 and 316 are typical examples.
2. Ferritic.
These contain mainly chromium and ferrite.
Type 430 is a typical example.
3. Martensitic.
These are low carbon steels containing mainly iron and chromium.
Type 410 is a typical example.
As we are only interested in ' non magnetic 'stainless steel, we are interested in the austenitic or type 3xx variety and more specifically type 304, 316 or 316L.
Of the three mentioned types, 316L has superior corrosion resistance to chemicals and is the most common type used by Joe cell experimenters.
As said previously, I use it as well, but I am quite partial to the cheaper 304 ( food grade )
Quality.
I could write volumes here, but basically you get what you pay for.
If the steel is not wrapped in a plastic sleeve, does not have regular type identification numbers on it, shows a longitudinal discoloured weld seam, is thicker at the weld seam and is out of round, do I really have to tell you that you have got an inferior ( and thus cheaper ) length and that you should not even bother taking it out of the rack?
Now the above are ' first impression ' things that you can do with your hands still in your pocket.
If your steel does not have of the above traits, it is time for the trusty rare earth magnet. I have described the test procedure before, so I will not elaborate.
For the lucky ( read with money ), seamless steel that is extruded is the way to go and you increase your chances of success by quite a large margin.
If you were wondering, no, I cannot afford it and I use what I can get.
Okay you say, my steel looks great, tests great, do I have a piece for the construction of the perfect cell?
Sadly no, for there are yet many hurdles to jump. Read on.
I have mentioned over and over that the Joe cell is the most deceptive device of all, it looks so simple to make, it has so few parts and yet less than a dozen ( known experimenters ) can make it fly.
I would love a dollar for all the hours of frustration that experimenters around the world have poured into the cell, I would have to be a multi-millionaire and quite a few thousand hours of that time would have to be my contribution.
If only the people who ' knew 'would share, now what a wonderful world that would be. < sigh >
The ' right ' stainless steel.
Additional to the above type and quality of the stainless, we enter into the world of pseudo science or at least science that is not taught in Universities and such like.
Let me give you a few examples:
1. A person that could not get his cell going took it to Joe. Joe simply moved the position of the positive connection to the cell on outer case and it commenced working.
2. Another person took a non working cell to Joe. Joe told this individual that the two inner cylinders were " upside down ".
3. Another non working cell was taken to Joe. Joe drilled the minutest hole in a critical area and the cell sprung to life.
4. A person was walking down Joe's drive-way with his $6,000 dollar purchase of the ' right ' steel. Before he got to Joe, Joe told him it was ' crap ' and to take it back.
5. To get the ' right ' steel keg, Joe chose out of 200 beer kegs and even now only has one keg that will start up in exactly the same mode each time.
6. When your cell does not work, Joe recommends the ' flashing ' of the cylinders to set up the right
' field '.
The above examples are some that come quickly to mind, there are many others.
So dear reader, you have read the above, what do you make of it?
I will tell you what I make of it and it is all bad news for a ' quick and easy ' project.
a. There are obviously complex atomic and sub-atomic characteristics that are involved.
Additionally there are magnetic, electric and aetheric interactions at a very subtle level.
b. There is some form of tuning involved that is not measurable with conventional scientific methods.
c. Some people can ' see ' and thus make or correct components by ' intuition ' or ' gut feeling '.
Summing up a. b. and c., I read that scientific methods alone will not make a cell work nor be able to explain the operation. But then you knew that. <g>
Back to the stainless, what can you do to at least enhance your cells ability to ' do ' something?
Suggestions.
1. It goes without saying that you should get what has worked for others. Definitely 304, 316 and 316L has and is working for experimenters.
2. Make sure that your chosen cell passes the tests as mentioned previously and above.
3. If you cut the steel, use a low temperature process and a cutting method that does not inbed foreign material in the cut. Read my previous notes on the subject.
4. Make sure that the length of your inner tubes are close to the same length with parallel cuts top and bottom. Very easy to test at the machine shop before you pay your good money, simply place on a flat surface and hold a metal ruler on edge across the top. This little test tells all.
If your cylinder set has just come of the lathe, there are no excuses for sloppy work. If you have made a set at home, please realise that the length has to be reasonably the same, in actuality only the top surface of the cylinder pack had to be dead level, the odd length can ' hang ' out the bottom.
A little trick, if the one inch tube is higher than the rest, it can ' see ' over the top of the others and your cell is dead! Far better to lower the central tube a smidgin and thus it will be ' blind '.
The above is easily observed by filling the cell to meniscus level and observing the bubble pattern.
5. If you have to polish the tubes, be very careful! The polishing lines must not run at an angle to the circumference of the tube. I have mentioned this before as it is hard to do inside the two inch.
What I have not explained is exactly how to ' clean' the stainless tubes before using.
This now follows:
Passivation.
This is a generic term used to describe the process of removing free iron from the surface of the stainless. If not done, the surface may exhibit the ' rust spots ' that most builders complain about.
The process should remove the surface contamination without significantly affecting the stainless steel itself.
It is the addition of the chromium that makes the steel rust resistant by combining with the oxygen to form a very thin and invisible layer of chromium oxide.
This is called the passive film.
So, as you busily polish your works of art, you are also removing this thin chromium film and exposing the iron to the air and thus you have rust, the brown spots that we are all familiar with.
No, don't slash your wrists, the cure is very simple.
Methods of passivation.
The commercial method involves the submerging of the steel in a solution of nitric acid ( 20-25% by volume ) and sodium bicarbonate ( 2-3% by weight ) and 35% of water.
The steel is submerged for 20 to 30 minutes and the nitric acid dissolves the iron and restores the original corrosion resistant surface.
Dear reader, nitric acid is not very friendly, expensive and not easy to dispose of. Leave this method to the professionals.
For home use I would suggest citric acid that is easy to get and is safe and easy to use. A 4-10% by weight solution in water works just fine to passivate, clean and brighten just about any stainless steel.
The time is about the same as for nitric acid and as you should not be in a hurry, 30 minutes is fine.
Rinse in NON tap water ( your favourite mix ) and they are ready for assembly.
Electropolishing.
As you are by now the proud owner of a power supply, various containers and other equipment as used by those ' familiar with the art <g> ', you may be interested to try and do your own electropolishing.
By using oxalic acid ( your wife may have some for dying cloth ) or by using phosphoric acid ( if you have made Go-Juice ) as an electrolyte, and a bar of copper as your cathode ( negative ) you are ready to go.
Your stainless steel has positive lead clipped to it and the copper bar or rod is your negative. Put them in a plastic bucket or similar and adjust the concentration of the electrolyte until you get decent action with your power supply of battery.
Bingo! all the cruddy heat tint and similar are gone forever.
Conclusion.
Even after purchasing you super expensive bit of seamless stainless, lovingly prepared by the vestigial virgins in the Black Forrest, it still may not work.
This is due to the molecular alignments within the metal and the interaction with the subtle fields in the near vicinity of the cell.
I would suggest that you do all the previously mentioned operations and then ' flash ' each tube before assembling the cell. If a certain tube does not produce bubbles from both surfaces or does not seem to take part in the action, try turning it end for and/or rotating a 1/4 of a turn at a time.
When you have your tubes perfectly aligned mark this position with some form of indelible mark. A tiny pin punch mark on the bottom cut edge is fine.
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