In case you hadn't heard by now, the iPhone 5 is hard to come by right now. Apple (NASDAQ:AAPL) simply can't make enough of them to satiate massive demand for the device. New orders placed on its web site are currently being quoted shipping times of three to four weeks, and heading down to a local retail store is hit or miss. It looks like those in-cell touch display panels aren't the only potential bottleneck hindering the iPhone 5.

According to a recent Bloomberg report, Apple's choice to utilize aluminum for the primary unibody chassis is another culprit contributing to the shortages. Using the same type of aluminum that's used in its laptops is one key facilitator to the iPhone 5 being so thin and light. The material is lighter than stainless steel, used for the antenna in the iPhone 4 and iPhone 4S, but is softer so it scratches more easily.

Source: Apple.

Throughout the production process, there are a slew of steps that could result in damage and scratches to the chassis, meaning they won't meet the heightened quality standards that Apple is enforcing in light of user complaints that they're receiving pre-damaged iPhone 5 units. Despite marketing chief Phil Schiller downplaying the issue in an email response to a customer, Apple's now putting pressure on contract manufacturer Foxconn and raising quality standards.

Jacob Huang, a professor of materials engineering, told Bloomberg that a hardware maker could even use magnesium, which is lighter than aluminum, but also softer and even easier to scratch. Microsoft (NASDAQ:MSFT) should be paying attention there, since its new Surface tablet is built out of magnesium. Not only is the software giant reportedly facing low production yields related to the material, but it could also end up on the receiving end of user complaints related to scratching.

If there's one thing Apple doesn't need right now, it's more possible iPhone 5 bottlenecks. But considering the relatively short-term nature of the shortages, it's still a buy in my book.