ASK THE EXPERTS
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I am having a new boat built. Should I have the hull shot-blasted before applying two-pack epoxy blacking? BILLY BOYLE
TONY REPLIES… It depends on exactly what two-pack epoxy blacking the builder will be using (so check the manufacturer’s instructions) and what steel the hull builder used. Most steel used in UK boat construction is hot rolled, creating a film of ‘mill scale’ on the surface. When water gets under mill scale and rusting starts, the mill scale falls off together with the hull blacking, so blasting is usually recommended to remove the scale.
However, you can get steel that’s been treated to remove the scale before delivery, in which case, if there was no rust and any preservative oil was removed, blasting might not be needed.