I'm getting ready to make the move to all grain and trying to decide what to do about a brew kettle. I want to brew indoors - don't have a water source in my garage and it's too hot to be outside in the summer anyway. Also don't need more than 5 gallon batches. I really like the idea of going electric, but can't get a large (10 gallon) pot on my electric stove (even 8 gallons would be awkward). I had considered using a water heater element mounted in the kettle but I'm a little worried about the things I'm reading here about rust and the zinc coating disappearing from the elements - also worried that cleaning the kettle would be difficult without taking out the element. I would like to use a stainless "Megapot" with the sandwiched aluminum bottom for even heating.
In one thread I saw someone (IIRC it was the "Bargain Fittings" guy) who had taken the coils and controls from an electric stove and made his own stove with three of the coils placed close together. I like that idea, but don't have an old stove - there are some on Craig'sList, but I don't have a truck to pick one up and don't want to have to dispose of the remains anyway, and so far I haven't found a drop-in range top for a reasonable price.
So I looked around a bit and see that I can get 6 inch 1250 watt coils for about $18. Now I'm thinking, why not build a "burner" using a flat piece of metal with 4 holes for six inch elements placed close together, mounted on legs (metal tubing?) and braced as required to support the weight. New element temp control units are pricey, so use 15 amp SPST toggle switches (about $5 each) to turn on 1,2,3,or all 4 coils as needed. If I could turn on one of the elements to half power, I could get even more levels of power control. The 240 v outlet I have access to doesn't have neutral, only the two hot lines and safety ground, so I can't use 120 v (which would only be 1/4 power anyway), but why not use a rectifier (10 or 15 amps should be enough) and another toggle switch (SPDT) to allow the fourth burner (only) to be selectable between full 240 v power and half-wave rectified 240 v power. This would give power levels of 625, 1250, 1875, 2500, 3125, 3750, 4375, and 5000 watts, depending on how many elements were turned on and whether the fourth element was on full or half-wave current. I hope this would be a fine enough level of control to maintain the boil level I want. I don't know what effect this would have on a GFCI, but it seems to me that it shouldn't have any because even with the half-wave rectified current, the same amount of current is always flowing in each of the hot lines - any electricians out there who might know if this would cause problems with the GFCI?
This is just a wild idea I had, so feel free to shoot it down before I spend any money on it.