A high solids, sprayable, fast drying, ready-mixed setting-type joint compound comprising a blend of a joint compound mixture comprising: joint compound mixture ingredients comprising: calcium sulfate hemihydrate (e.g. US Gypsum's HYDROCAL C-Base), a chelating agent, and water; and an activator mixture, wherein the activator mixture comprises: activator mixture ingredients comprising: inert filler, set accelerator, and water, wherein a weight ratio of joint compound mixture:activator mixture is 1:1 to 100:1, wherein the activator mixture viscosity is the same as the joint compound mixture viscosity plus or minus 50 percent, and wherein the joint compound has about 55 to about 80 wt. % solids and a viscosity of 2,500-28,000 cps.