So much attention in internet literature related to (per)chlorate production is paid to the electrodes, while very little research material focuses on the cell itself. If you google "electrolytic cell" or "chemical cell" you'll find very little, certainly nothing like "Wild Bob's Chlorate Cells, BUY NOW online!" The electrodes are there, but you have to make the cell yourself.

I've used the Lock & Lock containers with great success, but I am almost always on the lookout for something bigger and better. Food storage technology has come a long way, and that is where most guys are going to turn when the time comes to make a cell. I dropped by today to a local "Bed, Bath, and Beyond" store, which is a U.S. chain that carries many food storage options. I found a container that impressed me.

The concerns with chlorate cells themselves, apart from the electrodes, are many and varied. The cell must be genuinely airtight (and subsequently vented with a tube) unless you plan on locating the cell outside. The typical Rubbermaid tub simply won't hack it... NOT airtight. I cannot begin to describe how noxious and plentiful are the Cl₂ and hypochlorite smells these things produce. The container must have a gasket, and the lid must tightly seal that gasket to the rim of the container. Size - unless you just want to play a bit, consider 4 liters as the minimum. The starting salts are cheap, so you may as well go for it, quantity-wise. A 4 liter cell theoretically produces about a kilo of KClO₃ from a saturated KCl electrolyte before it is time to recharge. Finally, the plastic itself must resist the harsh environment (and heat) the cell creates. From personal experience, polyethylene and silicone both are excellent, nylon good, vinyl tube very poor. Fortunately, most of the better airtight containers I've seen are PE plastic with silicone gaskets. These are good to go.

This is a good one! Click Clack food storage containers. This 4 liter container was $9, and I was very impressed by the thickness of the plastic, and the most excellent lid which firmly clamps the body of the cell.

In the second picture, you can see the thick silicone gasket which forms a true airtight seal. Perfect!!

The lid is very thick PE plastic. The body is a bit different from most of these stackable containers in that it appears to be acrylic. Any cell will need to be drilled and/or slotted for electrodes and exhaust tube fitting, and while acrylic can be machined and cut, it is much trickier than PE plastic, so unless you are confident that you know how to drill acrylic, keep all your drilling and cutting isolated to the lid. Most cells work in this manner anyhow... I can see no reason to be cutting the body.

Whaichever container you choose, pick one that is relatively transparent. It would be no fun whatsoever to have to pop the lid to view the contents. That goes beyond being simply irritated by a stray whiff of Cl₂ to downright dangerous; a possible big hit to the lungs. Remember, Cl₂ gas was used during WW1 as a chemical warfare agent. Noxious stuff.

Use real fittings for the exhaust tube/fill ports, and keep all of your fittings plastic. If you simply drill a hole in the lid and press some tubing in there (like I did initially) you will get leaks, and worse, some significant salt creep outside the cell. Messy and dangerous. It's tempting to wipe up the salt creep with paper towels, and I think it is possible to create a real fire hazard that way after the chlorate-laden paper towel dries. Try burning a dried filter paper that has been used to filter chlorate... it's eye-watering. For the plastic fittings, teflon (PTFE) is the ultimate, but quite expensive. Polyethylene is good, and nylon is better than nothing, but be prepared to replace them periodically. Avoid metal entirely. It will corrode and pollute your cell!

For adhesives, as I mentioned in an edit to the previous blog, hot glue sucks - I don't know why I championed it - silicone glue (look for 100% silicone on the label) rules in this application. If you need silicone glue to stick to PE plastic, scuff the slick surface of the plastic a bit with fine sandpaper. This will help the glue adhere much better than if you did not.

Keep in mind that the life expectancy of your electrodes is much greater than the plastic lid and the cell itself, so you'll want to be able to cleanly remove the electrodes, and rebuild the cell. This requires a glue that can be stripped off of the electrode shanks.

Some other fun goodies I picked up at this store...

A meat marinator! It's a big syringe with a plastic "needle." What's it for? It will be used to draw electrolyte samples from the exhaust port without having to pop the cell lid. I use the tube port I install on the lid to both gather samples, and to top off the cell with a wash bottle full of sat. KCl + HCl. The port ID is quite small, and this needle will sneak easily into the electrolyte to gather the 5ml I need to check for remaining chloride quantity. From there, it will go into a precision pipette. When diluting 50:1, the small sample needs to be very accurate indeed.

Finally, I could not resist this bargain... Six small stainless steel bowls for $5. These are very handy for drying small samples of just about anything. It's pretty interesting how you view a normally boring place like a housewares store, when you have chemistry on the brain!

After I bought this latest cell, I remembered something I'd stashed away years ago, when I was keeping a reef aquarium. It's a 3' tall, beautifully crafted, airtight, acrylic reaction cell for ozone, with probably a 12 liter capacity. 12 liters of electrolyte, times 60 to 80 amps, equals multikilos of product. I'm going to convert it into a (per)chlorate cell that will be absolutely killer, but that will have to wait for another blog!