How to make waterproof underground electrical connections

We needed to run 2-2-2 aluminum wire out to our automatic livestock waterers to provide electricity for the built-in heaters, and had to make a few splices along the way. This may seem like overkill and lots of work, but so is finding, digging up, and repairing these connections after a short! Here's what we did to make them waterproof:
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Step 1: Cut a piece of 1 1/2" PVC pipe about 1' long and slide onto one end of the wires BEFORE connecting wires (see why in Step 4 below). Connect wires with an aluminum splice connector and apply a light coating of Ox-Gard anti-oxidant compound (Gardner Bender, #OX-100B) or similar product Step 2: Wrap splices first with electrical tape, then with rubber tape
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Step 3: Apply a liberal coating of 3M Scotchkote electrical coating (#43906) and then wrap with a second layer of rubber tape. Don't worry - it's cheap! Up close of splices covered with electrical coating. Be sure to apply it past the end of the rubber tape and onto the wires. It only takes a few minutes to dry and forms a hard, waterproof layer
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Step 4: Now slide that piece of PVC pipe back over the connections and fill it with 100% silicon on both ends Ain't no water ever gonna get to your connections now!