Casting Ring Liners II : Cushioning Effect of Waterproofed Casting Ring Liners on the Setting Expansion of Investment Material

Abstract

The cushioning effects of waterproofed casting ring liners on the setting expansion of investment materials were evaluated by cushioning ability in 15 waterproofed ceramic liners (A:rockwool type, B:ceramic fiber low temperature type, C:ceramic fiber standard type, D:ceramic fiber low temperatures tandard type, E:kaolin type) and 3 waterproofed asbestos ribbons (AS). Setting expansion was measured using a metal mould and waterproofed liners were seated inside the sliding frame for 120 min. Cushioning effects were calculated by the difference between the setting expansion without liner and the setting expansion with liner. The cushioning effect of waterproofed liners except one product of AS increased with time. Waterproofing treatment improved cushioning effect of two products of A and one product of D, where water sorption in the dry liner was high. Waterproofing treatment changed the cushioning effect of one product of C and one product of AS for the worse. The other thirteen liners slightly changed the cushioning effect.