As construction labor costs soar, architects, engineers, and builders are looking more determinedly than ever for economical ways to satisfy owner requirements. A key fact in the economy of tilt-up construction is utilization of the floor slab as a casting area for the tilt-up panels. What means can be employed to develop the full strength of the concrete and assure separation between the floor slab and the tilt-up panel? Numerous compounds for curing and parting have been developed. One of the first cure and bond breakers was a wax-based material which provided the best water-retention, was an excellent parting compound and was the cheapest material available. Why then is it so seldom used? Because selection of a cure and bond breaker is usually determined by other properties beneficial to both the contractor and owner. Here are some of the factors which should be taken into consideration: is the material produced by a reliable manufacturer? Is it a dependable bond breaker? Is it a good curing agent? Can the panels be painted? Does the panel look clean? Can a floor hardener such as a magnesium or zinc fluosilicate be used over the cured floor? Can resilient tile be applied over the compound used? Does the compound dry rapidly? Does the compound spray easily? And finally, is it economical? Cure coat should be applied to the hard-troweled surface immediately after the final hard troweling. In hot, windy weather, with low relative humidity, one-half hour cannot be considered immediately. Timing is more critical on this coat than on the bond breaker coat. All the compounds previously mentioned contain a petroleum solvent. As oil floats on water, the petroleum solvent and dispersed solids must be held up by moisture present in the concrete at the time of application. If moisture is not present at the time of application, the compound may be bolted into the concrete leaving no tilt-up panel. In extremely hot weather, it may be desirous to fog-spray the slab with water immediately ahead of the cure and bond breaker application. The bond breaker coat should be applied just prior to placement of reinforcing steel, using two light coats applied evenly at 600 square feet per gallon.