CGC and SYNKO premium setting type compounds are the professional's choice of compounds for interior gypsum panels and exterior gypsum ceiling boards. CGC's chemically setting compounds rapidly harden (approx. 90 minutes, 45 minutes, 20 minutes) and have low shrinkage allowing for same day joint finishing. These products feature exceptional bond strength (virtually unaffected by humidity) and are ideal for heavy fills (shrinkage crack resistance). In addition, CGC and SYNKO setting-type compounds can be used for filling voids in interior concrete ceilings and above-grade concrete surfaces. CGC and SYNKO premium setting type compounds should be your choice for a professional finish.