Krack Kote makes invisible, permanent repairs to cracked walls and ceilings in under an hour This specially formulated acrylic emulsion is used with a fine polyester mesh to bridge over cracks in plaster and drywall. The product remains flexible even after it dries, preventing the cracks from resurfacing. The material won't shrink and requires no sanding. Make seamless repairs that won't reopen like other fillers and putties do.