Bonding windscreen

[Paul Bearman]

I intend bonding my windscreen direct to the car without using a rubber finishing strip, just Sikaflex.Has anyone else done this & if so what is the best way to approach it?

Paul.

[Bill Bayard]

Paul,

Sikkaflex is a good stuff, when used according to the manufacturer's instructions.
Go to: www.sika.com for technical details on
which Sika product to use and exactly how to apply.
Remember that no caulk lasts forever when
exposed to direct U/V light.

Bill

[Paul Bearman]

Thanks Bill,

Any ideas as to the clearance I should leave around the screen?, cosidering I am not using a rubber trim.
Any other fitting tips you can reccomend?

Paul.

[DC]

Paul,

You've got mail

David

[Paul Bearman]

Thanks Dave,

Just looked at the info you sent. This is exactly what I have been looking for, clearances etc.

You have mail also.

Many thanks.

[DC]

Paul,

You do have another option. I think Autoglass or other windscreen suppliers would fit your windscreen for you. Not sure what guarantee you would ahve given that they are not supplying the screen.

Is there any one out there who's had one replaced by a third party like Autoglass??

[David Tickle]

Hi
This is my first posting as I'm a a new member here, not quite sure how it all works yet.
I have a KVA and have had Autoglass fit both the front and rear screens. They went in without problem and Autoglass did a good job.
I had to do a lot of preparation of the fibreglass though to get the glass to fit well. Basically the depression into which the glass sits was not deep enough for the glue, glass and rubber surround so I had to deepen it and slightly alter the shape.
All OK now though.
Hope this helps.
Dave Tickle

[91740Gt]

Autoglass do not hold windscreens for 40s. They obtain them when required from Tornado and then add on their horrendous fitting charge with no guarantee as it is a fibreglass body fitment. I fitted my own front and rear screens (no rubber surround) as i wanted flush fitting and after seeing dreadfull workmanship standards by Autoglass operatives.
No problems after all this time. If you do bond screen in your self always do it in two stages, and only after centre section is fully and properly located, thus avoiding the cracking of windscreens that so many people have experienced.
Graham @ GTA/Gulf Racing.

[kent]

did it work with sikaflex ? [img]/ubbthreads/images/graemlins/confused.gif[/img]

[91740Gt]

Whoa there and steady with using Sikaflex for total bonding. I would never recommend the total use of such a strong adhesive for the initial foam strip and holding of the screen, only for the outer final smooth infill. If you ever needed to change your screen the using of sikaflex for every stage of the bond could give you massive headache in making a relatively "clean" non surround damaging removal possible. Sikaflex is a marvellous product but long term can give you "big" problems if you ever have to seperate items bonded with it.
Remember that the screen must have a small amount of "float" to allow for body flex, albeit minimal, thus avoiding edge delamination and cracking.
Regards,
Graham @ GTA.

[DC]

There is a special Sikaflex specifically for fitting screens. I have the reference, which I gave Paul. I have had no problem with mine yet (after two years and 4,000 miles) but you can see the screen flex if any pressure is put on the exposed corners where it meets the doors.

The biggest issue I heard was slight cracks/chips on the edge of the screen which grow. You need to take extreme care not to break the glass on the edges when it is fitted.

[Paul Bearman]

The Sikaflex Dave mentions is:

SIKAFLEX-255FC Primerless Windscreen Adhesive.

[DC]

Paul,

So have you done it yet - bonded in the windscreen? You better be at Goodwood as Frank is giving me a hard time to be there too!!

[Paul Bearman]

Hi Dave,

I will be fitting the windscreen this weekend. I have done a trial run to ensure it will fit correctly & I have the correct clearance around the screen. Although I did have to grind some areas to allow the screen to sit lower in the recess.
All being well & not taking time off for sleep breaks, I WILL be at the Track Day!!
By the way, the welt marks from Frank's whip are clearing up nicely! Joking aside, Frank has pushed me for which I thank him even if it has meant not seeing the kids for 3 weeks & I now have an allergic reaction to sunlight.

Regards, Paul.

[rogerRF076]

I believe it can be done.

I suggest that you go and talk to your local windscreen installer who will be able to explain the requirements for it.

As I understand it:

1. the screen must have a black protective film embodied in the laminate to protect the polyurethane from ultraviolets.

2. Certain adhesives are better than others.

3. The screen should be trimmed to fit and arrassed to smooth off the sharp edges.

I intend to do the same to mine and the above is `what i have been told so far.

I think it would be best to get the local installer to do the job.

Roger Norris
Australia.
RF076

[Howard Jones]

Here's how I did mine. I had my windshield sanded with a belt-sander that glass installers use that has a special belt material meant to sand glass.

I made the size of the windshield 1/4 inch smaller than the windshield opening all the way around. I assume that your windshield fits right at this point. It must lay onto the fiberglass all the way around. NO MORE that 1/16 inch clearance between the glass and the mating surface. Anymore and you risk cracking. The glass must be supported everywhere.

The glass guy who helped me bought the same adhesive that is used on corvette's. I would worry about using the wrong glue. Too strong and you will F.U. the fiberglass trying to get it out later if it gets broken. Fiberglass cars are different than steel ones and there are different adhesives for them.

We taped off the paint all the way around the opening and masked back away from the edge about 6 inches so that we didn't have to clean off the paint if we screwed it up. By the way using the correct amount of adhesive is critical!
Too much, big mess. Too little, won't fill the gap completely.

Applied glue to opening and set glass into it WITHOUT MOVING IT AROUND. The glass must be set in place right where you want it the first time. 1/4 inch gap all the way around. PRACTICE DRY A FEW TIMES TO GET THE TECHIQUE DOWN.

You will only get one try at this!!!!!!

After you have it in place carefully press glass into the opening all the way around with ONE hand. CAREFULLY!!!

Cleanup if necessary. IT SHOULD NOT BE! Let adhesive harden for 24hours inside warm garage. Put heater out there if necessary. 40F overnight temps won't work. Try to get it up to 60F at least. Its best to do this in the summer if you have a choice.

The next day mask off the 1/4 inch gap all the way around on both sides, glass and paint, and fill in the depression with black RTV. Do a nice finish with your finger. Let it get hard again overnight. The reason you use RTV is to keep the UV off of the adhesive in the gap.

The way it looks is directly proportional to the workmanship.

I really think that having a automotive glass man help you is important. But under no circumstances try to do this alone. IT TAKES TWO PEOPLE who WANT to do this. My wife would not do as a helper, I don't know yours. You need a strong man with long arms.

Good luck.

[Bill Musarra]

Paul,
Is Howard implying your wife is manly with long arms [img]/ubbthreads/images/graemlins/lol.gif[/img]
Bill

[Kevin Hodge]

Paul, Kev here. Finish inside with tape, for the goo factor. Sika flex will be a great friend don't be stingy on the tape (inside)

[patbarry]

I am not an expert, but the guys who just did mine said they did not recommend using sealant only. They tossed out the rubber supplied and did a three step process, 1) a rubber trim piece around the fiberglass (very thin), then a primer followed by Dow "Betaseal U-418HV)" urethane adhesive and then the rubber. All taped off right now, they suggested 48 hours to leave the tape on. They said this was the same stuff used by OEM.

For what it's worth...

[Bill D]

That looks really good. Thanks for the tip