Topic: Using 3M Strip Caulk to Seal Windshield

[drummingrocks]

Some of you may have seen the series in Mustang Monthly where Jerry Heasley purchased a stalled '68 convertible project.  Basically, all the parts were there, and the car was already painted and ready to be reassembled.

I saw the update in the most recent MM issue, and they showed pictures of the windshield installation.  I was surprised to see that the installer used 3M strip caulk instead of the more commonly used Bedding & Glazing compound.  I've tried several times on various cars over the years, and no matter what I do, I can't get a windshield to seal completely with the Bedding & Glazing compound.  I always end up with water leaks (some worse than others). 

I was wondering what everyone thought about using the strip caulk approach.  It doesn't really show much of the installation process in the article, but I'm assuming that surely they didn't just leave the caulk by itself; surely they used a caulking gun and something designed to fill the voids under the gasket.  Again, I just thought that was an interesting approach, and was wondering if anyone had successfully used it on their car.

[CharlesTurner]

The current version of 3M strip caulk is very sticky and gooey.  It might hold up ok, never tried it.  Only thing I would be worried about is out in hot temperature/sunlight, the strip caulk may flow out and get a little thin.

On the bedding compound, I have also had challenges with getting it to seal, the thing I do is work the material down between the frame and glass with a narrow plastic tool.  Apply more beads of compound for a final smooth finish across the whole frame to gasket.  There also needs to be sealer between the glass and gasket, I cut a small angled tip on the glazing compound tube tip to get between the glass and gasked and run a small bead.

[drummingrocks]

The current version of 3M strip caulk is very sticky and gooey.  It might hold up ok, never tried it.  Only thing I would be worried about is out in hot temperature/sunlight, the strip caulk may flow out and get a little thin.

On the bedding compound, I have also had challenges with getting it to seal, the thing I do is work the material down between the frame and glass with a narrow plastic tool.  Apply more beads of compound for a final smooth finish across the whole frame to gasket.  There also needs to be sealer between the glass and gasket, I cut a small angled tip on the glazing compound tube tip to get between the glass and gasked and run a small bead.

Thanks, Charles.  That sounds like the method I've used too with the Glazing Compound.  On my last installation, I did use urethane between the gasket and the glass (though NOT between the car body and the gasket), as seen here: 

I really thought that would work, as it seemed like the urethane would completely eliminate the chance of leaks between the glass and gasket.  On the car I tried it on, both the windshield and back glass are still leaking.  In fact, on the rear windshield, I ended up putting so much glazing compound in the rear window channel that I couldn't get the lower stainless molding to snap into place ('67 coupe).

[CharlesTurner]

I share in your frustration, seem to have had pretty good luck on the last few cars using my method though.

Haven't used urethane as it dries hard and tough to get off if needed.

[drummingrocks]

I share in your frustration, seem to have had pretty good luck on the last few cars using my method though.

Haven't used urethane as it dries hard and tough to get off if needed.

From what I learned from that video, using urethane between the gasket and the windshield glass is acceptable.  It would be a nightmare (at least for the next person to take the glass out) if you used it anywhere that actually came in contact with the car body.

[67gtasanjose]

Yeah...I don't look forward to sealing a VINYL TOP car when I get to that point.

Anyone with pointers on that job? My understanding is first the headliner is in, then the vinyl roof layed in over and around the rivets for the moldings and THEN WHAT? Fill eveything till it flows out everywhere? (white roof, it sounds REALLY messy!)

[drummingrocks]

Yeah...I don't look forward to sealing a VINYL TOP car when I get to that point.

Anyone with pointers on that job? My understanding is first the headliner is in, then the vinyl roof layed in over and around the rivets for the moldings and THEN WHAT? Fill eveything till it flows out everywhere? (white roof, it sounds REALLY messy!)

It sounds like a nightmare.  I've never done one, but it seems like a vinyl top would just be one more source of aggravation.  And geeze, if it's a white top....I feel for you there.

[CharlesTurner]

Taping as much of the vinyl top around the opening will help minimize the mess.  Bedding compound usually comes right off with some mineral spirits though.

[Brant]

Here's a Blog post with pictures that I posted a while back.  Click on the link or the picture.

http://blog.virginiaclassicmustang.com/2013/02/65-68-mustang-windshield.html