At this much referenced windshield install resource:

http://www.speakeasy.org/~pws/Corvette.htm

It says to use a 1/4 inch bead of urethane sealer under and on top of the 3/8 inch butyl tape. So you basically sandwich the 3/8 inch tape between the urethane sealer.

Is this because you have to make up for the replacement windshields being thinner and to make it easier to push down to the correct height so the moldings fit flush? I can't think of any other reason to need anything besides just the tape.

Where do I get it? Is this a hardware store item?
Does it go by any other name?

These may be dumb questions but as you can imagine, I don't want to get this wrong.

 

what do you want to use the tape or the urethane sealer?

 

Just use the urethane and call it a day

 

I'm just about to do this same repair. I bought some modeling clay and placed it in several spots around the perimeter of the frame. I then installed the windshield temporarily and fitted the trim around it. I did this to check the installed height of the glass. I don't like having a gap between the trim and the glass for water to get into. I pulled the windshield back out and measured the squashed clay. It varied from 3/8" to 5/8" in some places. The only way I can fill gaps like that is to make a sandwhich like you decribed, (IMHO). I was surprised at how big the gaps were but I've heard others have the same gap on this forum. I don't know if I have the stock glass or not, it could have been replaced at some point by the PO. The butyl tape I heard someone say they could get it at NAPA or some other auto parts store. I got mine online along with 3m urethane in caulking tubes. Also got the pinchweld primer. I also plan on using the setting blocks, (just two at the top), to keep the windshield from falling in too far under it's own weight, or maybe it can sink during the summer heat, the urethane may get soft. Not sure about this last point, just being cautious.

 

I bought some largere rubber washers at the hardware store. They are 1/16 inch think. I plan to cut them into small rectangles and stack them one at a time until I get the height I need. Then I make sure to apply the tape and urethane sealant making sure it is well above the stack of washers. Then press in until seated on the rubber washers. and check with the trim to be sure.

I guess I have to try to find that urethane sealer. Do you remember where you got it? That way if I can't find it locally I can order it.

Thanks for the help.

 

The urethane can be bought at any automotive paint/body supply house in a caulk tube. BTW, wear gloves, the stuff is nasty and hard to get off of your hands!

 

I used both, like the sandwich method--- to make separating the glass from the adhesive at some point easier..

Its my understanding that the urethane to glass seal is tough to break w/o cracking the windshield; so I thought that the butyl to urethane seal might be easier to split if I ever needed to someday.

 

I’ve always used the old ribbon tape for my personal installations. The same stuff GM used when the windshield was installed at the factory.

However, there is an issue with this if you are doing this commercially and we use the urethane on customer’s cars. If you are using urethane a constant bead around a 1/4 – 3/8” will be just fine. The windshield will settle in when you install it.

Use two people if using urethane and test fit the windshield before you ever put the urethane down. Once you lay the windshield in the bare frame use a grease pencil and mark the areas where the center support tab holds the windshield upward as well as the two support brackets on the outer edges. This will allow you to keep a close eye on “center” and after you put the urethane on the windshield frame you really don't want to move it to correct a problem if you have it off on one side. The urethane will stay pliable but it’s not smart to set the windshield 1/4” to one side and then try to slide it to the proper position.

Just a note here too! When you do install the windshield you have to be careful of the upper outer most clips. These clips will scratch the edge of the windshield if you do not pay attention and usually result in a cracked glass. When setting a new or original glass just be careful of these two clips.

Originally the windshields were set with 3M 08611 Ribbon sealers is 5/16” thick and 3M 08612 is 3/16” thick.

Now you can’t use the thicknesses listed above as a measurement for laying urethane down. The windshield will settle in the urethane easier than it will in the original style ribbon tape.

I like the 08612 simple because it allows the windshield a closer fit to the windshield frame and requires less work to achieve proper seating in the frame. If you use the 5/16” thick ribbon, you will have to rub the windshield while pushing downward (scary) but the glass will seat downward eventually.

This is fresh in my mind so I thought I would post. We just put my original windshield back in my LT-1 today!

Willcox Inc.

 

That helps a lot, thanks!

 

Hi AW,
I used 3M #08610, which is 1/4" round ribbon sealer. Very close to Wilcox's method . I used glass from Classic City.
I didn't use any spacers but did use a foam damming strip (from Toyota !!!) which helped support the glass just a tiny bit. I felt that the ribbon sealer was acting solid enough that I didn't need to use spacers. The original windshields were installed using a foam damming strip to keep the Thiokol sealer from oozing out onto the glass where it would be seen. No one talks about this damming strip anymore even though you can clearly see it on original windshields.
As soon as I had the glass in place, I put the 2 pieces of SS side trim on to make sure the glass hadn't compressed the sealer too much and to make sure the gap between the glass and trim was right.
Regards,
Alan

 

Well I just got back from the stores and here is what I have.
3/8 inch ribbon sealer - 15 feet.
3M- 08609 Windo-Weld

My only concern now is I have different views on the ribbon sealer cross section size ranging from 1/4 to 3/8. What I will do is dry place the glass and see what gaps I have. If I need less than 3/8 then I will pre-compress the ribbon a little. Either way I will ad a bead of the urethane on top of the ribbon and I should be good. I will let you know how it comes out. Might be this weekend or next.

 

I had to remove my windshield and luckily it was held by butyl and came out in one piece. Urethane is usually a one shot deal because the windshield usually breaks when removing. We maintain a fleet of 500 vehicles and go through a few windshields a year which we have a windshield/glass vendor for and he said to use butyl when I re-install the windshield.

 

It is a good idea to use the primer on the body and glass. I noticed in your material list it wasn't on it. 3M8684 or 8682. Also a note on the 8609 urathane is it takes 24hrs to cure and shouldn't be driven for 48hrs. This info isn't on the tube but 3M tech will confirm this. Just alittle helpful info.

 

Some urethane sealers are primer less