I need to make a small inner tube for a project. I cannot get a custom one made at a smaller size. The length of the tubing should be just 110 mm. i have to use a valve that is made of rubber, plastic or stainless steel ( last option) . The tube goes into a magnet, so i have to be careful that the valve i use must not be iron or any attracting materials. Is there a possibility to make it at home.