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Hi all,
I am about to install a new windshield gasket on my '66 F250. Are you guys using sealer? I think the factory installed the windshield without sealer, but I am planning to use CRL7708 between the cab and the gasket and a Polyurethane windshield adhesive between the glass and the gasket.
Any reasons that this is a bad idea or other product recommendations?
I would not use a polyurethane, or any "adhesive" in either area. You don't need a bond as new windshields do. You just need a waterproof filler in the gaps. As you hinted above, you could even use no sealer, however, you will have water leaks. Use a non-hardening compound such as the 3M non-hardening bedding and glazing compound (#08509) shown. After installation, you want the gasket to be able to move and seat slightly to compensate for any variation in accurate fit. (Remember these were designed in the 50's and 60's) Use the same compound in the slot that the glass slips into and into the groove between the windshield opening and the gasket. The 3M product will make a heck of a mess when you install and pull your rope, however, it will seal well and the excess on any surface will clean up with rubbing alcohol. That will just take a little time. For a pull rope, use nylon parachord, not too thick, but strong and lubricate the rubber generously with liquid soap/water or hand cleaner (not the kind with the pumice in it).
What Resonateur said. Don't get creative, 8509 is all you need. Do get all 4 corners of the seal over the pinch weld before you start pulling the rope. That will center the windshield in the frame. If you have the stainless trim be sure it is all the way into the seal and use plenty of masking tape to hold it all together until it is installed.
Long time auto glass shop guy here... 3M Bedding and Glazing worked good in the past but it changed 10+ years ago and now it will dry out and shrink, causing leaks later on. We had to switch because of multiple come backs for leaks, we'd pull the glass out and the sealer was dried up and no longer doing it's job. We did a windshield job on a '66 C10 that a local shop recently finished restoring, they used a tinted windshield and installed it with Bedding and Glazing. The owner didn't like the tint so we changed it out for a clear windshield, when we removed the tinted glass (installed within the last year or so) the sealer was very dried out and cracked so it's still a problem. Now we use Dekaseal 8936 in black, it's a million times easier to clean up and it doesn't dry out over time. Let any excess dry/cure for an hour or two and it sticks to itself, so once you get a small chunk of it you just go around the edge and dab it off. Takes maybe 2-3 minutes to completely clean off any that squeezes out. Once it dries it has the consistency of butyl.
Astronaut...thank you for the information and update. I have used the 3M product several times without any issues, however, it has been several if not many years. I would put a lot of weight on what the glass pro's have to say. I did like the non-drying feature, which it sounds like, may no longer exist. I think the principle is the same with either product as far as where to place it and how to install.
Yes, Dekaseal applies the same way as Bedding and Glazing, it just actually stays pliable and doesn't shrink/crack later on. You can sometimes get by without sealing between the glass and rubber, but only if the rubber is made correctly (iffy these days) and the glass is the same thickness as the groove in the rubber (iffy these days). We've been getting a ton of windshields over the last few years that are significantly thinner than the originals making the groove too narrow to seal on the glass correctly, so we've been sealing that as well. Between the glass being thinner, not always being shaped or sized correctly, and the lack of consistency in gasket quality its difficult for even us to get a windshield in and fitting correctly sometimes. We've had to buy three different glasses on some jobs before we got one that fit. We've found that its best to use setting blocks around the pinchweld and dry fit the glass without the seal to make sure the windshield size and shape matches the opening before trying to install it with the gasket.
Long time auto glass shop guy here... 3M Bedding and Glazing worked good in the past but it changed 10+ years ago and now it will dry out and shrink, causing leaks later on. We had to switch because of multiple come backs for leaks, we'd pull the glass out and the sealer was dried up and no longer doing it's job. We did a windshield job on a '66 C10 that a local shop recently finished restoring, they used a tinted windshield and installed it with Bedding and Glazing. The owner didn't like the tint so we changed it out for a clear windshield, when we removed the tinted glass (installed within the last year or so) the sealer was very dried out and cracked so it's still a problem. Now we use Dekaseal 8936 in black, it's a million times easier to clean up and it doesn't dry out over time. Let any excess dry/cure for an hour or two and it sticks to itself, so once you get a small chunk of it you just go around the edge and dab it off. Takes maybe 2-3 minutes to completely clean off any that squeezes out. Once it dries it has the consistency of butyl.
