pp000830

I was reading all the stories about rust perforated windshield channels do to water pooling in the gutter under the black rubber edge molding. If let go it seemed to be an expensive invasive fix.

I went to the DIY store and purchased some:
Locktite Roof & Flashing polyurethane roofers black sealant,
for calk gun application.

I first slipped a air nozzle under the rubber molding and blew out the channel under the molding edge with a little air. If one doesn't have a compressor a can of camera dust-off will work well.
In my case no moisture blew free indicating things were already dry. If your car proves to be wet, blow it out the best you can and let it sit in the sun for a day or two and check again.

Starting at the top center I lifted the molding with a plastic narrow spatula and slipped the nozzle of the calk gun vertically directly into the gutter. With the rubber molding in-place it simply stretched out of the way.

As the sealant was pumped in it oozed out indicating the channel was full. I pumped the sealant in as I work my may around one side of the window to the center bottom. It helps to support the nozzle with your free hand as at times it wants to bend. Slow down and make sure the channel completely seals in the lower corners where a surprisingly large amount of sealant will fill before overflow.

I then began at the top center and worked my way around the opposite side of the car to the bottom center.

It took an entire tube of sealant to complete the job indicating a rather large air space is under the molding on these cars.

I then used multiple rags to wipe the excess sealant from the car and molding. I then went over it again with a clean rag wet with mineral spirits to pick up any small amount that was left on the glass, molding, paint and where the edge molding meets the body paint.

I had done this previously to the rear window with good results a few months ago.

Ideally the above should be done on a clean rust free channel shortly after a new windshield has been installed. I suspect that even if your car has corrosion in the bottom of the gutter but has not progressed to perforation this process will slow down the steady march of corrosion if not stopping it dead in its tracks. Unlike other methods to fill the channel the above completely fills the void and has extremely good adhesion to both sides of the channel drying to a hard rubber consistency.

Hope others find this posting useful,
Andy

gonzilla

Interesting. You see any potential downsides to doing this?

EMBPilot

well, for one, its not compatible with the windscreen sealant.

Gbos1

I wouldn't... just my 2 cents.... . . .. . .

pp000830

Can you elaborate on this as my understanding is that urothane sealants have been used used for years as automotive glass sealant and Urothane is also the base resin on 2K automotive auto paint.

Andy :-)

orangecurry

Why not? It's a Porsche TSB.

9501 from memory.

I did it in 2010.

http://www.orangecurry.com/993/screen-sealant/

EMBPilot

I dont think the porsche TSB is directing the use of consumer grade roofing compounds, that are typically not compatible with butyl or silicone based products. but thats just me.

orangecurry

I agree you shouldn't pump any old thing in there, but you seem to making a few assumptions on what the owner has chosen, and then stating it's not compatible, and then stating it's typically not compatible.

What's the composition of Bostik 6050?

user 723923490

I am intrigued by this approach however I have 2 concerns;
1) the choice of the material being used to fill the gap
2) the cleaning & prep of the gap before hand
The material must remain flexible and be able to adhere to the substrate otherwise water will be allowed to work its way underneath.

mike cap

There are several excellent and professional DIY's on prepping and filling the rear channel that specify the correct product to use and that incorporate the Porsche TSB procedure. Do a search here or pm me and I can send you the link to the Rennlister that did a superb DIY.

orangecurry

Thanks that's very kind of you.



Oh, and is it Groundhog Day?

https://rennlist.com/forums/993-foru...ar-window.html

pp000830

We shall have a follow-on discussion in the event of my needing to replace the windshield or back light some time in the future and I can see how effective using the urothane sealant was.

Having worked with engineers in automotive manufacturing one of the reasons a silicone may be specified in the TSB has to due with the gassing out materials. I suspect volatile organic compounds used as solvent in the stuff I used is an EPA no-no in large scale automotive manufacturing and therefore would never be recommended in a TSB.

Then again larger volume body shops are forced by the EPA to use water based acrylic paint something when applied in the aftermarket will not last the life of these cars.

Much like modern washing machines that save water due to government regulation but do not adequately clean cloths and smell like BO when they sit is because engineers were forced to meet requirements unrelated and in contention with the primary function of the product. Ultimately the risk of not using the recommended sealant product falls to me, not one of the bigger risks in my life.

All in good fun!

Andy :-)

Pichu

Andy has a fan, whenever he posts, embpilot has to disagree no matter what he says.

EMBPilot

umm its printed on the roofing sealant itself. im not questioning the Porsche compound

EMBPilot

not really dude. just pointing out so noobs dont go jamming roofing sealant into their cars, thats all. i could care less how he butchers his own car, its the "advice to others" that should really come with a warning sticker.