It may seem obvious, but it bears repeating: the powder coating oven runs hot.
More precisely, the powder coating oven typically reaches around 400 degrees Fahrenheit. This is important, because it directly affects the types of parts we can powder coat.
For instance, I frequently get requests to powder coat parts that aren’t 100% metal: assembled wheels, miscellaneous car parts with rubber gaskets, patio furniture with plastic pieces, etc.
The melting point of most commonly-used plastics is between 212 – 255 degrees Fahrenheit, and most common rubbers will start to melt at 350 degrees and above, meaning that rubber and plastic cannot go into the powder coating oven.
This is why I strongly recommend disassembling parts as much as possible. If all plastic and rubber attachments are removed, we can powder coat the metal pieces, and reassemble everything after curing. Parts that can’t be disassembled (and aren’t 100% metal) will have to be liquid coated.
Plastic and rubber aren’t the only materials that melt in the oven. We also frequently run into issues with grease, particularly in small parts, or enclosed areas that we can’t access with blasting. As the oven heats up, the grease liquefies and runs, ruining the powder coating finish.
We’ve been doing this a long time, so we’re often able to predict which parts will release grease, even if it’s not immediately visible at room temperature. If there’s a risk of grease, we’ll take measures to avoid damage – i.e., not powder coating certain areas, etc. Sometimes, we’ll push our luck to make a customer happy, and it always ends the same way: with ruined powder coating, and the need to start all over.
The moral of the story is that if you want something powder coated, it must be entirely metal. Any plastic, rubber, wood, and other non-metal pieces must be removed. Additionally, the powder coating process will go much more smoothly if all grease is dealt with before the part is coated and cured.