In January ’05, when I was developing the whole process for making Mojolevers, I had to decide whether to use paint or powdercoat, and whether to do it myself or contract it out. Ultimately I discovered that powdercoat was far more durable than paint, and that I could economically do the work myself; all I needed was a powdercoat gun and a curing oven.
The big problem was that I needed a big oven. The Mojolevers were to be nearly three feet long, and although hobbyist powdercoaters were successfully using crappy old kitchen ovens for their work, such a beast wouldn’t be nearly big enough to accommodate the Mojo’s. In fact, a commercial powdercoat oven big enough for the job would have cost thousands of dollars! What to do?!?!
Make my own, of course.
I started with a used electric oven from the classifieds for $30:
OK, you caught me: that’s actually just a catalog photo. But the one I got is more or less the same thing, just a little crustier. First step was to remove the range top and console, and then cut a gaping hole in the top of the oven chamber, making room for the vertical extension. After that, it was down to a bunch of sheet metal work:
All of the sharp-cut edges are folded back for safety, and the pieces are assembled with about a zillion pop-rivets.
The heating element has limited power, and of course it was designed for heating only the small original oven enclosure. I knew if I wanted to hit 400 degrees F in that big thing, I’d need a double-wall design for the extension, with a generous layer of insulation. And so that’s what I got:
After building and attaching the inner sheet metal surface, I welded up some angle-iron structure (visible in the above photo) to bear the weight of the Mojolevers. Finally the outer layer went on, and then a cap strip:
The freshly powdered Mojolevers get lowered in from above, and then an insulated lid gets set in place:
That orange stuff is my lame attempt at a gasket using a bead of high-temperature silicone RTV compound.
The bottom end of the Mojo’s hangs within a couple of inches of the heating element. To avoid direct radiative heating that would incinerate the powder at the end of the bars, I installed a bent-metal heat shield just above the element:
The ends fold up so as to protect the bars from a direct view of the element, while simultaneously allowing the maximum possible airflow to keep the element itself from overheating and burning up.
After I first finished it, I was worried the oven wouldn’t be able to hit
400F. But it did, and the thermostat cycled the element on and off at a moderate
interval, indicating the burden wasn’t too great. It was a lot of work,
cutting/bending/riveting sheet metal by hand, but the whole thing works
beautifully.
When loading Mojo’s into the oven from a stepladder, I had initially been placing one foot on a 1-inch-wide ledge at the bottom of my sheet-metal extension. Teetering precariously several feet above the ground, past the edge of my stepladder with 30 pounds of steel bars in my hands, I knew this was a disaster waiting to happen. So in February 2006, I added a six-inch-wide step around the perimeter of the oven:
It’s welded from a combo of 1/8” steel plate and 1/16”-wall square tubestock. The whole assembly is bolted to the structure of the oven, and I covered the top surface with grit tape for traction. This gives me much safer footing when loading Mojolevers into the oven.
In the above shot, that's the original thermostat and light switch, installed in a Radio Shack project box that's been screwed to the side of the oven. And of course, no appliance is complete without a complete set of Magnetic Poetry installed on its front panel:
Questions? Comments? Email me!
©2006, Mitchell P. Patrie