Tell us about yourself!
I've gotta say, while I agree with you, cork is not a bad choice. It repels liquid and like most wood is quite a good insulator.
The power going into the device is DC, not AC.
Yep, but your comment stated that the capacitor wouldn't work as it will always allow some AC fluctuations to the device. Which is a little misleading. The fluctuations you are still DC. They were caused by AC, but there is no "AC" power going through. The difference is important as AC and DC are effected by caps in a very different way.Using caps can definitely smooth the signal over to the point where noise isn't an issue. Linear regulators are useful, but you shouldn't have to go out and buy one for something like this if you already have a selection of caps laying around.
Data is also DC. Data goes through on a steady voltage, It just switches on and off quickly. AC refers to a waveform with a positive and negative voltage in respect to ground.
Be careful with the welded on bottom piece. If one piece of steel heats faster than another repeatedly, the whole weld can fail. If that were to happen right before you go to pour, you could have what is commonly known as "a very bad day".
I've used a 2.5"ID cast iron cap and pipe. It was a bit expensive, and hard to get to temperature in my furnace, but its rock solid. Cast iron melts at a lower temperature than steel, but still much higher than aluminum.
Caps Lock to Control: Hardware level Mechanical keyboard mod
Cut throat razor