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Medical iodophors like Betadine (and teat dip for cows) are made up of iodine complexed with povidone (often written PVP). That formulation is extremely popular. But: BTF iodophor is complexed with butoxy polypropoxy polyethoxy ethanol. IO-Star is complexed with butoxy polypropoxy polyethoxy...

You want to go for 12.5 ppm for a fairly quick kill (25 ppm for a faster kill, and a more careful rinse). You get 12.5 ppm by adding that solution (1% iodine, or 10,000 ppm) at 1.25 mL per liter of water. 1.25 mL/L * 5 gallons = 24 mL. That's equivalent to what another poster suggested: 5 tsp...

That's a good point. I compounded liquids and solids, but it was a nightmare and I would not recommend it unless you have a vacuum dessicator and a ball mill. I don't. But since my source of sodium silicate is also liquid, I think next time I'll consider this a liquid/solid two-part product...

That makes perfect sense to me, but it should also have surfactant. (Any laundry cleaning product will have surfactant, but if you are making it yourself from straight chemicals, add a surfactant. Dish soap is fine. Triton X-100 is one that the patent suggests.)

Wow, that patent is a fantastic resource! After reading that, there's no way a simple percarbonate+silicate mix is as good as the real thing. It needs a builder, a chelating agent, a surfactant, and possibly a sequestering agent. (I don't remember which role the silicate plays.) But that patent...

I think you need a 555 timer, any potentiometer, a transistor, a couple resistors and ~2 capacitors. Whatever is currently driving the fan will stay the same, but you'll hook up this new circuit to the speed-controlling wire. (If it's a 2-wire fan, it won't have a speed control wire, and a...

Does your fan have 4 wires? If so, you can do something even better than PWM power reduction: you can give it a PWM signal that tells it how fast to run, and the fan will control its own speed based on what you tell it. I'm not sure how deep down the rabbit hole you'll want to go, but this would...

My current stir plate is basically a computer fan. The torque isn't bad, as the fan will try to control its own speed (4-wire fan taking a PWM signal for speed), so power isn't automatically reduced when I turn it to low speed--only when it's moving too fast. There must be some kind of feedback...

@divrack Yep, I'm thinking of "spiking" the rest of the cleaner by adding 10% TSP to stretch it out and have a phosphate output that's not significantly worse than fertilizing a garden once a year. I was able to get sodium silicate as well, and I'll use more silicate than TSP.

That is really interesting, thanks for letting me know! I couldn't find an actual data sheet, but I found references that say old PBW datasheets mentioned containing phosphates. Maybe the older formula either was percarbonate+TSP or a more complex formulation that contained some TSP. (I can't...

No, no, no. PBW does not contain trisodium phosphate. The ingredient is sodium metasilicate. The full formula is "70% sodium percarbonate, 30% sodium metasilicate". So why the confusion? A long time ago, someone read the acutal ingredients and tried to make it easier for others by substituting...

Peptone is one of the major organic nitrogen sources used in microbiology, and it's easy to buy or manufacture yourself by using an enzyme to digest protein (soy protein isolate or casein isolate with no lactose). It's not so easy to get Fermaid O in my country, and it looks like it just...