Tl-1223 tapes with engineering critical current densities, (E-J/sub c/) values of 2500 Acm/sup -2/ can be routinely fabricated but the magnetic field properties are poor due to weak link effects. We have developed a partial melt processing route which results in increased grain growth with greater potential for achieving grain alignment. We have investigated the effect of Tl-1223 phase composition on the melt process and found that Bi substitutions lead to an increased grain size in tapes made using unreacted powder but a decrease in grain growth in tapes made with reacted powder.