Drilling through Stock Glass Hatch

[Esprit1]

Hi All,

It is possible to drill holes through stock hatch?

Yes I already purchased a Lexan hatch and all mounting hardware, but just curious if I can drill holes and mount another functional hatch scoop on the stock glass. Another reason is that I heard with extended use and high speed, some Lexan hatches developed stress cracks around the mounting holes. Could the stock glass be more resistance to crack if done properly?

Best Regards
Paul

 

[NSX-Racer]

The glass used in our cars has some kind of internal structure to prevent splitting into 1000 parts. If you drill a hole in it you can get the same issues as when you have a stone punch hole in your windshield: You will see some cracks expanding from the hole after some time which could lead to a big crack over the whole glass.

What may work is: Cover the whole glass with a clear bra before drilling (like 3M). It may prevent cracks. That's at least what I would expect, maybe some glass experts know more here.

 

[ChopsJazz]

If you choose to drill through it, make sure you use a glass drill. Not any old bit will do the job.

As for the adhesive plastic between the two plys of glass. Good luck with that.

 

[ATERPAK]

I don't think you want to drill through the rear glass hatch. The hatch is made of tempered glass and if anything sharp starts punching through it, it will shatter into thousands of tiny little pieces. All glass on all cars except the front windshield is temepered. This has been done for safety reasons. You can cut and drill the front windshield since it's 2 laminated sheets of glass with an internal clear adhesive sheet between them. However this should be left to the experts since the windshields crack very easily if stressed in any way during the process.

To reduce the tendancy for lexan to crack where holes have been drilled, you should chamfer each hole to reduce if not get rid of any sharp edges made by the drill. This reduces any stress risers created in the material. If you can also provide a thin rubber washer between the fastener washers and the lexan as well, that will reduce the vibration induced into the hole which is part of the reason for the cracks forming. You should be trying to spread the clamping force load of the fasteners around the hole as much as possible. Finally don't overtighten the fasteners holding down the lexan. Use just enough force to keep it in place and no more. Make sure that the lexan is supported adequately on it's hinges and brackets and that should extend the life of the lexan.

 

[TTony]

Just laser drill it. No stress cracks, etc.

 

[drew]

TTony--that is amazing!

Have you done cutting of tempered glass before?

Drew

 

[Esprit1]

Thanks soo much for the excellent advise. Short of Lazer or High Pressure Water drill, I think I should leave this piece alone. I don't think its worth the trouble drilling the stock glass. Perhaps I'll just purchase another Lexan Hatch if I should change hatch scoop.

Per your advise, I'll try to spread the load across the Lexan using steel and rubber gaskets. So over tighten is a no no.

Best Regards
Paul

PS: Project makeover 1 month and counting.

I don't think you want to drill through the rear glass hatch. The hatch is made of tempered glass and if anything sharp starts punching through it, it will shatter into thousands of tiny little pieces. All glass on all cars except the front windshield is temepered. This has been done for safety reasons. You can cut and drill the front windshield since it's 2 laminated sheets of glass with an internal clear adhesive sheet between them. However this should be left to the experts since the windshields crack very easily if stressed in any way during the process.

To reduce the tendancy for lexan to crack where holes have been drilled, you should chamfer each hole to reduce if not get rid of any sharp edges made by the drill. This reduces any stress risers created in the material. If you can also provide a thin rubber washer between the fastener washers and the lexan as well, that will reduce the vibration induced into the hole which is part of the reason for the cracks forming. You should be trying to spread the clamping force load of the fasteners around the hole as much as possible. Finally don't overtighten the fasteners holding down the lexan. Use just enough force to keep it in place and no more. Make sure that the lexan is supported adequately on it's hinges and brackets and that should extend the life of the lexan.