Assessment of blasted surfaces progress report no. 3

Introduction This report covers work carried out from January - August, 1964. The work has largely consisted of further tests with the Cranfield reflectivity equipment and associated measurements of pull-off strength, but a brief assessment has also been made of an instrument for measuring reflectivity developed by the Paint Research Station. A number of miscellaneous tests are also reported. The final months of the period covered by the report have been spent in the design and construction of a new reflectivity instrument which incorporates features that the previous instruments have shown to be desirable'. Particular topics reported cover the effect of grit size and blasting time, and also a determination of the effect of using light sources of specific colours instead of white light. Much of this work has been done at laboratories and works away from Cranfield to allow external assessment of the reflectivity equipment. A number of miscellaneous tests have also been made covering the use of non-metallic grits and 'Jasonl type hammers for surface preparation, the assessment of sprayed coatings by a simple bend test and the examination of the variation of strength with time of two adhesives to determine whether an adhesive could be used for practical site testing of sprayed coatings