What grade of carborundum is recommended for getting a high polish on terrazzo slabs?
No. 120. The overall degree of polish that can be given to a terrazzo slab is however greatly influenced by the fact that the marble stores of the aggregate can be much more highly polished than the hardened cement mortar. Thus it is advisable during construction to grade the aggregate so that it contains as great a proportion of large pieces, with a maximum size of l/2 inch, as possible. A final polish with a carborundum finer than No. 120 will improve the polish still further, but this must be delayed, for a properly cured slab, until some 20 days after placing.