old coffee pot heat exchanger?

So I've been toying with a few ideas for getting a recirculating system done and have a good grasp on the theory. The other day while going through the *crap* in the garage i found a preettyyyy darn old percolator-style coffee maker. It has an inner chamber of aluminum, and a heating element at the bottom that transfers heat to the entire unit. It even has an outlet valve at the bottom that is easily replaceable with a new fitting.

This this was designed to get a gallon or so of water up to coffee temps to recirculate (percolate) through its own system in probably 10-15 minutes. It's definitely got enough juice to hold flowing wort at 150-155 F. I was thinking of putting a whole in the lid, refitting the outlet, adding a volume knob to the electric element as a 'control' knob, and using this thing for a RIMS. Ideas? Suggestions? If i could find a way to make it relatively air-tight, I could also probably get away with leaving it at a level equal or below the mashtun, and allowing the pump to do its thing, rather than having to put it above and control flow.

feedback appreciated

Do you know the wattage of the heater?

Rather than making it air tight put a heat exchange coil in it.

the urn i use as a mash tun is a 100cup 1500watt unit. the wattage is usually listed on the bottom plate.