DIY Powder Coating Oven Gets Things Cooking

diy-powder-oven

[Bob] needed an oven for powder coating metal parts. Commercial ovens can cost thousands of dollars, which [Bob] didn’t have. He did have an rusty old file cabinet though.  And thus, a plan was born. The file cabinet’s steel shell would make a perfect oven body. He just had to remove all the drawers, sliders, and anything combustible. A few minutes with an angle grinder made quick work of the sheet metal. The drawer fronts we re-attached with hinges, allowing the newly fashioned door to swing out-of-the-way while parts are loaded into the oven.

The oven’s heating elements are two converted electric space heaters. The heating elements can be individually switched off to vary power to the oven. When all the elements are running, the oven pulls around 2000 watts, though full power is only used for pre-heating.

[Bob] used a lot of pop rivets in while building this oven, and plenty of them went into attaching sheet metal guards to protect the outside of the heating units. To complete the electrical equipment, a small fan was placed on top of the oven to circulate the air inside.

The most important part of the build was insulation. The entire inside of the oven was coated with aluminum foil and sealed with heat proof aluminum tape. On top of that went two layers of fiberglass matting. Metal strips kept the fiberglass in place, and the stays were held down with rivets. One last layer of aluminum foil was laid down on top of the fiberglass. Curing powder coating produces some nasty gasses, so [Bob] sealed the gaps of the oven with rolled fiberglass matting covered by aluminum foil and tape.

[Bob] was a bit worried about the outside of the oven getting hot enough to start a fire. There were no such problems though. The fiberglass matting makes for an extremely good insulator. So good that the oven goes from room temperature to 400 °F in just 5 minutes. After an hour of operation, the oven skin is just warm to the touch.

If you need to find [Bob], he’ll be out in his workshop – cooking up some fresh powder coated parts.

 

PCBs with powder coat

pcb

The toner transfer method of PCB production should be a staple in every maker’s bag of tricks. That being said, it’s a far from ideal solution with a lot of things that can go wrong, ruining hours of work. [Ryan] thinks he has a better solution up his sleeve, still using heat activated toner, but replacing the laser printer with a powder coating gun and a laser engraver.

[Ryan] is using a powder coating gun he picked up from Amazon for about $100. The theory behind it is simple: particles of toner coming out of the gun are statically charged, and bonded to the grounded copper clad board. In real powder coat shops, this coating is baked, resulting in a perfectly hard, mirror-like finish. [Ryan] skipped the baking step and instead through the powder coated board into a laser engraver where the PCB design is melted onto the copper. After that, wash the board off, etch it, and Bob’s your uncle.

What’s really interesting about this method of PCB production is that it doesn’t require a very high power laser. [Ryan] was actually having a problem with the toner burning with his laser engraver, so it might be possible to fab PCBs with a high power handheld laser, or even a Blu Ray laser diode.

Color-matching powder coat paints

[Zitt] is sharing some methods he’s honed for color-matching powder coat paint. He developed these techniques while restoring a 1982 Star Trek coin-op machine. The image above shows a paddle used for the game. The plate that houses the control was beat up, and he needed to repaint it but wanted to make sure it didn’t look out-of-place with the molded plastic that surrounds it.

He gets his powder paints from Harbor Freight, a favorite depot for hackable goods (like drill motors, or metal carts). Usually these paints would be applied by attracting them to the piece using electrostatic charges. [Zitt's] not doing that, but applying them with a paint sprayer instead.

The first step is to match your color. He’s using an electronic color matching device which gives data to plug into a chart on the web for a color match. Once you’ve got a formula, mix up the powder coat, and then dissolve it into some Methyl Ethyl Ketone. This goes into the spray gun and is applied in an even coat. Before heading into an oven for curing, it’s important to wait for this coat to dry. [Zitt] observed some boiling MEK on a wet test piece that left an undesirable texture on the baked paint after curing. After running a few test pieces he picked the blend that was the best match and then painted all of his restored parts.

Powder coating at home

[j_tenkely] wanted to do his own powder coat painting at home so he built everything he needed, including a coating booth and baking oven. The oven is double walled and built around a frame of steel building studs. Electric oven elements are controlled by a digital control panel and thermostat.

A spray booth is fashioned from a large storage bin. The powder coat gun used in this setup is a commercial project. But don’t fret, this is something you can build rather than buy.

[Thanks goat]

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