Bicycle Mechanics - Frame prep before powdercoating

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View Full Version : Frame prep before powdercoating


San Rensho
05-10-08, 06:14 PM
I had my frame powdercoated about 9 months ago and I just noticed there is a nice long line of rust bubbling up from under the powdercoat on the underside of the top tube. I'm assuming the powdercoater didn't sandblast it adequately or otherwise didn't prep the surface. Does that sound right?

Is the solution to sandblast (or bead blast), then apply a phosphoric acid based etch and then put powdercoat over that? If not, any recommendations so rust doesn't come through.

I'm going to go back to the powdercoater to ask him to do it again and I want to make sure he gets it right this time.


Servo888
05-10-08, 06:41 PM
Is the solution to sandblast (or bead blast), then apply a phosphoric acid based etch and then put powdercoat over that? If not, any recommendations so rust doesn't come through.

I believe oxalic acid is preferred over phosphoric acid for rust removal.