Australian customer purchase powder coating pre galvanized steel square tube. After customers receives the goods for the first time . Customer tests adhesive strength between the powder and the surface of the square tube .Customers test powder and square surface adhesion is small . We have meetings with customers to discuss this problem and we do tests all the time . we polished the surface of the square tube . Send the polished square tube to the heating furnace for heating . We tests all the time and discuss with customer all the time . We keep finding ways . After many tests, the final customer is very satisfied with the products. Now customer purchase a large number of products from factory every month .