Front and Rear Windshield Installation. My 1st time, advice please
 

My next project is to install the front and rear windshields. I bought via Ames as I usually do. Of the two options Ames offers; I opted to buy the “weld and primer” rather than the ribbon seal tape. I have never installed windshields; so I would like my first attempt to be successful. I could use suggestions and advice before I proceed?

I have fooled around a little with this, and IMO think it is worth having a pro install the glass using urethane. You can usually find someone that will make a house call and do it in your shop. Since they do this all day long, they just have a knack for getting the urethane thickness correct, etc. Mess it up and it is a huge sticky mess to deal with!

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X2..glass replacement is cheap.

True; I do have local windshield installation guys that make house calls. This may be a sensible option. As I recall from an inquire 2 years ago, about $100 per glass to install.

Will be the best 200 you ever spent! :)

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Agree with the others. Pay a professional and use urethane adhesive. It's not that expensive to have it done right using superior adhesive.

When having someone else install it .... are the trim clips etc all installed prior to the glass going in, or after?

That needs to be done by professionals using commercial grade urethane.. For the couple hundred bucks it would cost why bother..

I did my 70 Lemans windshield on Sunday. I used 3M ribbon 3/8". The glass was 70's replacement, not the original. I had a buddy help. We set the glass and used the adjustable stops on the bottom to set height first, had to make the hole on the driver's stop a little longer to get the driver's side right. We took the blocks from the ribbon set and I had some others and they measured at 5/16" approx thick, set two on top and one on each side with masking tape to check height for molding. Looked nice and tight. We then used 6 pieces of masking tape, two on top, two on bottom, and one on each side and cut with fresh blade. I quadruple checked the spacing all around until I was sure.

I polished the glass with a buffer and Sonax glass polish, made huge difference on an old glass and wore me out. I cleaned all surfaces on glass and body with Isopropyl Alcohol. The weld was painted so I chose not to use primer, primarily because you cannot find butyl primer in Europe. I installed the clips and touched up with some paint for good measure, I will be dead by the time they rust out, if they do. We then laid the ribbon nice and slow working together, one rolled out while the other cut the paper strip away etc... stayed on edge of pinch weld and butted the ends being careful not to stretch. Looked good. I gotta admit I was scared but what the hell. We used suction cup holders and got it up there and put it in, done. Worked it a little bit by going around the glass with mild pressure, you could see the ribbon sealing up. I used a mild setting on heat gun as well. Molding went on nice and tight and looks good. I made a mistake and laid the ribbon a little high on the bottom and you can see half of it beyond the stainless molding but so be it, this is not a $100K car. I saw one shop on youtube uses detailing spray on the ribbon and then sets the glass, the spray lets the glass move around until they pressed to seal. Looked like they do a lot of old cars that way.

Now, I know the discussions about ribbon vs urethane but this what I chose to do. It was not hard but you have to take your time. If it works, great, if not I will deal with it.

Yes, install trim clips first. Otherwise you may be fighting with clearance between clip and urethane

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Yes, I do have all the trim. Smart thinking, thank you.

I've done quite a few windshields, always alone. Never had a single problem except for the one time that I decided to use urethane instead of butyl tape.
My advice, if you're going to use urethane, pay someone to do it. If you don't have a way to heat it, forget about it. It's a nightmare to try to get it to flow out. I literally destroyed two caulk guns trying to get it to flow and it still leaked.
I took it to a glass guy to re-do and saw what the trick was...they have a heated holder that you set the tube of adhesive in. Once it's heated, you put it in the gun and it flows right out.
By the way, another trick he showed me.. To check it for leaks after install, spray a foaming type cleanser around the outside perimeter of the glass. Use an air nozzle on the inside perimeter of the glass. If there is a leak, the air will blow the foam away. Also, you get once chance to set it in the right position. To test fit the location, set the glass in the opening 'dry'... use a couple of strips of masking tape across the glass and extending out onto the surrounding metal. Use a razor and cut the tape where the edge of the glass meets the surrounding metal. This will make alignment quick and easy when you have the sealer down. Just match the tape lines up.

WOW, didn't know it had to be heated. All the more reason to pay a pro.
I'll try that leak test after completion.

I broke the windshield during a failed engine installation. The glass company guy came over and took out the windshield and I asked if he could delay installing the new one because I wanted to fix the rust hole in the dash . He agreed and installed it a few weeks later. $199.

I've installed a bunch of front and rear windows using butyl. It's super easy, and the butyl sets the depth so there's no guessing.

It's easier with two people, but it's not impossible to do by yourself. Hell I installed a Grand National windshield by myself, and that was a pretty big piece of glass.

Dont pay someone else to do something that you can do, that's my motto.

on my 2nd gen cars i pay a pro to do the front windshield, was $50 to install & is now $75 & includes the urethane. he uses 3M window weld urethane in a caulk gun, has never heated it & it flows out pretty easy, but he has a industrial type caulk gun, not your average residential type. the trick he showed me is to cut the tip in a wide V shape, that makes it come out easy but more important it comes out in a 1" tall thin wall, not a normal bead you get when you cut the tip straight or at an angle. when you lay the glass in it smashes the wall of urethane into a thick bead that fills any gaps or uneven spots for a complete seal that a normal bead might not, & it lets the glass sit at the right height. 10+ years on 1 car, 8+ on another & 6+ on the most recent one & no issues or leaks at all, hard driving & drag use too.

for the rear of the 72 i did it myself with the butyl tape & a helper to lay it in place. i think it was 3/8" thick maybe 1/2". a trick my paint guy does with the tape is after the glass is in, run a small bead of the urethane around the edge of the glass to ensure a water tight seal.

im all for doing things yourself but for something critical like installing a windshield i dont like to experiment on my own higher level restorations... if you mess up it's very difficult process to remove urethane from the channel & glass, thats stuff is nasty when uncured or cured. spend a couple hundred to do it right.

Was that a manual caulk gun or electric? I literally bent the squeeze trigger on mine. Ran out and got another one and it did the same thing. That stuff was like trying to squeeze mortar through a half inch hole. The glass guy had a heated holder that he left the tubes in until the urethane was hot enough. Flowed right out then.

actually the first 2 times he did mine it was manual & probably 2-3 times as beefy as one you'd run out & get from home depot, & he would have used that probably hundreds of times doing this. the most recent one he did for me was electric. but the trick that made the manual one work fine was how he cuts the tip... its not just a half inch hole, it was a large "V" shape notch probably closer to 1" long that allowed the urethane to flow out much more freely & in the shape of a tall thin wall.

when i did the back glass i just used a normal cheap caulk gun with about a 3/8" hole & it came out pretty easy, harder than normal silicone window caulk but far from mortar & the gun was fine afterwards. im sure pros in a shop use a heated gun when they do it all day long, but this guy that does mobile service did fine with a manual one.

Maybe I had a bad batch. I don't care how you cut it, what I was using wouldn't have come out.

We use electric guns. Some urethanes are suppose to be heated & others done non heated. I would not blow any air at the urethane unless it is dry, its thick but don't risk blowing it out. You do have some adjustment but if you are way off good luck. You would need the right size spacers to set & keep the height right until it drys. Newbies put way too much down & you will have a lot showing on the inside which looks like crap. Spend the money on a pro

I got a replacement windshield installed, at my house in my 72 Lemans convertible for $300. After watching them, I wouldn't have wanted to do that one myself. I have replaced my 55 Chevy and 80 Fiat spider conv. , and they're all different. If you do it yourself, be mindful of how much seal you put on and how much you press your new glass to the seal for your moldings to fit.

I am leaning towards using the ribbon when I install my glass. One thing I wonder was if it would work out better to lay the glass on a padded work stand with the interior side up, then apply the ribbon around the edge of the glass. This way you know the ribbon can't be in the wrong spot (too high/too low) when you put the glass into position.


Does this sound like it would work?


Thanks

These cars had butyl tape from the factory......and that’s what I used in my front and back glass 67 gto. The butyl tape gives you the correct height ,for the the glass....so the moldings fit correct.

I’ve always put the tape on the channel.....and all the Windsheild guys I’ve had in my shop ovah the last 40+ years ...do it that way.. plus it’s nice to have those pump up suction cups....Incase you have to slide the glass ,one way or the othah..

A 67 GTO never used butyl tape. Look in the Fisher body service manual, only used urethane

Well they must have run out of urethane that day...cus my ORIGINAL WS ...had butyl .

The Butyl can keep your spacing correct, and used as a dam to hold the Urethane.

Here you go

http://www.beldenspeed.com/technical...lation-details

and here you go

Below from John Hinckley. If you don't know who he is, here's a little info. http://www.corvettemuseum.org/librar...hinckley.shtml

John Hinckley: "GM never used butyl tape or anything like it to install windshields or backlites. Period.

The body opening flange was coated with black silane primer using a flow-brush 30 minutes prior to installing the glass, and all the reveal molding clips were installed to the Body Shop-installed weld studs.

The glass was placed on a powered rotating fixture, inside edge up, retained by suction cups.

The glass periphery was cleaned using a solvent, dried, and a different silane primer was applied.

A fabric-reinforced self-adhesive foam rubber "dam" was extruded and applied to the glass just inboard of where the Thiokol adhesive would later be applied; the purpose of the "dam" was to contain any Thiokol "squeeze-out" so it wouldn't show from the inside past the edges of the interior garnish moldings after the glass was installed to the body.

After dam application, pumpable Thiokol adhesive (with a pyramid-shaped cross-section created by the dispensing tip) was applied adjacent to the dam, all the way around the glass.

Lower glass supports were fixture-located and screwed to the cowl, and rubber spacer blocks were glued to the opening flange. The spacer blocks set the height of the glass relative to the body to ensure a good fit of the reveal moldings.

The prepared windshield was removed from the rotating fixture, installed in the body opening, and pressed down against the rubber spacer blocks; wooden tonque depressors were used to "paddle" the Thiokol around the edges at a 45* angle from the top edge of the glass to the bottom edge of the body opening to ensure a continuous seal all the way around the glass.

Reveal moldings were installed.

That was the plant production process, and explains what is sometimes described as a "rope" being found when an original windshield is removed - the "rope" is the fabric-reinforced rubber "dam" that was applied prior to applying the Thiokol adhesive.

If you'll look in Section 4 ("Fixed Glass") in the Fisher Body Service Manual, you'll see exactly the same process for windshield replacement, except the "dam" wasn't included with the Service kit - masking tape was used instead to control "squeeze-out".

The Thiokol installation passed the Federal MVSS windshield retention tests, and contributed substantially to the body's torsional stiffness; it also helped the structure pass the roof crush test. It's illegal to replace a windshield with butyl tape, although some glass shops do it as a less-expensive short-cut method instead of doing the job right."

I had a mobile glass come and install front and rear glass on my 78 Trans Am. The install cost was $70 for front and $70 for rear. I reused the old rear glass and he sold me new front glass for $150 - this was about 5 years ago. The installer used
SikaTack Drive Adhesive and a Dewalt 18-Volt Adhesive and Caulk Gun. I posted some pics in this thread
http://forums.maxperformanceinc.com/...ght=windshield

Thanks for that info Brad900

I made the mistake of using urethane for the windshield on my 71. The glass sits too low in the opening, making the trim fit weird.

Ever since, I've been using the correct thickness butyl and everything lines up perfectly.

I've heard and read that using urethane can make this project a challenge regarding thickness. I'll certainly need shims at this bottom of the windshield.

the install height of the glass depends on how much & the way you put the urethane on, sounds like you didnt use the proper amount. the pro that did mine specifically stated the urethane needs to be at a certain height/amount to get the correct height, thats the ~1" tall thin wall of urethane i mentioned & how he cut the tip. my trim installs & sits right, just like it did before it was replaced.

You needed to use spacers & have the right size tip. This is the reason to pay a pro

I always put the sealant on the channel rather than the glass. Can't see a reason not to. If it's on the channel, you KNOW it's in the right place.
On the butyl tape question, I use it on my older cars but i agree with brad900 and I can't remember where, but I was surprised to read somewhere, sometime ago that it was not actually 'butyl' tape from the factory but some other product that I was unfamiliar with. I still use it though.
Interestingly, my 1980 280zx FSM instructs you to put the quarter windows in using butyl tape...by name... So, that's what I did.

Wherever I read what I just mentioned and as I recall it was an online magazine article, also said that urethane was a gov't safety requirement in the early '70s so that the windshield wouldn't go flying out of the car in a crash, not for it's improved water sealing. Don't get me wrong, it's great and once cured, it takes an act of congress, or at least a hot knife, to get it out. For me, I don't put my cars together with surviving a crash much in mind so I use the butyl and never have had a problem. One more observation, on our mid/late '60s cars, the trim has more to do with keeping the glass secure than the sealant. I knew a guy with a '68 hardtop that lost his back glass while flying down the interstate with all the windows down and no trim on the back. He said he stomped it to the floor and 'POOF!'
That wouldn't happen, I don't think, with fully cured urethane.

A pro did install it, through my insurance no less.

I usually do all my glass myself using butyl, but figured I'd use my insurance to replace my cracked windshield.

Hell I've installed 3 windshields/back windows this summer alone, and all 3 have come out perfect using butyl. It's pretty nice buying a few rolls of it and doing it yourself. A hell of a lot cheaper too.

I used 3/8 on the front with non original glass and 5/16 on the back with original rear window, worked just right for height on trim.

Sorry if I am being dense here, this will probably be more apparent when I actually get to installing the glass...but I don't understand how butyl applied around the edge of the glass could be anywhere but in the correct location?


What am I missing (aside from the fact that this is not the "normal" way it is done)?

You're right and I'm sure you won't have any problem doing it that way.

Yah fingahs might stick to the butyl tape ,when you handle it,for the install. And yah might eff up the placement of the butyl.....but what do I know..

Wow...tough crowd tonight...just trying to understand something, not looking for criticism because I'm asking a genuine question.

I'm sure came across a thread somewhere (Chevelle site maybe) where this had been done so was curious.

I was being sincere...not criticizing. It will probably work just as you say by putting it on the glass. I just meant that you have about one inch of metal to put it on in the channel so it's just about impossible to get it wrong there.

Greg.....maybe mrennie was talking to me.....lol

Very possible MUSLCAH...LOL