iMac adhesive screens tips and tricks, best practices

[timeshifter]

What are your tips and tricks and or best practices for working with iMacs that use adhesive strips to hold the screen on?

It's not something I do frequently, but when I do, I hate it. Last night I did a 2013 21.5" iMac. 90% of the work was in removing the old adhesive. Probably spent 1.25 hours picking away, scraping, etc. I've been using denatured alcohol as a solvent to clean with. It's done OK in the past, but now I realize that isopropyl alcohol that 90% or better is the preferred cleaner. Don't know if I had started with that if it would have been easier. I'll find out soon as I have a 27" to work on too.

I only buy replacement strips from iFixit. When I'm putting it back together I use blue painters tape to hold the screen on for testing.

I'm not looking forward to doing the next one, even thought about farming it out to another local shop. I have a lot of Mac customers, and turning away the upgrade business on those machines is not an option.

But, if I could find a way to make the adhesive screen bs more tolerable that would be good.

 

[Markverhyden]

First, are you using a heat gun on the screen edge before the removal process as well as during cleanup? I've found that to work very well in making it easier and removing more of the adhesive.

I also use painters tape for temp securing the screen when ever needed.

It's been a long time since I've had to upgrade one of those. I have one I inherited from a customer which it turns out it had a bad HD. So I just tossed in a spare SSD and secured the screen with painters tape. I did buy some very narrow 3M autobody tape to try as a substitute but haven't tried it yet. Given the cost of the kit from iFixit I doubt I'd use that VHB tape on a customer unless it was some kind of an emergency.

Some removal tips I learned from some R&D folks when I worked at a company that made all kinds of tape, if you haven't tried them already.

1. High temperatures or very low temperatures can weaken the tape adhesion to the substrate. You can use canned air to get very low temps but I'd be nervous near any components like the camera or mic.

2. Another strategy is as soon as you've removed tape pieces immediately go back and dab the remaining adhesive with what you pulled off.

3. The best way to peel tape is to double back on itself so you are pulling horizontal to the remaining tape. That is when the adhesive forces are the weakest. Another option is to use a finger pushing down and along the path of the adhesive. Kind of like rolling a snowball so to speak.

 

[overburnz]

What are your tips and tricks and or best practices for working with iMacs that use adhesive strips to hold the screen on?

It's not something I do frequently, but when I do, I hate it. Last night I did a 2013 21.5" iMac. 90% of the work was in removing the old adhesive. Probably spent 1.25 hours picking away, scraping, etc. I've been using denatured alcohol as a solvent to clean with. It's done OK in the past, but now I realize that isopropyl alcohol that 90% or better is the preferred cleaner. Don't know if I had started with that if it would have been easier. I'll find out soon as I have a 27" to work on too.

I only buy replacement strips from iFixit. When I'm putting it back together I use blue painters tape to hold the screen on for testing.

I'm not looking forward to doing the next one, even thought about farming it out to another local shop. I have a lot of Mac customers, and turning away the upgrade business on those machines is not an option.

But, if I could find a way to make the adhesive screen bs more tolerable that would be good.

The iMac original VHB strips are fairly easy to remove, I just use a black stick to peal the tip and pull them away, (after separating the display from the housing of course) if the VHB are not from apple (ifixit, owc etc..) those are a PITA and you WILL loose a lot of time removing those...

 

[overburnz]

for a oppening tool use this

 

[timeshifter]

First, are you using a heat gun on the screen edge before the removal process as well as during cleanup?

For opening / removing the screen I use the pizza cutter that @overburnz pictured above. I did break out the heat gun after the screen was removed to try to help with cleanup, but it wasn't too helpful. Mostly I used my thumb and rolled and bunched up the adhesive.

I may try the heat gun for opening the next one. If I use it to help with the cutting and initial seal breaking, is it still effective when those parts cool off again, before i remove the screen?

I'm apprehensive about applying heat though. Any tips?

 

[overburnz]

I'm apprehensive about applying heat though. Any tips?

Don’t, like i said the pizza cutter is more than enough for the original VHB strips

 

[britechguy]

If one wishes to apply heat, but is apprehensive about a heat gun (which is almost definitely overkill), there is a middle ground: a blow dryer.

There are times where one can get "enough, but not too much" heat from a blow dryer that can ease a lot of fixative removal along with zero risk of melting or damaging anything.

 

[Captain Spaulding]

You don't need to use a heat gun at all, don't use one.

There are two types of adhesive and two types of pizza cutter, you need to be careful which ones you buy. Buy the official Apple kit, the adhesive strips have a foam core and are easy to remove again if you need to, once the screen is off the remaining adhesive peels off with ease the cutter blade is very thin. The Apple part numbers are 076-00331 for the 21.5" kit and 076-00332 for the 27" kit.

If you buy the unofficial adhesive strips they don't have a foam core and are a nightmare to cut without cracking the screen and once you have got the screen off it takes forever to remove the remaining adhesive. The unofficial cutters have a thicker blade and if you're not careful and push it right in straight away the screen will crack, a costly mistake! It's just not worth using non-official strips and cutters.

Some more tips:
Be careful when removing the video cable and screen power cable, you can damage the cable or connector port if you're not.
Once you have peeled the old adhesive off wipe the screen and unit with isopropanol before sticking the new adhesive so it gets a good bond.
before resealing the unit, attach the screen and hold it on with blue masking tape, switch it on and make sure it works OK.
It takes me about 20 mins to open one up, replace the drive with an SSD and reseal it.
It sounds like the original poster might have had one that had already been opened and sealed back up with unofficial adhesive as the Apple stuff you can peel away a whole strip in one go easily without using any heat or isopropanol.

 

[timeshifter]

Ok, now I just opened up the 27" iMac, similar vintage.

IT WAS A BREEZE. Took less than 15 minutes from start to finish in terms of opening it and removing the adhesive strips. They all just peeled right away, once I got enough pulled away to grab onto it.

At this point I'm gonna say that 21.5" I did the other day was a fluke. Presumably it had been serviced before or something.

 

[Captain Spaulding]

Ok, now I just opened up the 27" iMac, similar vintage.

IT WAS A BREEZE. Took less than 15 minutes from start to finish in terms of opening it and removing the adhesive strips. They all just peeled right away, once I got enough pulled away to grab onto it.

At this point I'm gonna say that 21.5" I did the other day was a fluke. Presumably it had been serviced before or something.

Yeah if it took you that long on the 21.5" to pick off the adhesive then it was almost certainly serviced already and sealed back up with non-official stuff without the foam core. Hopefully you used foam core adhesive to seal it back up!

 

[timeshifter]

I've always ordered my tape from iFixit. Don't know if it's foam core or not. Don't think I've ever re-opened one I did with their tape.

 

[Captain Spaulding]

I've always ordered my tape from iFixit. Don't know if it's foam core or not. Don't think I've ever re-opened one I did with their tape.

The description mentions foam so looks like you're all good