[Johnny GTO]

I need to install windshield and rear glass on my 68 GTO . Is the Butyl Windshield Tape / Installation Ribbon Seal the same for both installations? There seems to be a conflict on the thickness on searches I have done. What is the correct thickness 3/8 or 5/16 ?

[Verdoro 68]

I used 5/16 on my rear glass. The trim fits nicely. I would imagine it's the same on the windshield, but I had mine professionally installed and he used urethane.

[gtohurstjudge]

I've always used 3/8.......It works great and that's what I've always read
is the recommended size.

[Ram4king]

3/8 is used on the windshield and 5/16 on the back glass is correct

[2002Z4CSS]

I would urethane the glass in instead of butyl tape. Make about a 3/8" bead.

[steve v]

I've always used 3/8" front and rear, no problems with the trim fitting.

[Johnny GTO]

Thank You everyone! Your input is much appreciated.

[69 RA GTO]

I have use 3/8 on both glass and no issue with trim on the past 3 cars I did.

[gtohurstjudge]

If you are looking for show quality glass installation, it is very very difficult
to use urethane out of a tube and not have it squish out in places where you can see it
beyond the side trim when looking through the glass. This is the most common flaw I
see on otherwise very nice cars at car shows. I've seen otherwise flawless cars with
visible globs of urethane all around the borders of the front and rear windows. You have
to realize that all the glass installers today are used to installing the glass on late model
cars with wide blackouts all the way around the border of the glass. They don't have to
be careful because the blackouts cover up the mess. There is another problem with urethane sealer out of a tube. Invariably the glass guy will get urethane on the side edges
of the glass when installing it. About four years later, the glass will delaminate on the
edges in the areas where the urethane touched the sides of the glass. The delamination
actually starts right away but it takes four years for it to creep out from under the trim
where you can see it. I can't tell you how many windshields I had put in my car before I figure out what was causing it.If you want show quality results, you need to use the butyl
tape, taking extreme care to lay it down right on the edge of the glass all the way around so that it doesn't show beyond the stainless trim, and you can't let it touch the middle
of the sides of the glass where the laminate in the middle is exposed or it will delaminate.