Powdercoating is an excellent coating system, superior to paint in many ways, and is now available to the hobbyist through the coating guns offered by Eastwood, Columbia Coatings, Harbor Freight, and others. The main deterent to hobby use, though, is the fact that the coated object has to be baked at temperatures as high as 450 degrees, and for time periods up to 25 minutes, depending on the type of powder used. For smaller objects, an old kitchen oven can be used, but when the size of the object increases beyond that which will fit into a kitchen oven, the equipment cost goes up at a breathtaking rate.
One of my hobbies is restoring and riding old three-wheelers, four-wheelers, and motorcycles. The kitchen oven I have in my shop will barely accomodate a wheel, and a swing arm would be out of the question. I decided to build a powedercoat oven to use in coating objects up to the size of an ATV or motorcycle frame. I wanted the oven to be collapsible so that it could be stored away when not in use. There's not much hard info on the internet about building ovens, but I contacted a few people that had experimented with this sort of thing, then made a few decisions of my own, and forged ahead.
The oven is assembled from a series of panels which is actually 2" rigid fiberglass board wrapped in 28ga sheetmetal. Each panel is different from the others, but all have at least one dimension of 36", which is the largest size that my brake will handle. All fastenings are steel pop rivets, except a few screws which hold the panels together to form the oven. The base is a lightweight frame built up of light gauge metal drywall studs, with burner pans filling in the open areas of the frames.
Heat is provided by 4 salvaged kitchen oven burner elements, of about 3000 watts each This was the real uncertainty for me, whether the element would heat up the large volume quickly enough. As it turned out, the oven heats up to 450deg in about 10 minutes. Temperature control is provided by a scrounged kitchen oven thermostat which controls a 50 amp definite purpose contactor to turn the elements on and off. The temperature floats a bit but it seems accurate enough.
The total draw of the heating elements is about 12kw. My local power rate is 8.7cents/kwhr, so the oven would cost about $1.04 per hour to operate.
Here is a front view of the oven. Inside dimensions are 24" wide x 36" high x 72" deep. Two of the four heating elements are visible. The shiny bar across the bottom about 1/2 way into the oven is actually an intermediate support member. It might not be clear from the picture, but the elements are recessed about 1-1/2" below the front lip of the base. A pair of rails, made from small channel iron will be laid the length of the oven and a trolley will be used to carry the coated object into the interior of the oven.
The trolley is made from 2" angle iron with 4ea fixed casters. If I were to do it over, I would use 1-1/2" angle so that the wheels would protrude at the bottom more. The various rods and pipes that protrude upward are for supporting the items to be coated. Scroll down a little further...
and we have a picture of an ATV frame mounted on the trolley and being loaded into the oven. The rails mentioned earlier are in place and visible in this picture.
Here is a wheel being loaded on the trolley.
A picture of the top of the oven showing the view windows. These windows were salvaged from two scrapped kitchen ovens. The black box on the side of the oven is the interior light, a part also taken directly from the kitchen ovens.
For a closer look at how this oven was constructed, click here to go to the Construction Page.
This website is presented for the enjoyment of its readers only. The owner of the website is not a professional engineer or designer, nor does he purport to offer advice or consultation on the subject of oven construction. The fabrication of heat producing equipment such as an oven is an inherently dangerous process. Installation of electrical components requires specialized knowledge of the trade and of electrical codes. Anyone considering the construction of such an oven should consult the appropriate professionals for preparation of a qualified design. Under no circumstances shall the website owner be responsible for any loss or damages, regardless of severity, that arise from the use of information published on this website.