Problem Solving Forum
June 8 - June 12, 2020
What is the remedial action if a blaster produces too high a surface profile for the required primer thickness?
Dong Duy of Alpha-ECC Vietnam on
June 14, 2020:
I do not really get the point. Only a few coatings ...read more I do not really get the point. Only a few coatings require the restricted surface profile, such as IOZ or some powder coatings. The remainder coatings, most of them organic, do not have problems with covering the excessive surface profile. Please note that DFT is specified from the highest peaks to gage's probe. So as long as you calibrate DFT gage on the bare blasted surface (which means the DFT shall be calculated from the highest peaks), you still get adequate paint volume to cover peaks. Calibrating your DFT gauge with a smooth plate leads to the wrong DFT measurement, which insufficiently covers peaks, and pinpoint rusting may occur.
Michael Symbolik of MIK industrial on
June 11, 2020:
Press lighter on the profile tape & get rid of ...read more Press lighter on the profile tape & get rid of the digital profiler ;) lol Seriously , this spec is overlooked a lot at bidding and could be a costly mistake. Anyway , grit size, air pressure and technique will all have a part in this, but, mainly, it's the coarseness of grit ... #40 ... #80 ... etc., that counts most.
Jaime Marcos of Profesional independiente on
June 10, 2020:
Increase the dry film thickness (microns), or chan ...read more Increase the dry film thickness (microns), or change the primer. If it was a small surface, conduct mechanical sanding to reduce the ridges of roughness. Before starting the blasting work, it is necessary to select the appropriate abrasive to achieve the required roughness.
Mike Makela of Sunstate Coatings Inc. on
June 8, 2020:
Reblast with the proper abrasive to reduce the pre ...read more Reblast with the proper abrasive to reduce the previous profile.
Gavin Gooden of BlastOne on
June 8, 2020:
I have found this issue where the surface had exis ...read more I have found this issue where the surface had existing excess profile from a previous job where a large steel grit particle size was used. We have effectively whip-blasted the surface again with an 80# or 120# garnet and it has reduced the profile by about 1 mil. See the full article. https://www.blastone.com/us/resources-training/tips-of-the-trade/significantly-reducing-surface-profile