Loctite MR 2000 Putty Extreme temperature, silicic acid, water-based repair putty that withstands environments up to 2,000 °F (1,000 °C). Is a silver gray, extreme temperature, silicic acid, water-based repair putty that withstands environments up to 2,000 °F (1,000 °C). It is an environmentally non-toxic, water-based compound which is non-flammable and contains no solvents or volatile compounds. Loctite MR 2000 Putty can also be used in automotive exhaust applications, in headers, manifolds, catalytic converters and exhaust ports.