making potassium (per) chlorate

[WSM]

This is my first post so be gentle with me

I apologize if this has been previously discussed, but I'm wondering what the recommended cathode thickness is for a chlorate cell. I'm planning to run with two cathodes sandwiching a 1" x 10" mmo anode (from laserred) at approximately 25 - 30 amps. I've found some (I think) decently priced grade two titanium sheets on ebay that are .040" and .041" thick. Would that be sufficient?

Thanks,

Kev

 

I forgot to ask where you live? If you're in the US, we can offer different suggestions depending on which part of the country you're in.

 

Regarding "decently priced" titanium, it depends on how much they're asking plus any shipping fees and/or taxes that may be attached. If you throw out a number, we can respond to those numbers.

 

WSM

[Kevin]

Thanks WSM, I've read a fair bit on this forum and I'm excited join the community!

 

Well if it worked for Swede, then I'm confident in it

 

I'll be using a computer PSU that's rated for 32A. I was planning to space the electrodes appropriately to get my desired current, but would you recommend keep current density near its maximum instead?

 

I did get five pieces so I would definitely consider cutting one for my first MMO run (previous runs used graphite rods and stainless steel mesh, but decanting is a real pain).

 

I really want my cell to be transparent so I'll be using glass. If I cut the electrodes shorter I could use a 1 imperial gallon glass jar that I have kicking around, but for 10" I'd have to pick up something new.

 

Unfortunately for this hobby, I live in Canada. The price is 20 USD for four pieces measuring .040" x 6" x 10" C.P. gr.2, with additional cuts costing $7 more. Shipping is my problem as it'll be around $45, though I could double my order and to my understanding it would only add a little to the shipping .

 

Thanks again for the help,

 

Kevin

[WSM]

Thanks WSM, I've read a fair bit on this forum and I'm excited join the community!

Well if it worked for Swede, then I'm confident in it

I'll be using a computer PSU that's rated for 32A. I was planning to space the electrodes appropriately to get my desired current, but would you recommend keep current density near its maximum instead?

I did get five pieces so I would definitely consider cutting one for my first MMO run (previous runs used graphite rods and stainless steel mesh, but decanting is a real pain).

I really want my cell to be transparent so I'll be using glass. If I cut the electrodes shorter I could use a 1 imperial gallon glass jar that I have kicking around, but for 10" I'd have to pick up something new.

Unfortunately for this hobby, I live in Canada. The price is 20 USD for four pieces measuring .040" x 6" x 10" C.P. gr.2, with additional cuts costing $7 more. Shipping is my problem as it'll be around $45, though I could double my order and to my understanding it would only add a little to the shipping .

Thanks again for the help,

Kevin

 

Hi Kevin,

 

The best electrical practices say the optimal load is 80% of the maximum output (or 25.6 Amps from a 32 Amp supply). That way the power supply should operate without overloading or overheating for a long run.

 

The CP titanium isn't as hard as alloyed Ti (more like mild steel in hardness) and can be cut with a hack saw. Two 1" x 6" cathodes shouldn't be too tough to cut and will probably work fine with a 1" x 5" anode, even with fairly close spacing. Why is the shipping so high (or are import duties involved)? Also, I wonder if CP titanium sheet metal is available in Canada? I would think so.

 

WSM

Edited August 22, 2015 by WSM

[Arthur]

"I really want my cell to be transparent so I'll be using glass. "

 

My guesses based on reports here are that glass cells MAY erode at high pH and that the eroded material may passivate some electrodes. SO I'd highly recommend pH control in a glass cell. pH control assists with current efficiency AND seems to assist electrode life. BUT it's a pain because the solution eats pH electrodes and bleaches pH paper.

[WSM]

"I really want my cell to be transparent so I'll be using glass. "

 

My guesses based on reports here are that glass cells MAY erode at high pH and that the eroded material may passivate some electrodes. SO I'd highly recommend pH control in a glass cell. pH control assists with current efficiency AND seems to assist electrode life. BUT it's a pain because the solution eats pH electrodes and bleaches pH paper.

 

True, glass may or may not be effected by high alkalinity in the cell depending on the conditions present. If it does etch the glass, it's likely to cause problems for the electrodes.

 

As Arthur mentions, one way to solve the issue is to add pH control, which may be as simple or complex as the operator cares to make it or can afford. My best recommendation is to be sure to add the hydrochloric acid (pool acid) slowly and well below the surface of the electrolyte surface, to help eliminate the release of toxic and dangerous chlorine gas. This may be accomplished by using a compatible plastic tube, extending deeply into the cell, possibly with cross-holes drilled into the sides at the bottom 2" of the tube to help the acid slowly diffuse into the mother liquor and do it's work in a controlled manner.

 

I also lean toward diluting the HCl (chemical formula for hydrochloric acid) with distilled water, to more easily control the amount of acid being added. Adding more water is another positive aspect of using dilute acid, since the running system basically consumes water, but modifies the salt.

 

The strong bleaching characteristics of the electrolyte is a problem, but with careful observation of the pH paper immediately as it touches the liquid, one can get a short glimpse of the indicating color before it bleaches out, and have an idea of the actual pH (or at least close, which is good enough in most cases).

 

Challenges are opportunities, not problems. Keep a positive outlook and enjoy the process. It's fun!

 

WSM

[WSM]

Hi Kevin,

 

I forgot to ask, are you using potassium chloride or sodium chloride for your electrolyte?

 

WSM

 

Edit: And which Province?

Edited August 22, 2015 by WSM

[taiwanluthiers]

While CP titanium can be cut with a hacksaw, it's very slow going. You will want to use bimetal hacksaw blades. It's less to do with the hardness of the titanium than the fact that it conducts heat poorly so the heat tends to dull blades fast. In frustration I cut it with a bandsaw using wood blades, ruined it in a flash (but it was going dull so it was going to get thrown out anyways)

[WSM]

While CP titanium can be cut with a hacksaw, it's very slow going. You will want to use bimetal hacksaw blades. It's less to do with the hardness of the titanium than the fact that it conducts heat poorly so the heat tends to dull blades fast. In frustration I cut it with a bandsaw using wood blades, ruined it in a flash (but it was going dull so it was going to get thrown out anyways)

 

Yes, I always get bi-metal hacksaw blades. They last much longer than cheaper blades.

 

WSM

[schroedinger]

A dremel tool or angle grinder on the big ones also does a good job. Edited August 23, 2015 by schroedinger

[Kevin]

I picked up a couple bi-metal hacksaw blades today; I went with 32 TPI.

 

I don't think any duty fees are in there, so I'm not entirely sure. It guess that's the price for USPS priority mail to Canada? I emailed/ called no less that six metal suppliers/ fabricators and the only ones where it was a possibility gave me a quote of almost $400 CAN for ten pieces of grade two measuring .040" x 1" x 10" and a 24" piece of tubing with an OD of 1/2"! They told me that that'd be shipped out of the states which was a decent portion of the price (I can't remember the entire price breakdown).

 

 

My guesses based on reports here are that glass cells MAY erode at high pH and that the eroded material may passivate some electrodes. SO I'd highly recommend pH control in a glass cell. pH control assists with current efficiency AND seems to assist electrode life. BUT it's a pain because the solution eats pH electrodes and bleaches pH paper.

 

Yeah I was thinking of using the method of having a timer controlling a solenoid valve. I think I'll try taking some samples from my cell and boiling them before using my pH meter to fine tune my acid additions. I picked up a 4L jug of muriatic acid which I'll dilute prior to use.

 

 

Hi Kevin,

 

I forgot to ask, are you using potassium chloride or sodium chloride for your electrolyte?

 

WSM

 

Edit: And which Province?

 

I have a 20 kg bag of potassium chloride water softener.

 

Kevin

Edited August 23, 2015 by Kevin

[taiwanluthiers]

I don't know how but shipping to and from Canada costs a lot more. Even sea shipping from Canada to Taiwan (I ordered from Lee Valley in the past) costs as much as priority international shipping for the same weight, except sea mail took 10x longer than priority international.

 

I found my piece of titanium from ebay, some Russian guy was selling them.

 

When you cut the titanium, save the shavings, it makes great sparks mixed into any composition.

[WSM]

I picked up a couple bi-metal hacksaw blades today; I went with 32 TPI.

I don't think any duty fees are in there, so I'm not entirely sure. It guess that's the price for USPS priority mail to Canada? I emailed/ called no less that six metal suppliers/ fabricators and the only ones where it was a possibility gave me a quote of almost $400 CAN for ten pieces of grade two measuring .040" x 1" x 10" and a 24" piece of tubing with an OD of 1/2"! They told me that that'd be shipped out of the states which was a decent portion of the price (I can't remember the entire price breakdown).

Yeah I was thinking of using the method of having a timer controlling a solenoid valve. I think I'll try taking some samples from my cell and boiling them before using my pH meter to fine tune my acid additions. I picked up a 4L jug of muriatic acid which I'll dilute prior to use.

I have a 20 kg bag of potassium chloride water softener.

Kevin

 

32 TPI should work (it's the best size for thin walled tubing) but will be slow going for heavy pieces.

 

Those shipping quotes seem excessive. Do you live close enough to the US border that you could pick things up in the US?

 

Why boil samples? Can you try the pH paper method? It works for me and I don't have to boil any electrolyte.

 

How much did the KCl water softener salt cost?

 

Sorry for all the questions, but I'm trying to get a feel for the whole situation there.

 

WSM

[WSM]

I don't know how but shipping to and from Canada costs a lot more. Even sea shipping from Canada to Taiwan (I ordered from Lee Valley in the past) costs as much as priority international shipping for the same weight, except sea mail took 10x longer than priority international.

I found my piece of titanium from ebay, some Russian guy was selling them.

When you cut the titanium, save the shavings, it makes great sparks mixed into any composition.

 

I bought several pieces of CP titanium tubing (Russian aerospace surplus) from a guy in Latvia for a decent price and shipping was international flat rate and fairly low cost. He used a light weight tube with plastic plugs and stabilized the tubing with plastic foam blocks, cut to fit. I got 6mm OD and 8mm OD tubing, both with about 1mm walls.

 

I use them for leads to the electrodes. I spot weld the electrodes and leads together, then fill the leads with lead-free solder (to increase conductivity and decrease heating). I also hold the leads modified Kynar (PVDF plastic) compression fittings, in a PVC plate, used for a cell lid. All this makes for a tight fit that doesn't allow the salt creep which will eat your electrical connections.

 

Kevin, how do you plan to connect your power from the supply?

 

WSM

[WSM]

A dremel tool or angle grinder on the big ones also does a good job.

 

I suppose so, but it seems it would waste a lot of material (or cut-off blades, unless your hands are steadier than mine).

 

WSM

[Kevin]

 

When you cut the titanium, save the shavings, it makes great sparks mixed into any composition.

 

Will do!

 

 

32 TPI should work (it's the best size for thin walled tubing) but will be slow going for heavy pieces.

 

Those shipping quotes seem excessive. Do you live close enough to the US border that you could pick things up in the US?

 

Why boil samples? Can you try the pH paper method? It works for me and I don't have to boil any electrolyte.

 

How much did the KCl water softener salt cost?

 

Sorry for all the questions, but I'm trying to get a feel for the whole situation there.

 

WSM

 

I would prefer to get it direct, but going across the border could work.

 

I had it in my mind that an actual meter would be more accurate, but if pH paper works well enough I'll give it a try. (Now what do I do with my brand new pen meter... )

 

The KCl cost around $30 CAN

 

No worries; ask away! I just didn't want to fill this thread/ forum with newbie posts that have been said a hundred times.

 

 

I got 6mm OD and 8mm OD tubing, both with about 1mm walls.

 

 

How much current can those respective ODs carry when filled? Is there a rough formula? I've been looking for some tubing as well because I was figuring I'd have a go at the method you mentioned. I just don't know how big I need my tubing to be. I have, in progress, a MOT spot welder that I'm planning to use for my electrodes and I'll order some compression fittings once I have tubing diameters figured out. My plan is to have a sealed lid to virtually eliminate any gas leaks and salt creep. The cell will be run in a shed with the vent tube going outside.

 

I'll try to post a picture of my proof of concept lid attempt:

 

 

I got this idea from over on Science Madness; I think it was Xenoid's concept.

Edited August 23, 2015 by Kevin

[WSM]

 

I would prefer to get it direct, but going across the border could work.

 

I had it in my mind that an actual meter would be more accurate, but if pH paper works well enough I'll give it a try. (Now what do I do with my brand new pen meter... )

 

The KCl cost around $30 CAN

 

No worries; ask away! I just didn't want to fill this thread/ forum with newbie posts that have been said a hundred times.

 

How much current can those respective ODs carry when filled? Is there a rough formula? I've been looking for some tubing as well because I was figuring I'd have a go at the method you mentioned. I just don't know how big I need my tubing to be. I have, in progress, a MOT spot welder that I'm planning to use for my electrodes and I'll order some compression fittings once I have tubing diameters figured out. My plan is to have a sealed lid to virtually eliminate any gas leaks and salt creep. The cell will be run in a shed with the vent tube going outside.

 

I'll try to post a picture of my proof of concept lid attempt:

I got this idea from over on Science Madness; I think it was Xenoid's concept.

 

If you have a friend in the US receive orders for you and you pick them up from them on your US visits, the savings could allow you to buy more materials rather than waste the funds on outrageous shipping costs.

 

The pH doesn't have to have pinpoint accuracy and "close enough" really does work (just be sure to keep the pH well above 6.0 so chlorine gas isn't generated) according to Swede. The pH pen comes in real handy when you're purifying sodium perchlorate and potassium perchlorate, so don't get rid of it.

 

I truly don't know how much current they can handle, but I guess at it, based on the cross section of the solid filled titanium tube compared to the relative conductivity of copper and titanium rods.

 

Once you know the OD of your CP titanium tubing, you can order PVDF compression fittings to match. Even then, you'll need to modify the fittings so the tubing will slide through rather than stop in the fitting, by drilling though them with the appropriate sized drill. I find the 6mm OD tubing fits well in 1/4" compression fittings and the 8mm OD tubing in 5/16" compression fittings. I also have 3/8", 1/2" and 3/4" OD CP titanium tubing lengths.

 

I like the lids you made. What material is the lid and the O-ring?

 

WSM

Edited August 23, 2015 by WSM

[Kevin]

Sadly I don't have any close friends from down south. And I'm guessing metal supply companies probably always cost a lot when they're cutting everything fresh..

 

Yeah I'll definitely keep it! Perchlorates... that's another whole can of worms! But I'm open to working my way up there.

 

Okay, I was thinking 3/8" for 30A and 1/2" for 60A.

 

These darn tubes and plates have really been slowing me down!

 

 

I find the 6mm OD tubing fits well in 1/4" compression fittings and the 8mm OD tubing in 5/16" compression fittings. I also have 3/8", 1/2" and 3/4" OD CP titanium tubing lengths.

 

Thanks for that; I've wondered how well metric tubing and imperial fittings worked together.

 

Thanks! I made them out of materials I had kicking around. I think the plastic is HDPE puck board, and I think the O-ring is from an old oil filter- I wish I knew more details to give you!

 

Any suggestions for straightening out MMO electrodes? Mine have some rounded corners probably from being cut.

Or is that no cause for concern?

Edited August 24, 2015 by Kevin

[WSM]

Any suggestions for straightening out MMO electrodes? Mine have some rounded corners probably from being cut.

Or is that no cause for concern?

 

It's too difficult to remove the edge bends without ruining the MMO coating. Several years ago, laserred sold larger pieces of MMO mesh, typically 30" long by 4" wide (3" with 1" more at a 90^o angle to the rest). Occasionally, he also had 30" long by 6.75" wide MMO mesh.

 

He discovered he could make a LOT more money by cutting it up and selling smaller bits, so he did, and that's the situation we have now. The deal isn't as good as it was, but he's still the lowest cost MMO out there. We believe it's industrial surplus, but it works great for our purposes, usually.

 

I'd use it as is and not worry about the bend (or you could cut off the bent portion if it bothers you).

 

WSM

[pyrojig]

I imagine it would only pose a problem if he was trying to closely space the electrodes . I would just use as is. I personally found that the dremble and a cutoff wheel worked wonders. I too used a wiss sheet metal cutter , it worked ,but was more destructive to the coating where the cut was . Hard to beat the clean cut from a cutoff wheel . Just my two cents.

Wsm and a few others have been trying tight tolerance boxed electrodes , and that is why I made the statement above . Ive been at electrolysis for several years , and still learning tons of new stuff. I still wonder about electrode spacing and the effect it has on the CE of the sys. .

[WSM]

I imagine it would only pose a problem if he was trying to closely space the electrodes . I would just use as is. I personally found that the dremble and a cutoff wheel worked wonders. I too used a wiss sheet metal cutter , it worked ,but was more destructive to the coating where the cut was . Hard to beat the clean cut from a cutoff wheel . Just my two cents.

Wsm and a few others have been trying tight tolerance boxed electrodes , and that is why I made the statement above . Ive been at electrolysis for several years , and still learning tons of new stuff. I still wonder about electrode spacing and the effect it has on the CE of the sys. .

 

As to the spacing of the electrodes in a chlorate cell, the jury is still out. Amateurs have been all over the map regarding spacing, and it seems that if everything else is okay, the spacing hardly matters. There are many other factors that appear to be more important to the efficiency and success of amateur cell operation.

 

I'm sure on some level spacing will play a critical role, but for our systems the success of making usable oxidizers at all, makes all minor inefficiencies trivial to us. The profit driven and competitive nature of industry forces them to struggle for the highest output at the lowest cost, so minor inefficiencies are huge stumbling blocks to their goals. Amateurs can overlook these problems and enjoy their successes in making usable oxidizers.

 

WSM

Edited August 25, 2015 by WSM

[WSM]

To continue my articles on homegrown oxidizers, my current efforts involve:

• testing my potassium perchlorate samples for sodium contamination
• further purification if any is found
• when it's pure, convert the remaining sodium perchlorate to potassium perchlorate
• start sodium chlorate cell experiments
• develop and refine the sodium chlorate process for perchlorate cell feed stock
• run sodium perchlorate cells with home made sodium chlorate
• test the longevity and durability of platinum and LD anodes in practice

I have a lot to do and limited time to accomplish it if I'm going to keep up with the publication schedule for the PGI bulletin. I also need to hone my skills in blogging to post these articles here for everyone to use and enjoy.

 

WSM

Edited August 25, 2015 by WSM

[Kevin]

Laserred had some larger pieces available (3x10 and 6x10), but the price per square inch was cheapest with the 1x10. It wasn't until after I bought mine that I realized all the additional stems, fittings and spot welding I would need.. All right, I'll try it as it is. I guess the worst case scenario is that if current density is too high on the bent part the MMO will wear out and the titanium will passivate beneath.

 

Pyrojig, is there a specific kind of cutoff wheel that you've found to work best?

 

Ive been at electrolysis for several years , and still learning tons of new stuff.

 

It seems like the learning never stops! All I wanted to do was make some saltpeter and sugar smoke flares, and here I find myself knee deep in electrochemistry.

 

I got another quote recently and am looking for some feedback, all pieces are .041" thick: 6 pieces cut 6" x 10", 14 pieces cut 1" x 10", and 4 pieces cut .5" x 10". They'd cut these pieces from two larger pieces measuring 8" x 40" and send the remaining material. I calculated the pieces they'd use to be 640"² and my cut pieces to be 520"², leaving me with 120"² uncut. The price for materials and shearing is $77.04 US and the shipping is $57.95 US.

 

Kevin

[pyrojig]

Keven I have found that the standard drembel cut-off wheels work perfect. they are thin wafers . If your not careful and rush it or get it in a bind , they tend to break . I just bough a pack of them for reason./

I too got into electrochemistry knee deep as well, it is a whole new field of learning , and as said, never ends. It is more the quest ,than the end result that fuels the fire/passion to pursue learning . I was after a cheap oxidizer to fuel smokes / star comps and shooting targets.

[Sparx88]

While CP titanium can be cut with a hacksaw, it's very slow going. You will want to use bimetal hacksaw blades. It's less to do with the hardness of the titanium than the fact that it conducts heat poorly so the heat tends to dull blades fast. In frustration I cut it with a bandsaw using wood blades, ruined it in a flash (but it was going dull so it was going to get thrown out anyways)

 

 

I don't have any experience making perc, but from my experience with sawzall blades and band saw blades cutting things like ti, Hoppe's honing oil, Rem oil, and/or Break Free dripped while cutting improves the process for faster cutting, less heat and slows the rate of the blade becoming dull. Out of the 3, Break Free works best. Then after those pure 70 weight silicone oil helps great. You can get the silicone oil from a hobby store sold as shock oil.

[WSM]

Well, I took the plunge.

 

I've been salivating over some larger power supplies on eBay for some time now. The one that caught my eye is a Sorensen 0-7.5 Vdc, 0-140 A, rack mount unit. The typical asking price for these things is $450-$600 (ouch!).

 

One company (a salvage seller), had nine of them and said about $500+ shipping or best offer, so I figured, "What the heck?" and offered $150 (plus shipping at $38.28, or 188.28 total). This morning I woke up to a message saying that I got it (they accepted my offer)! Uh oh, they called my bluff ; now what do I do?!!

 

Being an upstanding fellow, I commit to buy it and pull out the magic plastic... Done (now I have six months to pay for it before my wife figures out my folly).

 

When it arrives I'll put it through it's paces and see if it's the excellent score I hope it is. I'll let you know...

 

WSM

Edited September 17, 2015 by WSM