An enclosure and a method for forming an enclosure are disclosed. The enclosure may be formed from metal, such as aluminum, and further include a non-metal portion allowing for transmission and receipt of electromagnetic waves. The non-metal portion may be interlocked to the enclosure and in particular, to a region within the enclosure including a first material having a relatively high strength and stiffness compared to the non-metal portion. Interlocking means may include forming dovetail cuts into the enclosure to receive the non-metal portion, a hole or cavity drilled into the enclosure which includes internal threads, and a rod inserted into the first material to provide a tension to the non-metal portion. Methods of assembling internal components using anodization are also disclosed.