Cracked outer glass on a Galaxy S4.
I've repaired quite a few phones with cracked outer glass, and this one went smoother than I could have ever expected.
I've used a heat gun (and a butane torch in a pinch) several times, but I'm always worried about overheating the display. The first time I used a heat gun I melted the digitizer...
This time I used the iOpener.
I was skeptical as !&&* to be honest, I didn't think it was going to work at all.
It took a few heating cycles to get temperature right with my wattage microwave, but it was easy enough. I use an infrared non-contact thermometer to check temps. (which I highly recommend) They're under $20 on sale at Harbor Freight.
I heated up around the edges first (you can do half the phone at a time with the iOpener)
I use Molybdenum wire, and usually I have to stop and re-heat the display a half dozen times. I just laid the iOpener down the middle of the phone to keep the display warm while pulling the wire through. It was great, I didn't have to stop and re-heat the display at all.
It normally takes me about 45 minutes to separate the glass. With the iOpener, I was able to do it in less than half that.
I think I'm going to have to order a second one so I can lay them side-by-side and heat the entire display at once.
DO NOT pry the glass up as the teardowns here suggest. That only works if the glass is intact. If there are any cracks at all in the glass you'll break the display/digitizer when you reach the crack as it relieves tension.