blast and paint profiles
blast and paint profiles
(OP)
I am completely ignorant to blasting and paint profiles, by my choice I might add. Now, however, it has become part of my job to see that our coatings are correct.
I need information on the following:
If I read a blast profile of 3.7, does that not mean that we would need DFT paint mils of around 4.0 for sufficient protection?
The only specs I have are a SP-6 prep with 2-3 mils of Carbozinc. I understand that your blast profile cannot exceed your primer and/or cannot exceed 1/3 of your total DFT. Is that correct?
Thanks!
I need information on the following:
If I read a blast profile of 3.7, does that not mean that we would need DFT paint mils of around 4.0 for sufficient protection?
The only specs I have are a SP-6 prep with 2-3 mils of Carbozinc. I understand that your blast profile cannot exceed your primer and/or cannot exceed 1/3 of your total DFT. Is that correct?
Thanks!





RE: blast and paint profiles
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: blast and paint profiles
RE: blast and paint profiles
Grade of Surface Cleanliness ISO 8501-1 SSPC
White metal Sa 3 SP-5
Near-white metal Sa 2½ SP-10
Sweep blast cleaning - SP-7
Solvent cleaning - SP-1
Power tool cleaning St 3 SP-3
Power tool cleaning to bare metal - SP-11
Water jetting (ISO 8501-4) Wa 2½ SP-12
Wet abrasive blasting - VIS 5
RE: blast and paint profiles
However - the deeper the profile, the higher "rogue peaks" you will have. These are scattered "end of the bell curve" peaks which can lead to pinpoint rusting, even with 2-3 mils of coating over top of the nominal peak height.
I don't like to have a blast profile deeper than my DFT due to the rogue peak concern.
RE: blast and paint profiles
If the profile is too deep and the inspector/engineer wants to prevent painting, a good compromise is usually that if the profile is 1.0 mils - 1.5 mils deeper than specified or that is called for in the primer's product data sheets, the contractor shall add an extra 1.0 mils - 1.5 mils of primer.
Is 3.7 mils the average of a few profiles? Are you taking anchor profiles with testex tape and a micrometer?
3.7 mils will work fine with Carbozinc 859. I do not represent Carboline, but I'm sure your rep will send you a letter to that effect if requested.
What type of DFT Gauge are you using? Type 1 or Type 2?
NACE Certified Level 3 Coating Inspector
8 Years of Painting Inspection Experience