In our continuing efforts to improve our  quality and service, this section has been set up as a guideline for incoming items to be coated.  Some of the items in the proceeding list, are understandably avoidable in specific cases, however attention to all of these details can only affect the quality of your valuable parts in a positive manner.

1) PACKAGING

Please ensure that the packaging, containers, or skids that you supply with your product provides proper protection against damage.

Note: The material will be repackaged in the packaging containers you supply.  Therefore, packages must provide suitable protection against damage to the material as well as the coated finish.

2) MARKERS

All materials to be coated should be free of inks (such as those from writing utensils like markers).  These inks can show through on the finished coating (especially when the parts are coated in lighter colors).

3) WELD SPATTER

All welds should be clean and the surrounding area is to be free of weld spatter whenever possible.

The heat involved can not only change substrate properties, but it can also incorporate contaminants into the part surface (our pre-treatment process is only designed for the removal of surface contaminants, and is not a suitable substitute for mechanical cleaning). This will invariably compromise the integrity of the final powder coating.  In extreme cases it may be manifested by bare spots and pinholes.

4) PACKAGING DEBRIS

All parts to be coated should be free of packaging materials and shipping debris.

While our loaders inspect parts as they are hung on the line, certain problems have arisen.  The major offender has been clear tape (of various types and sizes)  as it is nearly impossible to detect, especially in larger orders.  The end result of this melted tape on the substrate is always complete coating failure (ex. zero powder adhesion).

5) OXIDATION

Any type of oxidation (ex. rust, white rust etc) can only affect the final product's quality in a negative manner. 

Our pre-treatment process cannot remove oxides, and if a substrate is severely corroded (or has been lying around a shop for an extended period) the end product will inevitably have less corrosion resistance and a lower quality finish.  The only solution is mechanical refinishing of the substrate.

6) GALVANIZED & ZINC SUBSTRATES

Poor quality of galvanized and zinc coatings adversely affects the final product and in no way is The Powder Mill liable for lesser coating quality on these substrates.  Ultimately, the customer is responsible for the condition of the substrate before it arrives at our site.

7) DRAINAGE

All parts fabricated from tubing should have drain holes, as powder will not adhere to a tube with water trapped inside.

Also, all parts must be hung on the line, and as such the configuration must be considered each time a new part is introduced to our process.  The Powder Mill will inform the customer of any special requirements when the purchase order is placed.

8) PREPARATION OF YOUR PRODUCT

The coated parts are cured in an oven at up to 450 degrees F, for up to 30 minutes or more.  Therefore, any part of your project that cannot withstand the temperature and time exposure must be removed before coating.

Due to the fact that powder adheres electro-statically, it must be applied to a very clean surface.  It will not cling sufficiently well to old paint, primer, most metal fillers and rust.  Chemical stripping,  bead blasting and or mechanical cleaning of the surface is recommended (sand blasting with coarse media can leave a rough textured surface that may show through the finish and in some cases it can cause gassing which may result in pin holes).

When mechanical cleaning (blasting) is required a "white metal blast" grade is mandatory.

View additional information on surface finish standards at and view cleaning recommendations at

To learn more about "Eliminating Crevice Corrosion" check out Powder Coating Magazine's recommendations

To Learn more about Powder Coating Metal Substrates check out Powder Coating Magazine's article titled "Factors affecting the Service Life Organic Coatings on Metal Substrates" which appeared in the October 2004 issue.