I can't think off the top of my head if there is an acceptance criteria but I know that if 180 microns is at or above the coating thickness required for the first coat, you will have peaks of metal exposed through the first coat. The protruding metal exposed to the environment will rust which can cause adherence issues with an overcoat.

Of course there must be a bloody tolerance on surface blasting and it should even differentiate between shot, grit, and mix of both blasting cycles.
High peak, mean of 10 peak, etc over a small surface should be measured if you can't afford scanning the entire blasted surface to check its quality before applying coating.
If the surface preparation is crap, your coating won't last.
Remember: garbage in(side), garbage out(side).

* Finding a solution is great * Knowing how to implement it is fantastic * Believing it is the only one and best is naive ?

You're 80% over the upper acceptance limit, so it failed, period. There's no amount of reasonable tolerance that would bring you into compliance

TTFN (ta ta for now)
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