Powder Coating Oven Build

This was a powder coating oven I built in 2010, 5 years before moving into our current location. This is a step by step sequence on how I built a commercial powder coating oven. Most of the high temp wiring was removed from a donor Kenmore oven range. I attempted to use the controller from that oven, but it burnt out right away. Scroll though the photos to see the progression.

Staring the Build

I started with a 4′ x 3′ base and lots of custom cut 22 gauge cold roll steel. The inside was 6ft tall

Used Harbor Freight casters. I thought these were cool because they were rollerblade style wheels, clear and different than all the other casters they had in stock. I need to be able to move my oven around when I move into another shop.

6′ uprights & the frame top on.

 

Skinning the Oven

Starting on the skins. I used hot rolled steel, which was not galvanized. I should have used galvanized because over time, the steel started rusting. See photo of that below. The mild hot rolled steel was much cheaper, and since I was on a really low budget at the time, I couldn’t really afford the galvanized. Stainless steel is what most commercial ovens have, however the cost

Brace for the control box

Door frame corners with 90º bends to keep the seams cleaner. Wire tied the corners to pull everything into plumb.

All the braces in. Ready to start on insulating and skinning the outside.

Last of the sheet metal picked up at Ballard Sheet Metal Works. Custom made door, inside door panel and back panel. Had to use 20 gauge for the back, and doors due to the larger size. Wasn’t that much more, but the 22 gauge did cut down on the weight. Eurovans also make great sheet metal haulers too.

Insulating the Oven

All insulated with barriers on all the studs and high temp tape. The R12 home insulation is not technically rated for oven use, The critical temperature of R12 insulation is rated at 600ºf, which is well below the 400º temperatures the oven reaches. I never had any issues with this, but I highly suggest using the correct insulation if it’s in your budget. The correct insulation that should be used is Rockwool or Kaowool. This high temp insulation is much more expensive, yet is UL listed and has a critical temperature of around 2000º-2400º.

More Skins

Outer skins going on, 22 gauge hot rolled steel.

More skins + controller, which will be replaced by a different controller soon.

 

Wiring

Wiring up the oven with high temp wires from the donor oven. I used conduit so I could run some no-heat rated wiring.

Next, I installed the interior light. Note the rust starting to take place.

Access hole for the burners. This made it much easier to replace the burners.  When I installed 4 J boxes, I used a hole saw to cut a large enough opening in the back to access the burners. Furthermore, two set screws were used to secure the burners in place inside the oven. See the next photos for that.

11,000 watts of burner power finally installed.

Building the Door

Cutting the metal for the inside of the doors. Wish I had a brake press / metal shear when I was doing this.

Structural supports for the window getting fabbed up.

Doors being assembled. Used the donor kitchen range window. Just make sure you mark the inside before installing. I forgot to do that and installed the outside on the inside. Over time, the window became foggy and had to replace it.

Door is finished. Time to mount it to the oven.

Door all mounted. I used the donor Kenmore oven door handle

Door hung with 6ft piano / continuous steel hinge. Latches to keep all the warm inside. I also used a 5th caster wheel to support the door weight (not in photos). Even though the hinge was sturdy, there was some sag after mounting. You can see in some of the last photos at the very bottom, with the wheel installed on the lower right side of the oven door.

 

High temp seal going on. I used a wood oven door seal. I used high temp caulk to affix it in these photos, however they quickly began to fall off, so I used sheet metal screws later to keep it in place.

Everything works so far

Finishing it up

Racks all bolted in. Generic hardware store metal racks and 3ft x 4ft grid wall panels. you can use anything, but I suggest getting chrome or bare metal. These were powder coated and over time started to chip and flake off. So don’t use anything with powder coating on them or it will ruin your projects over time. Also I sprayed the inside with high temp POR15 to keep the rust at bay. If you use mild steel, you should paint all those surfaces with high temp oven paint prior to using the oven.

Ready for powder coating. Our first, small kitchen range oven on the right.

Controller #2 came in the mail, had to do some minor rewiring for the new box, & live test #1. The exterior never got above 90º even when the oven was on for hours. So the insulation I used worked pretty well, even though it wasn’t rated for it. I still suggest using the proper insulation.

 

First sets of Centric and BBS wheel faces getting coated.

The key to getting high quality powder coating is the gun and a proper filtered spray booth. Furthermore, we were having contamination issues. Despite keeping everything very clean , we still had issues. Afterwards, we had much higher results with quality once we moved into our commercial location. We started using a proper spray booth and gun, and using this oven. That alone, was a night and day difference in the quality we were producing. In conclusion, this oven build was a massive success.