Amazing... this is the second project in a few days to fail in a spectacular fashion. The first was the experimental "cage" electrode mentioned in a previous blog. It was a lot of work with expensive materials (Ti wire and virgin PTFE stock), and the outcome was definitely less than satisfactory. I'll take the blame on that one, because simple internet research would have shown me that Ti wire, in the cross-section that I used, was not adequate to handle 20 to 40 amps.

This one is different. I have been screwed by substandard acrylic sheet plastic. Allow me to elaborate.

The odd thing on the left is something that I have been saving for years. I have been tempted to throw it out, but I knew, someday, I would find a use for it. That day has come. What it is: an ozone reactor for a reef aquarium. Many years ago, I kept a 55 gallon reef, and it was a thing of beauty and much joy, despite the freakish expense. To keep a reef aquarium healthy requires life-support equipment that would do NASA proud. This thing would inject water and ozone into an intimate mix; the ozone would do its job of sanitization, and the water would be reintroduced into the aquarium. It is a very high quality acrylic cell. Look at the size compared to my 4 liter Lock & Lock cell! This thing should produce two kilos a batch, easily.

The main problem was the lid. The lid is a complex, built-up affair designed to inject water and ozone. I thought it would be easier to make a new lid, rather than adapt the old. A quick trip to the local hardware store, and I had a 1/4" sheet of plexiglass in my hands, ready to transform. The following pictures show the work and care I took into making a world-class lid for this deluxe cell...

The small pieces are doublers for the electrode shank area. I used a mixture of xylene and tetrachloroethylene to glue the pieces onto the disk, and put it aside for the night.

This morning, I wake up, ready to finish this lid, and this is what I found...

The thing had spontaneously cracked in a horrific fashion. I've done a lot of acrylic work over the years, and it is tricky stuff to work with, but this is the worst I've EVER seen. It was as if the sheet had huge internal stresses from poor manufacturing, and the cracks propogated from all of the slots and holes I machined, all the way to the rim. One section (at 5:00) was badly crazed. Amazing, crappy luck. A whole day of work, blown.

The "Super Cell" will live, but I am going to have to adapt the original lid with some careful machining. The hard part is in generating two 1/16" slots clean through the material for the electrode shanks. And I DON'T look forward to doing that to the original lid, which is almost 1/2" thick.

The good part, when this is done, it's going to be awesome. There is a machined o-ring groove in the lid which I am going to pack with PTFE cord. If the acrylic can shrug off the chemsitry of this cell, it should last a LONG time.

Update on the Lock & Lock containers as (per)chlorate cells... while useful and useable, they are NOT a good long-term option. As the plastic heats, the seal effectiveness diminishes, and there is too much leakage. I will also try the Klick Klack container (from the previous blog) which I hope will do better. But if the "Chlorate Tower" comes online, it will definitely be the best.

Look to the aquarium trade for cells and plumbing material. There are a number of companies that do custom acrylic work. If you can draw it, or describe it well, they can build it. You could always say it's a refugium, or that you are doing research requiring an airtight pressure vessel - you don't have to say it's a perchlorate cell unless you want to.