I have a stove pipe which I thought was galvanised. 5mm thick and 110 dia. I thought it was a lampost but maybe not. You can see from where it has been scored and cut through that there is a coating on it.
My god, what a coating it is! I have tried battery acid, phosphoric acid too. Left overnight it will not touch it. There is no scale/shade effect like galve. It has a dull solder look.
I am rasping the coating off slowly to steel. You can feel the softer coating when filing and then the file sliding more as you hit the steel below. I wondered if the pipe had been coated in malleable iron?
My god, what a coating it is! I have tried battery acid, phosphoric acid too. Left overnight it will not touch it. There is no scale/shade effect like galve. It has a dull solder look.
I am rasping the coating off slowly to steel. You can feel the softer coating when filing and then the file sliding more as you hit the steel below. I wondered if the pipe had been coated in malleable iron?