Sealing the Windshield

[jaredyates]

For folks that have reached the final windshield installation phase, what measures have you used to seal it from rain leaks?

[Mark Goldberg]

I like the 3M stick caulk. You see it on a lot of certified planes as well. Mark

[Erbman]

Believe it or not, I did nothing! I have a formed-in-place fiberglass fairing around the base of the windshield with many screws. The fairing is NOT bonded to the windshield I think I once found a small air leak somewhere but it is so small I don't notice it unless I go looking for it. The one time I flew it in any significant rain was on the FISK approach into Oshkosh. By the time we landed, there was maybe a tablespoon of water that had leaked through. Strangely there were more water drops in the cockpit after the airplane sat in the rain, again at Oshkosh.

Since I live in the desert and try to avoid flying through rain, I'm not too interested in trying to seal it any better. Also since the easiest access to the back side of the instrument panel is to remove the windshield and remove the boot cowl, I'm not interested in anything that would "glue" it in place or make it harder to remove. I might be interested in a caulk that does not permanently bond to the parts, but I haven't taken the time to look for such a thing.

My suggestion would be to start out without applying any sort of caulk or sealant. You can always go back and apply sealant later if you find your conditions make it necessary.

[Enewton57]

I used Black Silicon indoor/outdoor caulking made by GE. Masked off the windshield leaving a 1/4" gap then loaded the caulk in pressing it into the gap with my finger. Used a rag with mineral spirits to clean my finger. Pull the tape while its still wet. I did the same with the skylight and aide "D" windows. The blck gives a nice clean proffessional look in my opinion.

[Battson]

If you live in a dry climate, you can do nothing! If you live somewhere wet, you probably need to do something. Your instruments will thank you for it.

We used a thread of caulk along the top and bottom edges - caulk is nasty to work with an you can see the finished product, so you have to try and be neat - not easy. It can be disolved with MEK, but this can also react with paints/fabric covering system etc so be careful... This option makes removing the windsheild more of a chore. We used rubber weatherstrip up the sides, with the doorpost cover over the windsheild, trapping the rubber against the acrylic. The screws holding the sides in place have nylon washers, as do all the screws in the fairing strip - making them watertight.