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Posted by: porsche914_73 Jul 18 2018, 07:32 PM

Hi Guys!

Questions and more questions about windshield/rear glass sealants to use on my rebuild:

1. What is the correct size of butyl tape that I should use when reinstalling the windshield and rear glass?

2. Any reasons why I should use modern windshield sealant instead of butyl tape like the factory did?

3. I'm going for a dechromed look on my rebuild (L96B Alaska Blue with dechrome and roll bar vinyl delete, gloss black painted bumbers, rockers, 2.0 Fuchs). Have anybody had any experience with the windshield rubber moulding kit that 914rubber.com sells?

http://shop.914rubber.com/914-Windshield-Chrome-Replacement-Rubber-914WSR.htm;jsessionid=E5CF99723CCEF242D89EEE373B310388.p3plqscsfapp002

I believe the butyl tape it should be 10mm as used in a kit on 914rubber.com for the rear glass but want to make sure that is the size. Last time I got a windshield installed, the installer used the black goo adhesive that comes in a tube but excess can be seen on the edge past the chrome moulding so also affecting the height glass and the moulding fitment. Have no doubt that it will hold but maybe he just used too much. What adhesive do you guys use/prefer? There's some butyl tape/rope/cord for sale on eBay (1/4, 3/16 and 5/16 sizes) and it states is suitable for windshields but open to your opinion.

http://www.ebay.com/itm/Windshield-Sealant-Tape-Butyl-Adhesive-Seal-Kit-253786-5-16-X-15-ft/232841848352?hash=item363674a620%3Ag%3A3k4AAOSwu7hbMJN3&_sacat=0&_nkw=butyl+tape&_from=R40&rt=nc&_trksid=p2334524.m570.l1313.TR7.TRC0.A0.H0.Xbutyl+tape.TRS1.TSS0&LH_TitleDesc=0%7C0


Thanks for your comments,

Posted by: 76-914 Jul 18 2018, 07:39 PM

5/16 (8mm)

Posted by: ConeDodger Jul 18 2018, 08:42 PM

I think we’re onto a theme...

Butyl tape is the only way to go. Modern sealant drys hard and the windshield will then flex with the windshield hoop. With the roof off, it flexes more. This is why new windshields are cracking within a year of installs.

Get a kit and do it right...

Posted by: The Cabinetmaker Jul 18 2018, 09:02 PM

. Butyl tape only. No urethane!

Posted by: porsche914_73 Jul 18 2018, 09:14 PM

Thanks guys for the input. Another question, butyl on the frame or on the glass? Done plenty of work on cars but have to admit is my first windshield install.

Thanks!

Posted by: six Jul 18 2018, 11:00 PM

Buytl on the frame. Make sure the frame is clean with alcohol or they even make a special primer that you paint on with a small brush to make the buytl stick better..
Also make sure to install new clips for the windshield trim in the window frame first.
Place a couple of tiny rubber blocks the thickness of the windshield and about 1/2 inch long at the bottom of the windshield frame so that when you set the windshield in place it doesn’t creep to the bottom of the frame but stays centered so the gap is the same all the way around the windshield. Do a trial fit before you lay the buytl in place to make sure everything is centered. Otherwise the trim will not snap in and lay flat. Leave the rubber blocks in place and install the trim over them.

Posted by: Racer Chris Jul 19 2018, 07:30 AM

I use 3/8" for the windshield, 5/16" for the rear window.
It supports the glass better with a wider contact patch.

Posted by: 76-914 Jul 19 2018, 12:21 PM

I’ve used 3/8” once. I needed to really work the windshield in the hot sun in order to get it low enough for the aluminum trim to click onto the plastic clips. As mentioned above; test fit it first and see if the gap is uniform. If not then I’d use 3/8” again. Otherwise 8mm works fine for me. Just be sure you can see that the butyl makes contact all the way around. It will be obvious.

Posted by: Ansbacher Jul 19 2018, 12:36 PM

The butyl tape sold by NAPA is wonderful stuff. Very easy to work with.

Ansbacher

Posted by: six Jul 19 2018, 04:46 PM

Had to check my records before I took a WAG but...1/4 inch Butyl is the correct size. Any larger and the window will not be flush with the frame. Trust me.
Also 1/4 inch is the correct size for the rear glass too.

Posted by: Mikey914 Jul 20 2018, 01:37 PM

If you are using the rubber to replace the chrome you will need to use urethane to install. Ypu will mot need the windshield spacer block or clips. You will want someone with a steady hand to make the bead as without the extra 1/2" of metal to hide the bead you can see it so it must be pretty.

Posted by: porsche914_73 Jul 21 2018, 07:38 AM

Awesome tips! Thanks!