Powder Coating Over Hot Dip Galvanizing

Powder coating over hot dip galvanizing is an excellent combination, giving very long life to the structure.  Each coating helps the other last much longer than it if were used alone.  However, improper powder coating techniques can result in defects known as “pin-holing” or “cratering.”  These are small but unsightly pin holes or craters in the surface of the powder coating.

These pin holes are absolutely the most common defect in powder coating over hot dip galvanizing.  The following procedure was established to effectively eliminate the possibility of these defects.  It is considered to be substantially more reliable than the common use of “out-gassing” primers.

All procedures MUST be done on the same day!!!

1)    Pre-Bake at a temperature higher than the final curing bake

2)    Sweep blast all surfaces

3)    Apply powder coating per manufacturer’s specifications

4)    Bake to cure at a temperature lower than the pre-bake