is the requirment 100% visual?
If it is its gotta be blasted.
Then repainted.
If the shop is spanked over this they will pay more attention to Quality control requirments next time.
As for painting Look into sspc for guidence, along with the paints manufacturers recomendation data sheet.(dont brush it)check the data sheet.
http://www.tnemec.com/resources/product/PDS/90-97.pdfThis may help you decide….
I worked at a weld/paint shop for 5 years, and I cannot count the times that Id come down from the office
And see them moving product into the paint booth and already spraying (endless battle between production and quality control).
Id move ahead of the painter and started a visual inspection , needless to say the soap stone was marking the undercut, porosity, lof. Ect (trust me a weld looks a lot different after blasting you can see everything).
But when I looked at what was painted it was not visible.
MDK