: I am searching a product to repair : little holes in fine copper pipes : without using sources of heat. : It is a heatchanger of a warm water circuit. : Sorry for my bad EnglishBefore you bother to repair these holes you should ask yuorself WHAT CAUSED IT? you had better check the velocity of the water traveling through this piping. These holes sound like an Erosion problem OR very acidic water. CALL A professional good Luck