Apps, R. L.
Description:
Mild steel surfaces that are to be protected by aluminium or
zinc spray coatings are generally prepared by blasting with chilled
iron angular grit. Previous work1had shown that a relationship
exists between the grit blasting conditions (at least in terms of
blasting angle and grit condition), the reflectivity of the blasted
surface and the bond strength of a spray coating of aluminium on the
blasted surface. An instrument has been developed that assesses the
suitability of a blasted surface for subsequent spraying by measuring
the reflectivity and has proved reasonably successful under laboratory
conditions. The present need is to ascertain the performance of this
reflectivity meter under shop and site conditions. The opportunity
to carry out such tests at H.M. Dockyard, Devonport, was offered by the
Ministry of Defence and a series of tests was made on 16th June, 1965.