Powder Coating at The MakerBarn

George CarlsonBuild Log, Making, News, Tools

With the completion of the downdraft table/powder coating booth, and the acquisition of a new oven, we now have the facility to do powder coating. Powder coating is a process where a dry powder-like paint is applied to a metal piece using electrostatic attraction. The piece is then baked in an oven, causing the powder to melt then polymerize into a very durable coating.

Here’s an example. This is a butterfly cut from a piece of 1/4″ steel using a plasma cutter. The butterfly was cleaned and then blasted in the abrasive blaster to remove the mill scale and give a nice even surface for the power coating to adhere to. After this point in the process you should use gloves to protect the clean object from oils on your skin. Oils on the surface of the part are not good for the powder coating.

 

The powder is then poured into the container for the gun. The powder has the consistency of no-sift flour. It is a good idea to do this in the spray booth with the fan running. This will help contain any spills that may occur.

 

Using air, the powder is blown unto the steel part. There are small electrodes on the spray gun that give the powder an electrostatic charge. The object being coated is grounded, which causes the powder to be attracted to the part. Sometimes it can be difficult to get the powder into small areas. Shaking the gun a bit can help produce a heavier blast to these areas, getting past the small “force field” that occurs.

 

After thoroughly coating the part, it is hung in the oven to bake at 380 degrees for 20 minutes.

 

After removing the object from the oven and allowing it to cool, the finish is completely cured. No solvents are used in this process, so there is no smell or disposal of hazardous solvents. In this example, a blue high-gloss coating was used. There are hundreds of colors and finish types available. eBay is a good place to shop for various types of powder coating supplies.

 

Almost any metal object can be powder coated. Keep in mind that the 380 degree oven can melt plastic, char wood, and destroy rare-earth magnets.