I am powder coating over sterling silver (will switch to Copper) and
notice that many times my cast silver gets these air bubbles in the
paint. when you powder coat, it only goes into the oven at
350degrees for a half hour or so, and the temperature to 350
increases really slowly. The cast pieces are pre-baked, to help
release any trapped gases in the casting and to prevent these air
vents before the baked on paint process. But nevertheless it happens
and ruins about a third of each batch I paint.
I am told the air bubbles occur from the trapped gases in cast
metal, that release during the firing, or oven baking, of the powder
coating process. Is there a way to prevent this in the casting,
and/or are certain metals more prone to this than others?
thanks for any input!