I have read a lot on this site about the preference for for butyl tape over urethane. My installer says he can and will do anything I want but says that the urethane applied with a caulking gun is superior to butyl tape for safety and leak prevention. He said there will be no problem fitting the chrome trim because it lies flatter than the butyl tape.

What is the problem with using urethane?

Thank you,
Jack

I've only ever used Butyl tape....but that's just because I know it.

The problem I have heard (but not experienced) is that the urethane doesn't allow enough flex for the windshield. The car flexes (as 914's do) but the windshield does not and you get cracks or breaks in the glass.

FWIW I've been running urethane for about a year without any problems.

I have heard that urethane also does not allow flex. This could be a problem in the future for me since I have used the urethane along with rubber trim around the windshield. The body flex in my car has been minimized if not eliminated by use Brad Myuer Long reinforcement kit along with some selected seam welding and limited bracing.

The seams at the bottom of each "A-pillar" has been welded to help eliminate the any potential movement to the windshield.

Sorry I do not have the answer. My car was stolen and has not many miles on the project build. Since theft I have spent the last 18 months repairing and wiring from the theft.

Biggest issue is the stock trim. If you get that urethane on the trim and break another windshield it's as good as junk. Old cars have butyl and gain nothing in strength by using urethane.

Butyl

Rick nailed it. New cars are "designed" with the rigidity of a glass frame glued with urethane. Not our flexi-flyers

To me it's not the outside of the car, it's the inside. If that bead of urethane is just a little too thick, then you won't be able to get the seal between the dash and the windshield on the car. kinda hard to explain why, but if you look at that seal inside the car (or better yet take it off) you'll see exactly what I mean.

butyl =flex

Traditionally, that seal is done when the windshield is out of the car...

That said, I use butyl. It's what the car was designed for, and allegedly it will give more than the urethane.

--DD

Butyl. The PO of my car did urethane and it looks like sh##. The chrome will never come off you can see where the urethane squeezed and went into the lower rubber and the side pillar trim.

Butyl - for all the reasons mentioned above.

Before talking options with my installer, he launched right into recommending butyl - it's what I wanted so I didn't ask why...

Butyl has served my car well for 40 years...

Thank s everyone! Butyl it will be.

A word of caution. Make sure when your glass installer sets the windshield with butyl he doesn't back fill it with urethane. In MN it's the law I guess. Even rubber set glass. That's what I was told anyway. I booted the installer and did it myself.

My installers used urethane because of the MN liability law, i used butyl when i installed it myself. i know there is talk of the windshields breaking with the urethane install but has this happened to anyone or just speculation.

My car has had urethane for years without issue.

I use a rubber surround and frit paint rather then the stock trim, but I doubt that make a difference.

Zach

Do it yourself.

One of the easiest do-it-yourself jobs on a 914.

Do a search with conedodger, windshield, tweeters, install as parameters and you will find my install. I did it by myself but you may want a partner as it sticks pretty permanently on contact...