kwikt

Sounds interesting as I bought the 3M sealer and just 1 of the 3M primers a few months ago but have not attempted this project yet. I'm going to wait for more testimonials before I pull the trigger.

william_b_noble

well, Kwilt - if you are going to do it, spend the $15 for which ever primer you didn't get, and use them exactly as directed, in the proper sequence. I cleaned the glass with acetone first, I imagine that it helped, but I have no way to know.

V2Rocket

william,
would you be willing to do another hatch if i dropped it off?

StickShift

I have been through this, I had success in the past with the two stage primer from 3M, but it is no longer available, they only have the single stage primer, which doesn't work. Well, it works for about a week... After four failed attempts with the 3M product I gave up.

I bought my Sitka products from a local windshield installer.

V2Rocket

Is there anything that could be done to a hatch that isn't separated yet but sounds like it might be starting to come undone?

I just put a new hatch onto my car that the glass is still fully in the frame but over the last few days it has made "that popping sound" like it is starting to come undone.

Could I run a thin bead of window-weld in the crack between frame/glass to hold it together...or what?

Ky944TurboNewbie

Disconnecting the gas struts could keep the hatch in the current state.

V2Rocket

The struts are 7+ years old so I don't think they're pushing very hard anymore.
That said the noise I hear is only while driving over uneven pavement (like steep driveways/gutters at an angle) so the car is flexing...

Dandy_don

Whatever you do, do not use the 3M urethane and their one part primer. The primer, when exposed to the sun's UV rays delaminates from the glass causing adhesion failure. I did mine with 3M and it lasted about a year. Have just redone it using Dow BetaSeal urethane and single part primer. Had difficulty getting the Sika urethane and 2 part primer otherwise would have used that. Separate the glass from the frame using a torch, get everything clean and then glue the glass to the frame with the frame mounted on the car. I also had a local welder weld an aluminum tab 4" long x1.5" wide to the frame centered on each hinge location. If I had it to do again I would have him weld a continuous tab from hinge to hinge extending 2-3" beyond each hinge. That would probably double or triple the effective bonding contact area right where it counts. To cover the tabs I just broaden the area where I paint the primer on the back side of the glass. It looks stock.

gregeast

The tab sounds like an excellent solution, any chance you could post a pic?

Thanks for all the information guys, I have my extra hatch about half out of the frame, hoping to finish once the weather cooperates.

V2Rocket

Bump, ideas for preventative maintenance for a frame just starting to separate?

Dandy_don

Can't imagine that there is any thing you can do to stop the rest of it delaminating or leaking. As others have said do NOT use silicone to try and seal it up. Silicone residue is very difficult if not impossible to remove. When your hatch does finally separate enough to cause you to fix it then having silicon residue on either the glass or the frame or both will likely prevent a long term bond and all of your work will be wasted. If it leaks use black gorillla tape on the outside to seal it.

V2Rocket

Anybody ever thought to use rearview mirror adhesive for this repair?
That s**t will never come off and is 100% in sunlight.

william_b_noble

Dandy Don's comment about 3M urethane is misleading - the tubes I used recommended two specific primers in a specific order. With those two primers, the hatch I repaired has been perfect for over 5 years. If you use the wrong primers, all bets are off

V2Rocket

many people are of the opinion that separation is exacerbated by the hatch shocks basically pushing the glass backwards (not sure i buy that 100% since they are attached to the frame, not directly the glass)...but what if one were to try flipping the shocks around, so that rather than having the shocks pushing towards the rear of the car, they push forward (encouraging the top of the hatch to stay engaged to the frame)?

How is a third-gen Camaro's hatch glass held in place? Can we learn anything there?

Dandy_don

I do not believe that 3M any longer has a two part primer available. When my hatch delaminated after using the one part primer that is available, I called 3M and they confirmed that there is only a one part primer available ( I did not know there ever was a 2 part when I talked to them) They told me that I did not clean the glass well enough and that is the reason it failed. After thinking about how it failed- began in one area at top right corner of hatch and then uniformly (over 2-3 days) separated all across the top of the hatch, and reading accounts of other 3M failures I decided that I was never going to use 3M again. The Dow Beta Seal has been on the hatch for about 4 months now, no sign of delamination but that is not a long term test in my view. If it lasts longer than a year then I would recommend the use of the Dow product. If you can find a two part 3M primer then you might want to try it. If all you can find is the one part then don't bother. If mine fails again I will use the Sika flex products.