Why is everyone stuck on Dow 795 When Cars use this?

[Chotu]

These products are what is used to hold car windshields in place.

Why are all boat people stuck on Dow 795 then, when there are proven, existing products for bonding glass to moving vehicles?

https://www.3m.com/3M/en_US/company-...3242009&rt=rud

https://www.dupont.com/products/betaseal.html

I can’t understand why all these half a dozen or so stationary construction minded glazing products are so recommended on this forum and throughout the boating world are suggested when this stuff has been properly holding windshields in cars for decades and never leaks, never comes unbounded, never reveals its existence unless you smash a windshield and have to replace it.

Seriously questioning the collective wisdom on this one.

Did some guy use 795 once and it spread like a rumor?

Who here has used industry standard windshield bonding adhesives? Anyone?

I’m blown away these products aren’t in the discussion when we talk about glazing on moving vehicles

Note: My glazier (4.9 stars on google maps, over 1000 reviews) said my mistake was using Dow 795 on polycarbonate in the sun. That it was the Dow 795 or ANY silicone was the incorrect method that caused the problems I had with the large windows. He suggested an entirely different adhesive for polycarbonate.

[longjonsilver]

i use windshield adhesive to hold on various moldings on my car. They have never come off... Can't say about boats tho, however it seems marine anything is overpriced and under performing.....

jon

[Dsanduril]

Not the first time this discussion has come around. https://www.cruisersforum.com/forums...ml#post2776416

Leopards apparently used to use Betaseal and found it wasn’t UV stable (seems difficult given that cars spend a lot of time in the sun, but there you go). They switched to Sika 295 12 years ago.

Will be interesting to see where this discussion goes.

[Chotu]

Originally Posted by Dsanduril

Not the first time this discussion has come around. https://www.cruisersforum.com/forums...ml#post2776416

Leopards apparently used to use Betaseal and found it wasn’t UV stable (seems difficult given that cars spend a lot of time in the sun, but there you go). They switched to Sika 295 12 years ago.

Will be interesting to see where this discussion goes.

That is an interesting point.

The frit should be protecting the glazing adhesive from the sun entirely in the installation instructions I’ve been reading today.

Other moving vehicles (cars) will often use what they call a dam in the instructions to lead water away from the underside of the windshield. It’s often made from foam. Otherwise you could also use any UV stable sealant that can take the movement of the vehicle.

The glazing adhesive is not used to the edge where light hits it. It’s not used as a sealant. It’s used as an adhesive below the frit only and far away from the sunlight.

So if leopard had it out in the sun, they didn’t apply it correctly.

My mind is literally blown reading about these products after all the debates on here regarding glazing products.

The funny part where I knew my glazier really knew his stuff is he said 795 with polycarbonate windows my size in the South Florida climate will last only 6 months. That’s exactly the amount of time I got from it. Exactly.

I’m changing my problem windows (ones that undergo the worse thermal expansion in direct sunlight) to glass to give all adhesives a fighting chance.

[sailortype]

I tried it, sounded like a good idea. Yes it works well (subject to the above)... but the stuff is seriously mucky and hard to control. If you get it anywhere on the fiberglass, it will be stained FOREVER. Nothing will take off the stain short of sanding and regel.
Never again.

[Emmalina]

Old discussion but Dow does not require primer and has 50% elasticity and is UV stable in a nut shell !

[rbrentp]

The previous threads led me to using both the marine grade butyl tape and then a 795 bead. Some of the Plexi is five feet long. Two years and not a drip in the Florida sun and wind. All exposed to sunlight, no visible deterioration.



From an adhesion standpoint, I would have to believe it was improper prep. From a sunlight perspective, no guesses, hasn't been a problem.

[Scubaseas]

The 3M stuff needs a primer which is epoxy based. It also will stain gelcoat or fiberglass badly.

[Gaia]

Originally Posted by Chotu

These products are what is used to hold car windshields in place.

Why are all boat people stuck on Dow 795 then, when there are proven, existing products for bonding glass to moving vehicles?

https://www.3m.com/3M/en_US/company-...3242009&rt=rud

https://www.dupont.com/products/betaseal.html

I can’t understand why all these half a dozen or so stationary construction minded glazing products are so recommended on this forum and throughout the boating world are suggested when this stuff has been properly holding windshields in cars for decades and never leaks, never comes unbounded, never reveals its existence unless you smash a windshield and have to replace it.

Seriously questioning the collective wisdom on this one.

Did some guy use 795 once and it spread like a rumor?

Who here has used industry standard windshield bonding adhesives? Anyone?

I’m blown away these products aren’t in the discussion when we talk about glazing on moving vehicles

Note: My glazier (4.9 stars on google maps, over 1000 reviews) said my mistake was using Dow 795 on polycarbonate in the sun. That it was the Dow 795 or ANY silicone was the incorrect method that caused the problems I had with the large windows. He suggested an entirely different adhesive for polycarbonate.

What did he suggest for polycarbonate?

Jim sv GAIA

[Chotu]

Originally Posted by Gaia

What did he suggest for polycarbonate?

Jim sv GAIA

He said it way too fast. I’ll get it out of him when he comes to look at putting glass on my replacement windows and share with everyone once I find out.

I didn’t want to sound like a tire kicker since he’s very busy and is coming an hour out of his way to do the preliminary inspection and measurements for my new glass windows.

[glcalahan]

Following

[tamicatana]

It is quite disingenuous to denigrate the common wisdom and especially the product.

In the prior thread, and indeed on the label itself, directions were given that the OP did not follow. Please be sure to peruse the OP other threads before passing judgment on the statements made.

[j.g.evans]

I used an auto store auto window glazing compound on bolted in place acrylic (smoky grey) ports and had problems. It stayed soft and leached out around the edges, perhaps due to cleaning compounds. Caused black stains. I replaced it with 795 with no problems. Manufacturer recommended too.
Don't use Lexan. The sun will glaze so you can't see through it in a few years. The strength and impact difference with acrylic is negligible.

[seabreez]

Originally Posted by Chotu

That is an interesting point.

The frit should be protecting the glazing adhesive from the sun entirely in the installation instructions I’ve been reading today.

Other moving vehicles (cars) will often use what they call a dam in the instructions to lead water away from the underside of the windshield. It’s often made from foam. Otherwise you could also use any UV stable sealant that can take the movement of the vehicle.

The glazing adhesive is not used to the edge where light hits it. It’s not used as a sealant. It’s used as an adhesive below the frit only and far away from the sunlight.

So if leopard had it out in the sun, they didn’t apply it correctly.

My mind is literally blown reading about these products after all the debates on here regarding glazing products.

The funny part where I knew my glazier really knew his stuff is he said 795 with polycarbonate windows my size in the South Florida climate will last only 6 months. That’s exactly the amount of time I got from it. Exactly.

I’m changing my problem windows (ones that undergo the worse thermal expansion in direct sunlight) to glass to give all adhesives a fighting chance.

In Canada here, I use Flextra or Supra. It is a window sealer / caulking for windows and doors. It flexes very well, flexible, seals and is easily removable and is good in cold and hot climates. To remove, simply grab an end and start pulling slowly and will lengthen like an elastic and free itself at the same time. Very good stuff for my usage!!

[Mlp48]

I'd be interested in any new sealant but would worry about a sealant being too hard to remove like some polyurethanes. The popular hatch repairer in Norwalk, CT is the 1st place I'd heard say, "We use nothing but 795..-- and you should too". I've sent a number of hatches there and they come back looking great but the sealing material has eventually failed. The charge to re-condition with this service is not inexpensive but they do a very thorough with it, replacing the lens too. It has sometimes been as cheap to buy new hatches when they can be found on sale. To be fair, the hatches I've sent most often for repair are SS-framed and Chinese and these do get very hot, in my case, from having sliding light blocking shade tightly closed -- which makes the space between hatch glass and slider an "oven" or one very hot space. This is in the MidAtlantic to Northeast. In the Tropics, exterior hatch covers are often more sensible to worry about any new sealant.