Internal Plastic Coating Internal Plastic Coating of Drill Pipe improves the performance and life of the drill pipe. The Drill Pipe is thermal cleaned and the internal surface is blasted with grit for a good anchor pattern preparatory to Coating. A two stage application of phenolic / epoxy liquid coatings is sprayed on to the internal surface of the drill pipe in a controlled manner and thermal cured at each stage. This ensures uniform coating thickness and Quality throughout the length of the Drill Pipe. The finished Drill Pipe is externally coated with rust preventive varnish, attached with Thread Protectors and Skid Bundled with utmost care.