Step 1: Strip and Cut Your Tank.
Next you need to strip the tank down. there is probably a better way to do it but I just knocked off the top with a hammer then used some tin snips to cut down the side. then remove the insulation. I saved the tin and insulation for future projects.
Next mesure and mark your line to cut. I cut mine just below the top heating element. measure down and mark a line all the way around.
Now cut it. I used my angle grinder with a cutting disk. don't forget you safty glasses! metal in the eye hurts! After you finish your cut use the grinder to smooth out the edge so you don't cut yourself.
Step 2: Build Your Box and Wire It Up
Cut your top and bottom board first. place it where it will be on the tank and measure from the tank up to the top of the board. Cut your end pices this wide. This way your box will kind of follow the curve of the tank. Cut your end boards and screw it together.
Next drill a hole in the side for your power cord
Now mix up your glue. I used dollar store epoxy. stick it on and let it set up.
Silicone the edges with silicone the can take the heat. High temp silicone is your best bet I think. But other might work as well.
Now pull your power cord through the hole in the side and wire up. Connect the ground to the ground on the thermostat plate. The thermostat should be hooked up to the element so connect one end of your power cable to the heating element and one to the thermostat. Note that even if the element is 240v it will still work on 110v
Step 3: Set It and Close It Up
Cut a plate to cover the front of the box and screw it on. You could use hinges and a latch but I think once it's set I won't need to open it up so I am not worried about it.
Next fill it with water and plug er in. make sure you test the temperature with a thermometer and adjust your thermostat accordingly.
Remember that someone threw this tank out and you likely don't know why. The element or thermostat might not work. If the pot dosent work trouble shoot the electronics.