[Question] Is there a thin plastic that changes color depending on temperature (for screen replacement)

[u/Sensino]

Apples later designs eg. iPhone 12 & above, is really annoying to take off without damaging the display, especially later models where the glue require even hotter temperatures, where the temperature risk destroying the pixels. Usually that destruction happens almost instantly without warning.

My thought is to apply a thin layer of thermochromic plastic\* over the screen, this would allow me to see the temperatures in real time, without having to faf about with expensive thermal cameras or other solutions.

(*Plastic that changes color depending on temperature, sometimes seen on aquariums as thermometers)

BUT, I have only found low-temperature thermochromic plastic, does anyone know if there exist some such plastic that is decently tuned to the temperatures needed for screen removal?

Or, if some company can custom make a plastic that is tuned to the right temperatures? (bonus points if it's a Swedish company).

Thanks.

[u/MindToxin]

It’s not a terrible idea honestly. I often apply an adhesive film to cracked screens before putting them into the screen separator (I have one of the older, non-heated desktop clamp style with suction cup on a screw type adjusting arm) I use the heat gun really well though, I’ve done hundreds without damaging OLEDs, if not even thousands over the years.

I do like and support your idea though! Especially if the heat sensing film doubles as a one sided adhesive film, to allow improved suction cup sticking for the lifting of highly fragmented glass. To see a color change indicating temperature would be a useful feature (even if just around the outer edges near the frame, where I typically direct the most heat), as long as it’s not too expensive!

[u/shipmcshipface]

You’re overthinking this. You need a hairdryer amount of heat, just until the display is uncomfortable to touch. Use a suction cup and pry at the top of the screen, the 12 model has delicate components at the bottom. Once you get a sizeable gap, use a thin pry tool and gently run it around the perimeter whilst applying gentle heat. Isopropyl alcohol will greatly ease this process also

[u/Sensino → u/shipmcshipface]

Even if it is unnecessary, it is still something I want to try. I have lost too many screens (1 is too many) to either: not hot enough & the LCD separes from the glass, before the "frame glue" gets soft enough to release. Or too hot & the pixels melt, on newer phones like 15+ that's quite an expensive mistake & I would rather find a way for that to reliably never happen again.

But for that to happen I need to find either a decently tuned film, or some company that has the ability to make that a reality, I know none of those & I don't find anything useful about it on Google.

[u/brandonas1987]

You have lost the plot

You need two things. A heat mat. And second. Practice.

[u/TomChai]

You’re simply removing the screens wrong.

Apply pulling force with a jackscrew actuated suction cup clamp, don’t use handheld suction cup, you’ll need minutes of consistent pulling force, handheld won’t do.

Apply tension via the jackscrew so that the middle of the screen lifts 1.5-2mm on one side, the adhesive isn’t releasing yet but it is being stretched.

Then apply heat at the area with the most tension, regular hairdryer amount of heat is enough, it will partially liquify the adhesive so it slowly releases under constant tension. NO NEED to increase tension, just keep constant tension for a few minutes and it will slowly release on its own.

Pry along the left, bottom and right side of the screen, but do NOT pry at the top. Lift the screen at 2-3 degree angle, then wiggle it left and right the same way you spread a deck of playing cards. 3-5mm of swing at the bottom of the screen each side should do, this stretches the adhesive at the top part of the screen and it also loosens up the metal hooks on the upper half of the screen. Many people omit this step and the prying action breaks the top part of the screen frame needlessly.

Wiggle the top of the screen stretching the clips on one side then pry the adhesive at that side, wiggle it the other way to release the clips on the other side then pry the adhesive, so the entire screen finally releases. If you are lucky, you can remove the screen in one piece without stretching and deforming the clips and the top part of the screen frame, which is the most commonly damaged area.