Pinholes in powdercoating

March 4, 2008

Pinholes in powdercoating on galvanized steel seem to be a poorly explained problem. Some claim its gas emerging from the zinc (hence the name sometimes used - gassing), but what gas? and how did it get there?
Some say its due to pretreatment liquids penetrating the zinc (really?)
Some use a "degassing " procedure, involving heating the steel to curing temp between pretareatment and powder application, cooling again before spraying.
Some use "anti-gassing" powders that skin over slower, allowing the gas to escape.

What do you think? What causes it? Why do some steels exhibit it more than others? Why does galvanneal show it worse that regular hot dip?

Geoff Crowley
galvanizing &
powder coating shop
Glasgow, Scotland

April 18, 2008

Dear Mr. Geoff Crowley
here I am giving my experience on degassing problem when we powder coat on different types of steel or same MS steel(crca)of two difference batches.
this degassing problem is connected with the metal composition.

JAGMAL SINGH
- Gurgaon, Haryana, India