How to distinguish high quality and inferior aluminum truss

First, high-quality aluminum truss welding, accurate dimensions, and does not appear unacceptable or truss and accessories.

Inferior aluminum truss welding rough, irregular shapes, different sizes, and unoperable welding.

Second, the high-quality aluminum truss is immersed in the acid solution, the surface is bright silver, novel and elegant, and lustrous.

The poor truss is not immersed in an acid, the surface is no shiny and earth gray, just like an old antique.