The bottom corners of my windshield frame and upper birdcage were rusted through, and I've welded in new steel in place. The windshield fits well around the frame all except for the lower corners. There is a gap between the glass and the frame of about 1/8 to 1/4" more so on the passenger side. I've cut and re-welded the frame there, but can't seem to eliminate the gap.

Is this something normal for the C3? I've considered using body filler to fill and contour the gap so it's consistent around the perimeter, but I'm concerned that normal flexing and vibration of the frame/window will cause the filler to crack and delaminate from the frame. Anyone else had this issue, what did you do to fix it?

 

Thanks. I know that the windshield needs to stand off the frame, but figured that the contour of the frame and windshield would match so the standoff distance was uniform around the perimeter. It's not with my car. When I put the windshield on the frame (bare, without the butyl), it contacts the frame in all places except the bottom legs and corner.

I could make up the gap with sealer, but would prefer not.

 

IF you have a gap in the area that you repaired an added steel to where the metal was previously rusted.

Do not worry about it...because you SHOULD NOT be using butyl tape to install this windshield....it needs to be installed with urethane.

And if you have an increase in the gap...the added urethane that you can apply will fill in this gap and when it is cured...it will work well.

Keep this in mind if you care to do this job to industry standards.

I would NOT apply any body filler on the surface of the windshield frame that the urethane is going to be applied on in order to bond the windshield to the frame.

The reason for this is the possibly of the body filler shearing off if the car if it gets hit. I have to worry about this stuff due to I am liable for repairs and it can come back and haunt me. If you are doing this on your own car...then do as you wish.

This is also true in making sure that the flat surface that the urethane is being applied on is NOT PAINTED. The possibility of it sheaiing off is also a factor. This is why...that is it best to clean this surface clean to bare steel ( if needed) and apply the specially designed primer to the steel frame. Then apply the urethane to it.

Also there is a special cleaner and primer that is applied to the glass itself where the urethane is going to contact it. This may or may not vary depending on the manufacturer of the urethane that is being used.

I do know some people who will apply a coat of epoxy primer...but do not apply this coat too thick due to if it is too thick..it also can shear.

Corvettes never had butyl tape to install the windshield.

If you choose to use it...that is up to you. But also be aware that there is a special butyl primer that needs to be applied in the frame so the butyl can successfully bond onto.

Because...on the 1973 to 1977 Corvettes....the rear glass is bonded in using butyl tape.

DUB

 

That's a great response, thanks for the advice. What primer would you recommend? I typically treat with phosphoric acid (OSPHO) and follow up with a 2k primer. Is this suitable under the urethane?

 

The term '2K' primer can be taken several ways and be misleading. It is quite a generic term used today and does not actually specify a specific primer itself. Kinda like 'meat', 'beer' or 'juice'....the list can go on and on. Very non specific terms.

I wrote to use the primer that the manufacturer of the urethane that you plan on using wants you to use.

And if you are using a phosphoric acid on the metal...I would advise you to call them on their tech line and find out if phosphoric acid is an acceptable product to use on the steel due to how it can effect the metal and how their primer may or may not adhere properly.

IF I apply an epoxy primer I use PPG's black epoxy primer...but for what you are doing...it would cost so much to buy what you need for such a small area. Unless you can find a bodyshop in your area that will sell you a little bit of it.

DUB

 

ok, thanks. I live less than a mile from the Atlantic and here in central Florida steel has a severely limited lifetime, so I'm cautious what I apply on it. The morning dew and particulates from the ocean turns to dried salt in the sun and back to solution with the dew the following morning...and over a period of time eventually makes its way to the metal. It's amazing how a visually perfectly painted panel eventually seems to rust from the inside out.

 

I understand that. But that is not the issue where the actual urethane primer is contacting the surfaces. THAT is where its adhesion is most important. And what is applied on the metal prior to the urethane is also just as important.

Keep in mind that these products do take into account not all cars are in an area that does not have salt. They have considered this in their design.

Your situation with the salt being in blown into the dew and drying up is something entirely different and that issue will only effect joints where this dew and water can get into...much like Northern cars being driven on salty roads during the winter.

Generally any surface contamination does not effect anything in regards to panel integrity due to it is generally maintained and the salt is not allowed to sit on a car for years and years.

DUB

 

I’ll be having my windshield removed and then reinstalled with new clips and weatherstripping. Any input would be helpful. I’m also trying to get a ides of how many clips I’ll need.

 

What do you mean by "clips" ?