I'd like to chime in on this as someone who has managed to do this process successfully on a number of occasions. I've gotten good enough at it that I've taken on helping other people repair their phones for a fee, and am contemplating on just having an ad out there as side income for myself, so here goes.
The first thing I usually do, is with cracked displays, is to layer the top with packing tape, just to make sure that the shards of glass don't go anywhere.
From there, I use a heat gun set at very low heat and heat the phone evenly, moving around for about 30 seconds (do not stay at one spot, keep moving, either in a zig zag or circular motion. The display should be hot, but not overly hot till it burns you. All you're doing is just loosening the adhesive a little.
Start by lifting up the glass from the top edge of the phone, where the earpiece is, and slowly and gently try and lift it up. I use plastic phone opening tools as well as spudges. It should give way relatively easily with light pressure. If it gets difficult, again with low heat, run the heat gun over the next effective area of lifting. I do not recommend metal tools as they can and WILL (from experience) damage the LCD below if you're not careful.
Slowly and gently make your way down the phone to the capacitive buttons, and if you hit little shards of glass, be patient with them. It's patience that will get you your screen replaced hitch free.
Once you get the display edges off, don't get too happy and rip the rest off, because the capacitive buttons are glued onto the display as well, with adhesive. Slowly heat up that area as well, and I recommend this time, with a pair of thin long metal forceps, go in and slowly peel it off the glass
Once you have that off, you can easily separate the glass from the body, and from there what I do is I clean up the body and the display with isopropyl alcohol, to get the remaining glue residue off the display, and prep it for a new pane of glass to go over. It is at this stage that you should work in a dust free room, or at least no AC/ no FAN. Those are my rules anyway.
This is the part that I highly recommend doing, which is fully disassembling the phone, removing all the internal components until you're left with just the inner body and the outer frame. What I do is that I snap the inner body into the outer body, free of any of the internal components (cameras, sensors, anything that you can remove), such that any excess display glue will not seep into them and damage the components (again, I've had this happen to me)
If the replacement glass that you bought does not come with replacement adhesives for the body (not for the screen), then what I suggest you use, (which I use as well) is a combination of 1mm or 2mm, 3M 9448 Tape for Electricals. Normal tape is not nearly as adhesive or thin enough for the job.
After having done so, this is the part where unless you have an autoclave unit lying around, you're going to be using LOCA (Liquid Optical Clear Adhesive) and not OCA (Optical Clear Adhesive). This is the adhesive layer in between your display and the glass. Apply the Loca on the display in sort of a Y shape on both ends, while leaving plenty of space on the borders
Above is how I apply the LOCA on my display, and I don't go too generous with it, otherwise you have to deal with a lot of leakage later. Remove all protective plastic from the new glass pane, and slowly lower it, bottom first, then top, such that the bottom becomes like a hinge for lowering the display on to. Do not be bothered if the liquid doesn't spread evenly at this point. Even a bit of air bubbles can be solved later. For now, press the glass down onto where you placed the 3M tape before, securing the glass on the body. This also helps the glue from coming out of the edges later. The glue will naturally spread a little after doing this.
I usually start by pressing the center of the display, to try and spread the glue out onto the whole display, and this process may take some time, especially if you're trying to get those pesky air bubbles out. What I do is that I slowly but surely get them into the edges, and make sure they don't appear again.
I then go over the display with a UV Flashlight of 365nm, on places like the corners where I'm happy with the results (i.e. no airbubbles), for about 15 seconds. The purpose of this step is to harden the glue a little there such that when you're doing your final bake, they don't suddenly creep up on you. Do this for edges where you have problematic air bubbles as well, and once you're done, it's time for the final bake.
I use a 48W UV light that I got off the internet, and I bake the top of the phone for about 20 minutes, then I remove the outer frame, leaving only the inner body + glass, and I bake the other side of the display as well for a further 5 minutes. This is to harden the excess glue as well, that way it's easier to remove and clean up.
When all that is done, it's time to put the phone back together, so I hope you remembered which component goes where and how, and where each screw goes as well.
The final results? A happy phone that's ready to be used again
Note: If you get a gummy/ Sticky home button with a bit of the glue seeping out, what I do is that keeping the phone upright at about a 45 degree angle, I drop about 3 drops of isopropyl alcohol down the home button, and let it go in a little, and using a cotton pad, keep mashing the button until the solvent thoroughly gets in and dissolves and excess underneath.
Sorry if this post was long, but I thought that my experiences would be helpful to others (y). Feel free to chime in on your own experiences/ thoughts on the process, as well as maybe some important information that I may have missed out that you feel should be added to the first post.
EDIT: A bit of an addendum to add to this topic as I feel I need to address a few questions or concerns
Q: Why would you want to repair the screen yourself? Why not just send it over to a shop to have it repaired for you?
A: The answer is quite simple. Cost. Over here where I am, Malaysia, the cost of getting a screen repaired via 3rd party repair shops is about 600 ringgit, or 200 USD. Consider that if you have the patience, skills, and materials to do so, you can do it at a fraction of the cost. For starters the glass itself can be acquired for under 10 USD if you're a smart shopper. Plus you're having fun!
Q: What do you need to perform this repair?
A: Here's a list of things that I use for repairs
- Packing Tape (prevents loose glass shards from going into your skin while you're working)
- Heat Gun (A hair dryer may do the job just fine as all you need is to heat up the glue to remove it)
- Plastic tools/ Spudges (chances are if you ever ordered replacement glass or what not, you should have some lying around)
- Forceps (thin metal tweezers. I use this to separate the capacitive buttons with greater precision, though if you have any suitable alternative, it could work just fine.
- Acetone (Isopropyl Alcohol. I use this to clean up the area after all the glass has been removed, to prepared for a new optical layer. I do not recommend the usage of thinner, as it's not very plastic friendly, neither should you use nailpolish.)
- 1mm or 2mm 3M 9448 Tape for Electricals (in the off chance that the glass that your order doesn't come with replacement adhesives to stick the glass to the body, this comes necessary. Standard double sided tape isn't adhesive enough so I wouldn't recommend it, though VHB tape could be an alternative; you just have to cut it into thin strips)
- LOCA (Liquid Optical Clear Adhesive. This is the glue layer in between the display and the glass. I do not recommend proceeding without it. It may look like a good idea at first, but once your phone gets exposed to the elements, or even pressure on the glass, chances are moisture is going to form in between the glass and the LCD, creating unsightly newton rings, and trust me, it's ugly; I've been there.
- UV Light for curing the LOCA glue (I use a 48W light. I tried using a UV flashlight to cure it before, but it didn't manage to cure the glue well, even after hours of exposure.)
Q: What are the costs of performing this repair?
A: The consumables in this repair don't cost much at all, though you will need to make a small investment in the tools. They still come up cheaper than sending it for repair however. Here's a list of my cost breakdown:
- Replacement Glass, 5-10 USD : If you know where to look, you can get it for under 10 USD each time, sometimes even below 5 USD.
- LOCA, 9-10 USD: Good for at least 6 repairs, even if you decide to leak it all over the place.
- 1mm & 2mm 3M 9448 Tape, 6.50 USD: Good for more than a few dozen repairs. mine came in rolls of 50M in length.
- Your time. If you're experienced, you can get it done in 3 hours or shorter, depending on severity.
=Tools= (these can be reused for future repairs)
- Plastic Tools, 5 USD (Again, if you have anything similar that you would like to use to pry open the display, go ahead. I recommend them being flat and wide however.)
- UV Curing Light, 35 USD
- Heat Gun, 20 USD (Free if you decide to use a hair dryer).
- Packing Tape, 2 USD (again, free if you have any of them laying around.
Q: Why do you need to use LOCA?
A: Unless you have an Autoclave machine lying around, you can use OCA. Chances are you don't and an Autoclave machine is around 3,000 USD. Let's not go there. LOCA sits in between your LCD and the glass. I won't pretend to know what exactly it's purpose is, but I'll tell you that your phone looks a LOT better with it, has less chances of breaking your Glass + LCD as there's less chance for it to flex and crack inwards, and prevents moisture from forming in between your LCD and Glass (which is bad!), forming unsightly newton rings. It also prevents dust from getting in where you can't reach it, and trust me, it's irritating as hell if that happens.
Q: Does LOCA come preapplied when the phone comes straight from the factory and does that means that my new glass is forever bonded to the LCD?
A: When your phone is made in the factory, it has OCA instead, which is a pre-cured version of LOCA. The only difference between OCA and LOCA is that one is pre-cured, i.e. OCA, and LOCA needs to be cured with UV lights. LOCA is not highly adhesive, so you can easily remove it after being applied, so no it doesn't take down the LCD with it.
Q: Do you need to use the UV Lights?
A: The answer to this is sort of a yes and no. The world around is is full of UV light, so if you're up to the task and it's a sunny day, then you could technically leave it out in the sun for a while, for it to work it's magic. I don't recommend it, but it's possible. If you however live in the clouds, or have 24/7 winters, I suggest you get the UV light. LOCA does NOT cure with heat, or being left alone. It specifically cures in UV light as I know it.
Q: This all looks hard and difficult! I don't know if I can do it
A: As with many things in life, patience and perseverance rewards you. I admit that this is not for everyone, but for those who do attempt it, I will assure you that you will learn something new, feel accomplished with yourself for fixing your own phone, and have possibly developed a new skill set that is capable of bringing you a source of income.
Q: If I send you my phone will you do it for me?
A: If you live in Malaysia, and do not mind meeting up with me/ sending your phone over (and of course, waiting), I'd be more than happy to help you fix your phone, though I do have to incur my own costs on top of raw materials. Feel free to message me for more details