Summary for prep for powder coating Discussion
Prep for powder coating black iron pipe is the central issue here: Bob Dixson says the pipe has a rough black lacquer-type mill finish, and after using a carbon-steel prep routine, one small area bubbled and stayed bare after cure. He asks how to prep the pipe without sandblasting, since the job budget does not allow outside blasting. Bill William Doherty replies that there is not enough information to give a complete process, but warns that most lacquer finishes will not tolerate powder-coat cure schedules. He says the lacquer would normally need to be completely removed by abrasive or chemical methods before a phosphate pre-treatment and powder application. He also asks for more detail on the normal preparatory process if further help is needed.
Q. We are trying to powder coat black iron pipe with a black lacquer type finish on it. We prepped a few pieces like we do carbon steel. When it came out of the oven there was a 1″ X 1/2″ spot that appeared to bubble a little and no powder on it. The rest of the pipe looks good. The lacquer finish on the pipe from the mill is rough by nature. My question is how do we prep the pipe? We don’t sandblast or have money in the job to get it sandblasted outside.
Bob Dixson
– Anderson, South Carolina
September 29, 2015
September 30, 2015
A. Like to help but insufficient info provided.
What is your normal preparatory process?
Most Lacquer finishes will not tolerate Powder Cure Schedules.
Normally, the lacquer would need to be totally removed by either abrasive or chemical means before a phosphate pre-treat and powder application process.
Perhaps if you could give more detail we could further assist.
Hope this helps.
Regards,
Bill
William Doherty
Trainer – Newcastle, NSW Australia