1/4, 5/16. Or 3/8 butyl for windshield?, Or go urethane? Options

[iankarr]

Hi guys,

My glass is out and I was originally planning to have it professionally reinstalled, but these days the pros are only using urethane. I know that urethane is much stronger, but I've read that it may not be the best choice for our cars because it makes future removal difficult without damaging the channel.

Thoughts?

And if I decide to go Butyl, what thickness do you recommend?

Thanks!

[76-914]

I've done both and prefer butyl. I used 5/16"

[TheCabinetmaker]

Butyl stays somewhat pliable. Urethane not so much. Our cars are designed to flex. New cars are designed to be rigid. Urethane will crack the glass on a 914 windshield. Btdt.

[McMark]

(IMG:style_emoticons/default/agree.gif) 5/16" roughly equals 8mm, which is what the factory manuals call for.

[dangrouche]

I used 3/8". Do not use urethane. I considered it, but after reading up on it, would not use it.

here was my writeup:

http://www.914world.com/bbs2/index.php?showtopic=235156

3/8" was a bit tight getting on the trim. So if I ever do the job again, I would use 5/16"

[shoguneagle]

I have used urethane for several reasons: it is what the windshield replacement shops are legally required to use; wanted a positive solid seal using 914rubber's seal; do not have body flex to worry about; replaced by shop; must be something else but can't think of it.

Butyl rubber is easier to use since I did not have any problems replacing the windshield in another 914. Do not forget the clips and the rubber spacers that go at the bottom of the windshield.

My current car does not have any body flex since the seams are selectively welded, repairs to the hellholes and sheetmetal including longs, installed both the longs sheetmetal on outside and the inner cockpit kit. In addition, the seams at the bottom of the A-Pillars has been stressed and welded. The car does not have any flex thus providing a basis for a heavier suspension system.

The foregoing is the reasoning I did not use butyl rubber. My car is not original and never will be. Use the butyl rubber since it is the easiest and probably the cheapest way of doing things correctly. I do not know if the urethane use over time will crack the windshield so we will see what happens over future years. Just looking at the stressed points on my car, there should not be flex enough to cause any breakage.

Steve