Swede Posted July 29, 2012 Posted July 29, 2012 Nice find on the PVDF tube. If I wasn't mechanically stirring, that's be ideal. The only problem I can think of would be mounting it. PVDF doesn't solvent weld, so some method would have to be found to mechanically secure it. That's some good welding work, WSM. Welding heavier titanium can be a PITA, and past a certain thickness, spot welding has a hard time making a good joint. Remember with spot welding, the entire thickness would need to be brought up to heat, and that's tough to do with these light welders. My first spot welder was a homemade job, combining a rewound transformer, a foot pedal, and an industrial timer. I can set the timer for the weld duration, anything from 0.1 seconds on up, tap the pedal, and it energizes for that time period. That unit was used to spot weld very light stainless sheet for model gas turbines. When I tried to use it on heavier Ti, it choked, so I replaced the transformer with that exact Harbor Freight unit you described. Mounted the whole thing on a giant aluminum base which gets bolted to a benchtop. The timer makes for precise, even welds. http://www.5bears.com/perc/tc115.jpg For heavier stuff, it's hard to beat TIG. While I can't do aerspace-grade Ti welds, it's easy to make ugly welds that are mechanically sound, and conduct. The TIG did these ugly welds: http://www.5bears.com/perc/tc057.jpg TIG isn't something you buy for hobby electrolysis - they are pretty expensive, but if someone needs some heavy Ti welded up, you could probably walk into any welding shop (bring in some CP Ti wire they can use for fill, as many shops don't normally weld Ti) and have them do it. The cost would be reasonable. One last thought - I was wandering through our local "Container Store" and admiring their large stainless trash cans. Has anyone tried a big cell made out of stainless steel? If the container is tied to the cathode, it should be cathodically protected and not degrade. Or, the entire container could be the cathode.
pyrojig Posted July 29, 2012 Posted July 29, 2012 You talking about 55gal metal cans? That would be a BIG cell.\ Im sure your speaking of the smaller 13gal or tad larger cans.... Seems like the container would be protected , but two probs would exist. The original welds of the can would not be sufficient , and the top of the can would be very susceptible to rusting from the mist that arises. You then have to insulate the leads into the cell, but that is no big deal with Kynar fittings. Heat may be another thing gained from the metal container. (which in most instances would be a good thing). Viton or alike gaskets will have to seal the lid as well. But the lack of Ti cathodes may be kinda nice . In this instance you could roll a large sheet of Anode around a pvc former and spotweld it into a circular cage to get it closer to the cathode wall.
bikemaster Posted July 29, 2012 Posted July 29, 2012 Ytmachx did it some time ago : It seem to work great, but he use a pipe with a large thickness, compare to the thickness of the trash can wall. First we need to know the quality of the stainless steel they use to make the trash can. If a magnet doesn't stick to it, it's a really good news! But these type of trash can are usually made of low quality SS, so test need to be done. It feel really good to see that your back Swede! I had to stop all my testing on chlorate cell because I was going to university , and I can't bring all my chemical in my appartement... ( and that it is not girl friend approve ) Anyway, i didn't lose my time, because even if I stop working with the chlorate cell, I jump into the world of "electronique and programmation" ( which is more appartement frendly)! Then, after university, I will be capable of building a fully automated chlorate cell without the need of national instrument !
WSM Posted July 29, 2012 Posted July 29, 2012 (edited) Nice find on the PVDF tube. If I wasn't mechanically stirring, that's be ideal. The only problem I can think of would be mounting it. PVDF doesn't solvent weld, so some method would have to be found to mechanically secure it.That's some good welding work, WSM. Welding heavier titanium can be a PITA, and past a certain thickness, spot welding has a hard time making a good joint. Remember with spot welding, the entire thickness would need to be brought up to heat, and that's tough to do with these light welders. My first spot welder was a homemade job, combining a rewound transformer, a foot pedal, and an industrial timer. I can set the timer for the weld duration, anything from 0.1 seconds on up, tap the pedal, and it energizes for that time period. That unit was used to spot weld very light stainless sheet for model gas turbines. When I tried to use it on heavier Ti, it choked, so I replaced the transformer with that exact Harbor Freight unit you described. Mounted the whole thing on a giant aluminum base which gets bolted to a benchtop. The timer makes for precise, even welds.One last thought - I was wandering through our local "Container Store" and admiring their large stainless trash cans. Has anyone tried a big cell made out of stainless steel? If the container is tied to the cathode, it should be cathodically protected and not degrade. Or, the entire container could be the cathode. I had the thought of using small CPVC pipe sections as pillars or stand-offs to hold the PVDF tube in position. PVDF can be welded, BUT the welded section needs to be under some mechanical pressure while welding plus requires some heat treatment afterward to relieve stress (if I remember correctly; a total pain without the right equipment). As for a stainless container, I have a stainless steel steam tray shaped like a metal beaker (volume about 2 liters) I was considering using for a cell container + cathode many years ago. I never tried it as such but still think it may work. I'm so happy with the performance of CP titanium cathodes that I shy away from using stainless steel in the cell liquor which would probably add unwanted metal ions, barring cathodic protection. Thanks for the kind words about the spot welding. I have more work to do and try, plus test the fabricated electrodes (I'm getting closer to doing test runs of a couple of my more complex or ambitious cells). WSM Edited July 29, 2012 by WSM
Arthur Posted July 29, 2012 Posted July 29, 2012 SASMAN on ukps years ago had a working lead dioxide setup and made perc however he found the a "stainless steel" food mixing bowl corroded as he watched it and he once lost a batch where it leaked. All stainless is not equal and the welds may not have the corrosion resistance of the formed sheet.
WSM Posted July 29, 2012 Posted July 29, 2012 SASMAN on ukps years ago had a working lead dioxide setup and made perc however he found the a "stainless steel" food mixing bowl corroded as he watched it and he once lost a batch where it leaked. All stainless is not equal and the welds may not have the corrosion resistance of the formed sheet. It appears the main advantage of titanium for cathodes is the fact that it is a "valve metal". What other metals are a "valve metal"? WSM
Mumbles Posted July 29, 2012 Posted July 29, 2012 I've always been curious as to what a "valve metal" really was. I always assumed it had something to do with what we'd commonly think of as a valve for liquids or gases. Boy was I wrong. I did stumble into some very interesting reading though. There are some lists of valve metals in there too. http://cr4.globalspec.com/thread/18783
WSM Posted July 30, 2012 Posted July 30, 2012 (edited) I've always been curious as to what a "valve metal" really was. I always assumed it had something to do with what we'd commonly think of as a valve for liquids or gases. Boy was I wrong. I did stumble into some very interesting reading though. There are some lists of valve metals in there too. http://cr4.globalspec.com/thread/18783 Thanks Mumbles, That was an interesting read. WSM Edited July 30, 2012 by WSM
WSM Posted July 30, 2012 Posted July 30, 2012 http://www.youtube.c...h?v=EzyXMEpq4qw Thanks Arthur, I enjoyed this video. I never ceased to be amazed by the abilities and skills developed by determined and talented people. I aspire to be numbered among them one day... WSM
WSM Posted July 30, 2012 Posted July 30, 2012 (edited) It appears the main advantage of titanium for cathodes is the fact that it is a "valve metal". What other metals are a "valve metal"?wWSM I know titanium is preferred in a marine environment and also in medical proceedures involving hardware for inplants. It also "self-heals" by forming an oxide coat similar to aluminum. It weighs less than steel while being about as strong. It naturally attracts hydrogen (not as well as zirconium or hafnium but it's much more available) which increases it's conductivity as a cathode. Fortunately, titanium is reasonably affordable despite the difficulty in winning and handling it; plus it's becoming more available on the surplus market due to it's wide use in aerospace and marine industries. Access to CP titanium will allow us to make durable and effective electrodes for electrochemistry. WSM Edited July 30, 2012 by WSM
Swede Posted July 30, 2012 Posted July 30, 2012 As far as SS goes, I'm not suggesting a trash can, although it MIGHT be possible, but more along the lines of a 40 liter or so surplused industrial process tank, which are usually made of 316 SS (best for chemical processes) and of a quality and thickness so as to not leak or fail. The trick would be to keep the tank energized 100% of the time. Just an amp or two would do the job. As soon as the power is off, the tank WILL begin to corrode. Perhaps a procedure could be set up so that a sacrificial anode is used to complete the circuit while the lid is off for maintenance or harvest. WSM pointed me to a number of PVDF process tanks on eBay. Not cheap, but they'd be outstanding. The only objection I'd have would be the lid. I found with my fabricated PVC tank that I needed no less than 8 6mm stainless studs and a viton seal, to seal the tank appropriately. These things operate at a positive pressure, and all it takes is 1/2 a PSI to cause some really nasty salt creep and a flow of heavily chlorinated gases that eat just about anything. A big aluminum block on my last tank had a corner exposed to a flow from the interior, and it literally dissolved the Aluminum at that corner... it simply disappeared. So unless one wants to run a tank outside rather than a garage or shop, these things neat to be VERY well sealed. I'm still convinced that the best tanks for large volume amateur use is either a large diameter PVC round section fabricated into a vessel, or a semi-sacrificial HDPE bucket-type cell. For 4 or 5 liters, food containers work but suffer badly. I mentioned to WSM that buckets used to contain granular chlorine for pool use are about as good as they can get, because they are heavy construction, well-sealed because they must keep moisture out, and generally pretty resistant to noxious chlorinated electrolytes associated with this process.
WSM Posted July 30, 2012 Posted July 30, 2012 (edited) As far as SS goes, I'm not suggesting a trash can, although it MIGHT be possible, but more along the lines of a 40 liter or so surplused industrial process tank, which are usually made of 316 SS (best for chemical processes) and of a quality and thickness so as to not leak or fail.The trick would be to keep the tank energized 100% of the time. Just an amp or two would do the job. As soon as the power is off, the tank WILL begin to corrode. Perhaps a procedure could be set up so that a sacrificial anode is used to complete the circuit while the lid is off for maintenance or harvest. Hi Swede, Ah, 316 stainless. Now you're talking! From my experience with cathodic protection, you'd do fine with a 1.2 to 2 volt battery connected properly to the container; probably with a small trickle charger connected in parallel with it to keep the charge up. I'm thinking a single lead-acid cell (2.0 Vdc) would work fine. If you set up the stainless tank, keep us informed of it's progess. WSM Edited July 31, 2012 by WSM
WSM Posted August 2, 2012 Posted August 2, 2012 Hi All, My posts may be spotty for the next couple weeks. I'm travelling next week to see my Son's graduation from college and immediately taking off to the PGI convention afterward. If any of you are going to PGI, look me up (or pm me). WSM
Swede Posted August 9, 2012 Posted August 9, 2012 Congratulations to your Son - a big step in life! I've got three, one graduated, one a college senior, the other a college freshman. Have a safe and joyous trip!
ANFO Posted August 9, 2012 Posted August 9, 2012 It doesn't make large quantities, but I thought I'd just throw it out there, if it hasn't already come up: you can make potassium chlorate from bleach and potassium chloride. All you have to do essentially is boil the bleach and mix in a solution of potassium chloride. Video of how to here
pyrojig Posted August 10, 2012 Posted August 10, 2012 (edited) @ Anfo..That is a painful task to obtain very small quantities of chlorate . While it does work the process is downright dangerous to the person Via .. toxic hyperchlorides that burn the @#$@#@ out of ya, and can blind you, also the toxic chlorine gases produced . There is always the filters that catch on fire, after starting to dry out. Not my idea of safe. I'd stick to electrochemistry on this one. @ WSM.Congrats as well, That is a big step toward to the future for these kiddo's . Edited August 10, 2012 by pyrojig
ANFO Posted August 10, 2012 Posted August 10, 2012 @pyrojig what you say is true, I gave it a try, and the amount produced was not economical, more of a science experiment than a viable long-termsource of chlorate. Still, the forum heading did stipulate "any type of way" so I thought I'd contribute
WSM Posted August 11, 2012 Posted August 11, 2012 Congratulations to your Son - a big step in life! I've got three, one graduated, one a college senior, the other a college freshman.Have a safe and joyous trip! Hi Swede, Thanks. He graduated yesterday and all is well (I'm the proud Papa, alright! ). I'm off to Chicago today and then a drive to LaPorte. I'm looking forward to seeing what this new site is like. I'll share my thoughts later... WSM
Swede Posted August 14, 2012 Posted August 14, 2012 Wow, I'm bummed... I went to Home Depot today to pick up a few items connected with electrochemistry. Grabbed 4 of those 5 gallon HDPE buckets, nice and cheap, $2.75 each, and lids - they have two varieties, one with a rubber gasket, one without a gasket, both were $1.28 apiece. These things are great for storing bulk chems, but my main goal was to pick up a 40 lb bag of KCl... and they didn't stock it any more! They had been my KCl source from the beginning. I need to find another source. The goal is to set up a minimal cell using very cheap components that will make 200grams/liter of KClO3, or, for a 5 gallon HDPE bucket, approximately 3.5 kilos worth. I'll be doing some documentation on it, but first I've got to find some KCl locally. One additional goal is to use derived process numbers for both pH control using a drip system, and efficiency calculations so that measuring chloride ion will not be required. I will however check both during the run so as to verify those numbers. Along those lines, I exported a couple of items from my eBook. The first is the entire chapter on efficiency... how it is derived, the math behind it, and the numbers. The second file is a "worksheet", set up like an IRS tax return page, for those of us math-challenged. It is called Length of Run Worksheet for Potassium Chlorate Electrolysis. The first file, the efficiency chapter, has the worksheet in it, so if you download the first, you won't have to download the second. The chapter contains a very basic chemistry review. In there is a fun bit of trivia about Avogadro's number, the mole. The question you must try and mentally answer before you read the chapter - this is all in fun - "You have a mole of U.S. pennies. How many nuclear aircraft carriers do you need to equal the MASS of the mole of pennies?" The number may surprise you! Enjoy File 1: effchap.pdfFile 2: wsheet.pdf
patsroom Posted August 14, 2012 Posted August 14, 2012 Swede , after looking thru the form you made now I know what you do for your vacations: You work making new forms for the IRS ! But hey it is nice to see you back. I know you hated to return so soon because the girls were pretty and the beer was cheap!
WSM Posted August 14, 2012 Posted August 14, 2012 Wow, I'm bummed... I went to Home Depot today to pick up a few items connected with electrochemistry. Grabbed 4 of those 5 gallon HDPE buckets, nice and cheap, $2.75 each, and lids - they have two varieties, one with a rubber gasket, one without a gasket, both were $1.28 apiece. These things are great for storing bulk chems, but my main goal was to pick up a 40 lb bag of KCl... and they didn't stock it any more! They had been my KCl source from the beginning. I need to find another source.The goal is to set up a minimal cell using very cheap components that will make 200grams/liter of KClO3, or, for a 5 gallon HDPE bucket, approximately 3.5 kilos worth. I'll be doing some documentation on it, but first I've got to find some KCl locally. One additional goal is to use derived process numbers for both pH control using a drip system, and efficiency calculations so that measuring chloride ion will not be required. I will however check both during the run so as to verify those numbers.Along those lines, I exported a couple of items from my eBook. The first is the entire chapter on efficiency... how it is derived, the math behind it, and the numbers. The second file is a "worksheet", set up like an IRS tax return page, for those of us math-challenged. It is called Length of Run Worksheet for Potassium Chlorate Electrolysis.The first file, the efficiency chapter, has the worksheet in it, so if you download the first, you won't have to download the second.The chapter contains a very basic chemistry review. In there is a fun bit of trivia about Avogadro's number, the mole. The question you must try and mentally answer before you read the chapter - this is all in fun - "You have a mole of U.S. pennies. How many nuclear aircraft carriers do you need to equal the MASS of the mole of pennies?" The number may surprise you! EnjoyFile 1: effchap.pdfFile 2: wsheet.pdf Hi Swede, I'm sorry your source for KCl dried up (I'd be bummed out, too!). If you have more than one Home Depot in the area, you may want to check and see if they carry it (maybe it was a manager's decision for just the one store, hopefully). Another source in my area is grocery stores who carry water softening salt, some of them have the potassium option. Good luck with your search for a local source. I like the looks of your paper on "end-of-run" calculating. I look forward to giving it a thorough study when I'm not enjoying a week of sleep deprivation and pyro euphoria. Thanks very much for sharing it with us. WSM
bikemaster Posted August 14, 2012 Posted August 14, 2012 My home depot stop to carry KCl more that a year ago too... But Windsor (their supplier where I live) is still carrying it! With some research, I find that Windsor is now selling to Rona and that Rona is now selling it! http://www.rona.ca/en/potassium-chloride In US, I that one off the big salt supplier is Morton. Try to do the same thing with them to see if other harware center is carrying their potassium chlorate. With a quick look,I find that they sell to home depot, Lowe's and walmart!
Swede Posted August 17, 2012 Posted August 17, 2012 Weird - I thought I replied to this thread, but my reply is gone? Anyway, to repeat, I found 3 bags of KCl at a local ACE hardware, which for our non-USA folk, is a much, much smaller store than the big-box Home Depot and Lowe's. For whatever reason, at least in this location, it's becoming harder to find. Anyone interested in this process, buy it when/where you can. Having to have it shipped to you is going to cost a fortune.
Mumbles Posted August 17, 2012 Posted August 17, 2012 If you ask, some of the bigger stores will order it for you and not charge you shipping to the store. It's just a matter of it getting thrown on a truck from a distribution center. When I worked at a hardware store we would do this all the time, or get it brought over from other regional stores.
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