I started with a rectangle of 3-5 ounce thickness vegetable-tanned leather I had left over from other projects, wet it in water until it was thoroughly soaked, and wrapped it around the broken plastic iPhone case to start shaping it. I pulled it tight around the corners. I cut slits in the leather to make it fit better, figuring that I would cut away a lot of excess leather later after it had dried in shape.
I used thin rubber bands to hold it together while it dried, which took about two days (especially where there were multiple layers).
Once it was dried, I cut back the excess material until it was approximately the right form to allow access to all the buttons and other iPhone controls, and I added segma snaps from Tandy.
The outside of the leather was smooth, and I wanted a bit more gripping ability, so I used my saddlemaker's groover to roughly scrape some grooves in the back of the case:
Since I had initially formed the leather case around the plastic case, the leather case wasn't as close fitting as I wanted. I wet it a bit (not completely soaked this time) and wrapped it around the actual iPhone, and let it dry out again overnight.
Here is the case after I had been using it for a few days and snipping off bits of it to get better access to the screen and reduce the excess leather.
Here it is unfolded. Note that the leather around the corners of the phone has been stretched and formed to fit the curves of the phone, so this isn't a flat piece of leather.
Review of the Prototype
Since this was simply a quick-and-dirty prototype to see if I could make a usable one-piece case, I didn't bother putting any color or finish on it. Once I cut slots and holes for the charger plug, microphones, camera, headphone jack, power button, sound and volume controls, the case was significantly weakened (especially by the slot for the charger). The design held the phone sufficiently well for being carried in my pocket, but I'm not sure I'd feel secure enough to have it hanging from my belt.
For the next try, I won't cut holes for the power button or the volume control rocker switch. If the leather is thin enough, I can push those buttons right through the leather without having to weaken the case as much.
It turned out that the upper snap and strap interfered with the proximity detectors on the iPhone, so the screen would go blank and unresponsive even when I pulled the phone away from my ear. This was a showstopper for the snapped front-opening design.
On to the next prototype!
