Urethane is an appropriate material for this application but will ultimately fail if exposed to UV light. What is missing from the clever technique you demonstrated is a primer or frit to protect the adhesive from UV exposure through the glass.

 

That is a great point. I have two thoughts on that. I have sent and email to 3M to see if there is any UV protection. Here is a link to the product I used. https://www.3m.com/3M/en_US/p/d/b40067015/
If it has no UV protection I think I will install the clear stone chip window film on the outside which has UV protection in it. That might be what I do. I am gratful u mentioned it because if i can give it UV protection I feel it will last,

 

Got this from 3M

Hi Mickey,

Thank you for contacting 3M, where we apply science to life.

3M™ Windo-Weld™ Super Fast Urethane, 08609, is not UV resistant.
Regards,

Allison C.
US and Canada Sales Operations
3M Automotive Aftermarket Division
www.3mcollision.com

 

From what I understand, what manufacturers use for this application today is (at least usually) a special type of methyl methacrylate. My company makes these and supplies customers for bonded glass.

we don’t have anything currently available for direct-to-consumer, but could possibly make something available to one of the Rennlist vendors if there’s enough interest.

Bonded glass isn’t a market I’ve worked with before, so I’m at the mercy of my counterparts there. And I haven’t done this project myself, and my company hasn’t tested the UV resistance or bonds on the 944 windows.

 

given the research i done, there is a decent size market out there for this. There may be other cars beside the 944 suffering this issue.

 

Had the same thought. I agree.

 

Wait--the factory bond is outside of the frame? Just trying to understand. I always figured the glass + frame bond is hidden (in the frame) and the black edging is just that--decorative edging (?)

In any case, this has looked like this since I picked up the car back in '08. I did have a hatch squeak but that was solved with these delrin pin seats I purchased many years ago https://www.only944.com/partscatalog...hatchpinseats/

 

My rear hatch was redone professionally twice in the last five years only to detach again.

I am hence debating whether Lexan, which is much lighter and perhaps with exerting less force on the frame, will stay attached (longer!). Also Lexan (unlike tempered glass) can be drilled and screws/bolts could be used to also physically hold the Lexan in place (although there is not much frame to screw into) in addition being glued.

Any recommendations/suggestion?

 

In my race car, replaced the denominated glass with 1/4" lexan. The frame does distort and difficult to restore to original shape without a big, obviously not available. My approach was to use the same 3M sealant for glass and used flat head screws and bolts. I did not apply sufficient sealant adhesive in some areas so I have a few water leaks but OK for race car. There are posts on how to do including mine.
WORD OF CAUTION: I cut myself with box cutter style knife, gash on left thumb, 7 stitches but no tendon, nerve damage.

 

Yep.. know that boxcutter feeling..



PS.. what happened to the ability to adjust the image size?

 

I did some reading on this type of adhesive and it sounds intriguing. It does everything a urethane adhesive does, but is stronger, still flexible, and more tolerant of imperfect surface prep. There are some adhesives of this type available in the consumer market. I'm inclined to buy some and rig up some tests using some pieces of glass and some kind of mechanism to apply and release a load on the joint. Test both types of adhesives and see which one wins.

 

If you really want to do this, please shoot me a PM with your address. I’ll try to round up some adhesive samples for you to test with.

 

Hi, I've been studying these dimples for a while now - yours is the best I've seen (closest to the trim)
Would you mind posting photos of how close the others are to the trim please.
This issue is the only thing that s#*#s me about my car.
Thanks

 

Bad weather, lighting, & camera combine to produce these less than stellar photos.. but, here you go

 

thanks, these pics are greatly appreciated - I dont think yours has pulled much if any at all.
I too, used to think that if the dimples were showing, that meant they had pulled out from under the trim. Now I'm not so sure.

I went and looked at mine again and the dimple on each side of the car (the one most far away from the centerline of the car) are exposed the same amount as yours in your first photo, but closer the dimples get to the center of the car the further they are away from the trim. Mine has definitely pulled at the top/center - but yours in nice and even.

Do your have weaker hatch struts? Protect that thing with your life!!

Cheers