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.