In an interesting twist to Scuffgate, Apple’s marketing boss Phil Schiller has admitted that the iPhone 5’s susceptibility to scuffing is… “normal.” Furthermore, it would seem that Apple is fully aware that the iPhone 5 is easy to scuff — and yet it knowingly proceeded to manufacture (and sell) record breaking numbers of the new device.

Phil Schiller’s comments come from an email response to a customer, who had contacted the vice president to ask about some “scuffs, scratches and marks” on the chamfered edge that surrounds the phone. Schiller’s reply, in full, is below:

Any aluminum product may scratch or chip with use, exposing its natural silver color. That is normal.

A little unbelievably, this seems to be the only official Scuffgate response from Apple. The email is very short (17 words!), so we’re loathe to read too much into it — but it does seem to give off a feeling of condescension, or perhaps nonchalance. The original email also asks Schiller if there is any plan to fix the scuffing issue, but Schiller ignores that in his response, which could well mean that Apple doesn’t plan to replace or recall damaged iPhone 5s.

Aluminium is soft

In our original Scuffgate story we analyzed the iPhone 5’s anodized chassis, as that seemed to be the underlying cause of the scuffs and scratches. Anodization can significantly add to aluminium’s durability, but only if it’s done properly — and it would seem that Apple either forgot to seal the anodized coating, or it simply didn’t make the anodized layer thick enough to prevent scratching.

Schiller’s response complicates things, as it suggests that the aluminium itself is the underlying cause. It’s possible that Schiller, being a marketing guy, doesn’t understand the interplay of aluminium and anodization on the iPhone 5’s back and sides — but really, if that’s the case, should he really be replying to scuff-related emails in an official capacity? Still, for the sake of argument, let’s assume that the scuffing is actually caused by some intrinsic failure of aluminium.

Apple chose aluminium for the iPhone 5 chassis because it’s a lot lighter than stainless steel, which made up the bulk of the iPhone 4 and 4S chassis. Per cubic meter, aluminium is a third of the weight of stainless steel (2600kg vs. 8000kg). In exchange, though, aluminium is much softer than steel — it is quite easy to bend or dent aluminium with minor pressure, while steel is very tough. Aluminium is so much lighter than steel that the usual solution is to simply use a thicker layer for more strength — but this doesn’t make it any harder. A fat block of butter is no harder to dent than a thin block of butter.

Still, I don’t see how the inherent softness of aluminium makes the iPhone 5’s back and sides more likely to “scratch or chip.” Schiller must be referring to the fact that anodization simply isn’t strong enough to withstand everyday use. We know this isn’t the case, though, as anodized aluminium is very well understood and used in a massive gamut of applications — including military, where the anodized coating certainly doesn’t just scratch off.

Lighter, but at what cost?

This poses an interesting question, though: If Apple knew that the iPhone 5’s anodized aluminium was easily scuffed, why didn’t it use stainless steel instead? The obvious answer is weight; the iPhone 5 is some 20 grams lighter than the iPhone 4S, most of which probably stems from the aluminium chassis. It could also be an aesthetic design decision: Maybe Jony Ive wanted an anodized finish, and so aluminium had to be used.

Schiller’s email also doesn’t explain one of the most puzzling facets of Scuffgate, too: The fact that consumers are receiving devices that are already scuffed, straight out of the box. We previously speculated that the damage was being caused at the production line, but we’ve also come up with another possibility: Apple might be unboxing iPhone 5s, applying some kind of firmware update, and then reboxing them before dispatch to customers. This is actually fairly common in the high-tech world, where thousands or millions of devices have already been built — but then a software bug is found and must be fixed before public release.

We’re still just theorizing, though. Hopefully Apple is building up to an official, longer-than-17-word response, so that we can find out what is actually going on.

Now read: Scuffgate: Will Apple have to recall the iPhone 5? and How hackers will jailbreak the iPhone 5

[Image credit: Phonedog]