You are the NACE Inspector on a job where NACE No.2/SSPC - SP 10 has been specified. You are finding the Contractor is leaving mill scale on the surface and as a result you have been rejecting the blast. The Contractor is very upset and has told you that the standard permits up to 5% of the mill scale to remain and still be in compliance with the standard.
A single application coating film has measured dry film thickness (DFT) between 4 and 5 mils (between 100 and 125 microns). The volume solids of the coating immediately before application were 67%. What wet film thickness (WFT) was applied?