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Challenge: Most non-metallic materials are without the needed electric conductivity to support the electrostatic powder coating process.
Solution: wash the object with water to provide temporary surface conductivity prior to coating.

Step 1:

Prepare the objects to be powder-coated. In my case, I cut big numerical number patterns from a wood board as well as from a laminate floor panel using a scroll saw. They are for replacing my older & smaller address numbers above my garage door.

Step 2:

Bake the objects in an oven at the temperature specified by the powder material (400 degree F for my case), which is to expel the internal moisture, and to verify that the objects can survive the elevated baking temperature

Step 3:

Sandblast the objects’ surfaces, which is to remove debris & water-repelling coating. The picture above shows an object not sandblasted before coating, with poor powder coverage. The same object’s surfaces were then sandblasted with much better outcome.

Step 4:

Wash the object using tri-sodium phosphate (TSP) cleaning agent as shown in the picture above. Wash off the agent by tap water. Then, apply acetone on the surfaces to further remove grease. Please put on gloves to protect your skin.

Step 5:

Wash all surfaces thoroughly with water

Step 6:

Shake off excessive water from the object. The surface should be wet but not dripping.

Step 7:

Powder-coat the object before the surfaces dries out. If some spots dry out, wash the object in water again. The picture above shows the improved result.