making potassium (per) chlorate

[taiwanluthiers]

Where is Swede by the way? He seems to be the one with all the fancy lab equipment to make LD anodes.

[WSM]

Where is Swede by the way? He seems to be the one with all the fancy lab equipment to make LD anodes.

 

Swede lives where the Summers are HOT and unforgiving. I don't expect to hear from him for a while.

 

WSM

[taiwanluthiers]

Thailand? Summer everywhere else is a walk in the park compared to summer in Taiwan. It's not only HOT and unforgiving it's also extremely humid. Like Florida on steroids. I don't see anyone from Florida disappearing because of the heat...

 

Unless Swede is made of snow...

[WSM]

Thailand? Summer everywhere else is a walk in the park compared to summer in Taiwan. It's not only HOT and unforgiving it's also extremely humid. Like Florida on steroids. I don't see anyone from Florida disappearing because of the heat...

 

Unless Swede is made of snow...

 

Texas.

 

His workshop gets over 120 degrees F this time of year (and humid too, I bet!).

 

WSM

Edited June 21, 2013 by WSM

[taiwanluthiers]

I grew up in Texas... I'm guessing his workshop has no air conditioning?

[WSM]

I grew up in Texas... I'm guessing his workshop has no air conditioning?

 

That's right. You've got the picture.

 

WSM

[dangerousamateur]

Another question from me:

 

I'm loocking for some titanium material to make cathodes.

 

 

Ti seems to be the best - or is it not, did i overlook something?

 

 

Use Grade 1, 2, 3 or 4. The Grades containing Al are inclined to warp especially at high temperatures. There are reports of thin sheets of Grade one Ti becoming brittle and breaking soon after they are installed in a cell. Use sheets that are at least 1mm thick.

 

What's the grade I should look for, and how much current density is recommended for such cathodes?

 

I will use them together with laserreds MMO stuff.

[WSM]

Another question from me:

I'm loocking for some titanium material to make cathodes.

Ti seems to be the best - or is it not, did i overlook something?

What's the grade I should look for, and how much current density is recommended for such cathodes?

I will use them together with laserreds MMO stuff.

 

For the price and effect, titanium is the best choice.

 

The titanium I use is CP (commercially pure) grade. The recommendation to get it one millimeter or thicker is sound advice. Generally, the cathode plate or plates should be the same dimensions (length and width) as the anode.

 

The anodes determine the current demand of the cell and the cathodes are sort of just along for the ride (if sized to match the anode).

 

These suggestions are based on my experience, but your mileage may vary.

 

WSM

Edited June 24, 2013 by WSM

[dangerousamateur]

Thanks for your answer.

 

CP seems to be a collective term for grade 1 to 4.

 

Now if I had the choice between these 4 grades, which one should I take?

 

 

And can this material be machined with normal household tools, hacksaw and standard HSS drillbits?

[taiwanluthiers]

You can cut it with bimetal hacksaw blades... it's just slow though.

 

Avoid 6al4v titanium if you can... it doesn't stand up at all when used as anode connection. Maybe using it as a cathode somehow protect it.

[WSM]

1) Thanks for your answer.

2) CP seems to be a collective term for grade 1 to 4.

3) Now if I had the choice between these 4 grades, which one should I take?

4) And can this material be machined with normal household tools, hacksaw and standard HSS drillbits?

 

1) You're welcome.

2) Yes, that's true.

3) I believe grade 1 is the purest. If they cost the same, get grade 1. Otherwise, any of the CP grades will work fine in my experience.

4) Yes, it's about like mild steel in machinability. To bend it, heat to red hot and bend till it resists, heat to red hot again and continue. Repeat this process till your bend is complete and cool the piece in water. This process has worked well for me (I use a propane torch or an air/acetylene torch).

 

Good luck and have fun.

 

WSM

 

edit: Regarding machining, the HHS bits will get dull quickly. I should mention I use cobalt steel drill bits which I also use for various stainless steels. Both titanium and stainless steel heat up when machining, so the cobalt steel drill bits hold up better. For milling or lathe work, carbide or carbide tipped tools are recommended. Use plenty of cutting fluid, too.

Edited June 24, 2013 by WSM

[WSM]

You can cut it with bimetal hacksaw blades... it's just slow though.

Avoid 6al4v titanium if you can... it doesn't stand up at all when used as anode connection. Maybe using it as a cathode somehow protect it.

 

Smaller pieces (like MMO anode material) cut easily with a bi-metal hacksaw blade. Clamp the electrode in soft jaws so the MMO coating isn't compromised. I use a rubber sheet to protect it from the steel vice jaws when cutting some to size.

 

Yes, I believe so. It's called Cathodic Protection, but without power there's no protection!

 

WSM

[WSM]

Have a Happy and Safe Independence Day.

 

WSM

Edited July 4, 2013 by WSM

[LGM]

I'm considering getting an MMO anode that doesn't have a mounting shank, and I was wondering how other people have gone about attaching one. Would it be possible to solder a connection onto MMO material?

[taiwanluthiers]

I used a Titanium strap and little titanium "nails" made from the strap. Drill several small holes and bend the "nail" around it.

 

You have to use CP grade titanium... all Ti bolts out there are 6al4v that will dissolve immediately when used on an anode. That's the only solution I can think of in the absence of a spot welder.

[schroedinger]

or get some gr. 1/2 Bolts, they are out there to, a little bit more expensive then the normal ones, but not a lot

[WSM]

Would it be possible to solder a connection onto MMO material?

 

I don't know of any solder that would hold up to the environment of the cell. If you can find CP wire, try making rivits and fix the electrodes to the shanks with them.

 

The suggestions others here have made have merit also. See what works for you.

 

WSM

[schroedinger]

Look at svede's block, he shows there how to weld them

[WSM]

Look at svede's block, he shows there how to weld them

 

Right. That's the way I do them, but if you don't have a spot welder (and most don't), riveting might be the next best option.

 

I do have and use a spot welder, and feel it's money well spent. They can be had for about $160 from Harbor Freight Tool stores when they're on sale.

 

In fact, I also do the filled tubular CP titanium leads, held in modified PVDF compression fittings; the way Swede shows in his blogs. It's the best way anyone's ever shown to prevent salt creep, so far.

 

WSM

[Arthur]

IIRC Swede made his first spot welder and details will be in his Blog. Basically use a microwave oven transformer, rewind the secondary to supply about 2 - 2.5v at LOTS of amps using FAT wire. Use pure copper contact tips machined to about 1mm DIA as they press the Ti together they fuse the material and a few spots ate needed to carry the current.

[taiwanluthiers]

That isn't something anyone can do, nor are comfortable with.

 

The easiest way I can think of is to hacksaw little strips out of a CP Titanium plate and use them as "nails" to tie the anode to the strap. You can do this with tubular strap if necessary. CP wires aren't easy to find and 99% of the Ti bolts out there are not CP... I tried looking and it's like looking for a solid platinum bolt.

[WSM]

That isn't something anyone can do, nor are comfortable with.

The easiest way I can think of is to hacksaw little strips out of a CP Titanium plate and use them as "nails" to tie the anode to the strap. You can do this with tubular strap if necessary. CP wires aren't easy to find and 99% of the Ti bolts out there are not CP... I tried looking and it's like looking for a solid platinum bolt.

 

CP titanium wire can be found at a decent welding supply shop, as CP titanium welding rod. If it's not on the shelf, it can be ordered. It's not cheap, but certainly available.

 

For bolting them together, a large industrial supplier (McMaster Carr comes to mind) may also have CP titanium "all-thread" (threaded rod) available.

 

Along with that, one could make square nuts from square rod CP titanium (check eBay US listings) and properly sized taps to match the all-thread. Remember that CP titanium is similar to mild steel in machinability. I've found CP titanium bolts on eBay in the past but I passed on them at nearly $1 each (easy to do since I own a Harbor Freight spot welder).

 

All this depends on your motivation. It may not be easy, but it is possible.

 

WSM

Edited July 12, 2013 by WSM

[WSM]

I'm considering getting an MMO anode that doesn't have a mounting shank, and I was wondering how other people have gone about attaching one. Would it be possible to solder a connection onto MMO material?

 

There's one option not mentioned yet; if the MMO electrode is long enough, let it stick through the lid of the cell and clamp the power leads to it with stainless steel hardware. The hard part will be sealing the point where the electrode goes through the lid to prevent "salt creep" from affecting the electrical connections (a constant irritation to me till Swede shared with us the idea of round "shanks" sealed in a compatible compression fitting. Simply brilliant!).

 

When attaching the electrical connections, some have mentioned removing the MMO coating. This is not only unnessecessary but reduces the conductivity of the connection. The MMO coating is more conductive than the titanium under it, so removing it wastes power by increasing resistance.

 

Most beginners to electrochemistry buy or make electrodes and then try to get whatever power supply to feed it. Electrically, it makes more sense to get a power supply with an output of between 2-10 Volts DC and as many Amps as you can afford (the higher the Amperage output, usually the higher the cost) and tailor the size of the electrodes to match. Power supplies with variable outputs are even more useful but certainly more costly.

 

The sense in this is that the electrodes will only take as much current as they're sized for, you can't force feed them with more Amps. So if your anode is sized to demand 50 Amps and it's connected to a 100 Amp power supply, only 50 Amps will flow. The voltage is usually static and industry typically says 3.6 Volts is optimal, but in practice anything between 2.5 and 5.5 Volts seems to work fine for amateurs. Remember, current does the work in our cells and is the flow of electrons and Voltage is the "pressure" of the electrons.

 

The best electrical practice is to size the electrodes to demand no more than 80% of the power supply's output.

 

More about all this later...

 

WSM

Edited July 13, 2013 by WSM

[WSM]

"The best electrical practice is to size the electrodes to demand no more than 80% of the power supply's output."

 

 

To determine the current demand of an electrode, multiply the area in square centimeters by 0.3 Amps. If an anode has an area of 30 square centimeters on one side, that equals 9 Amps, or an average peak demand of 9 Amps from the power supply.

 

This holds true if one anode is used with one cathode. If, for example, you're using one expanded metal MMO anode with two flat sheet metal cathodes surrounding it, the total average peak demand will be 18 Amps.

 

If you measure the single side area of your anode in square inches, then to convert to square centimeters, multiply by 6.45, and then the current per square centimeter (0.3A).

 

Now say I have an anode that measures 2" x 3"and I plan to surround it with two cathodes of equal area? Multiply 2" x 3" = 6 square inches, single side

6 square inches x 2 = 12 square inches total area (both sides)

12 x 6.45 = 77.4 square centimeters

77.4 square centimeters times 0.3 Amps = 23.22 Amps

 

If 23.22 Amps is the peak average demand of your cell, then a 5Vdc 30 Amp power supply should serve your needs with no undue stress.

 

WSM

Edited July 13, 2013 by WSM

[pyrojig]

Gotta love the math of this science stuff!!! It is the lube that keep these projects running . . I would be the 1st to agree about sticking to the math on the electrodes. I can tell you from experience (bad) ,and burning up a couple Ps's do to way overloading them with excessively large electrodes .

Keep up the great work WSM!! We appreciate your dedication to this electo-chemistry !!! Swede will be thrilled to see you and others are keeping the tread alive.