Window sealant

[Markhunter1097]

During my covid quarantine on the boat, I finally took off the painted bronze port lights, got them stripped and polished to a mirror, two were chromed to match others Ild done earlier.
All new laminated glass as well
My question it what sealant to use, butyl is no good as it doesn’t hold the glass weight, and previously I’ve used a recommended product that just went to dust.
What do I use that will hold the glass while it dries and wont go to dust?

[Tupaia]

https://www.nfk.com.au/29_dash_4000/...Sausage/pd.php


Comes in cartridges too.

[tkeithlu]

Butyl tape, as opposed to butyl per se, gets recommended frequently on the forum, and I like it. But, I'm not sure I've got your situation clearly in my mind. Is the glass not held by the frame, such that you are sealing it, not supporting it, with the tape or glazing compound?

[Bill O]

Mark,
We used Dow 795 (structural glazing/watetproofing sealant) for our hatches and has held up for more than 10 years. Would think it would work to adhere your glass to the port frame also.
Attached is a link to a Dow construction sealant guide to read to see if it may work for your application.

[Markhunter1097]

Originally Posted by tkeithlu

Butyl tape, as opposed to butyl per se, gets recommended frequently on the forum, and I like it. But, I'm not sure I've got your situation clearly in my mind. Is the glass not held by the frame, such that you are sealing it, not supporting it, with the tape or glazing compound?

The glass actually sits in a rebate in the boat, those frames are just screwed on the inside and cover up the glass edges. Could probably do without the frames, but need them to cover ugly bits, they also used to open but I’ve removed that option for these ones

[Bill O]

Originally Posted by Markhunter1097

The glass actually sits in a rebate in the boat, those frames are just screwed on the inside and cover up the glass edges. Could probably do without the frames, but need them to cover ugly bits, they also used to open but I’ve removed that option for these ones

That even sounds like a better candidate for the Dow 795 structural silicone.

[GJori]

DOWSIL 795
sealed my hath glass 8 years ago looks like new.

[Rumrace]

I would use Lexel. Clear. It’s better than any marine seating goo. Many of which come out of solution in short order from UV.
Level comes in 3 sizes in clear at home depot or on line. Looks like silicone acts like Epoxy with memory. To set unlike materials together I’ve never used never used anything stronger.

[sailasia]

Originally Posted by Rumrace

I would use Lexel.

I am interested in this idea instead of dow 795 which says ±50% Joint Width Movement.
Lexel claims 400% joint movement.

Do you know anyone else who has used this? How long has it been with no issues? Can this be the holy grail?

[bstreep]

2 choices:


1) If you have a mechanical attachment, use butyl tape. The screws/bolts hold it tight & sealed.


2) If you are looking for a "glue"/sealant, Dow 795. It's used for skyscraper windows. DO make SURE you check the expiration date. It's absolutely critical for this stuff. Don't ask my why I know.

[GordMay]

Originally Posted by Rumrace

I would use Lexel. Clear. It’s better than any marine seating goo...

Lexel appears to be an elastic co-polymer rubber sealant/caulking, not a structural [glazing] adhesive/sealant.
Sashco “Lexel”
➥ https://www.sashco.com/wp-content/up...l_TechData.pdf
➥ https://www.conspecindustries.com/wp...3/03/lexel.pdf

[Emmalina]

+1 for dow corning 795 fantastic stuff having tried the rest.

[s/v Jedi]

I recommend using 3M VHB tape to stick the glass to the flange, then use Dow Corning 795 to seal the edges. This is pretty much bullet proof.

[Rumrace]

Unlike Gord cut n paste masterful in depth discounting 10 second evaluation, I’ve used lexel. Lexel demonstrated with a water truck in some state by “ glueing” a 2’ diameter cast iron water tank bottom cover with out the dozen bolts. It’s an sealant which grips unlike surfaces. Has an amazingly memory as heat or cold move surfaces about.
Let’s review how many “ bedding “ compounds get wet and come out of solution. A rigid adhesive may be a mistake.
lexel advertise marine and RV right on the tube.
So I’ve been using Lexel on boats for over 20 years and they have improved the white. The clear takes for ever to Yellow and still stays stable. It’s not silicone chalk. Removing lexel knife.

[Rumrace]

Dow recently had a sealant failure. Was written up in that over priced digital magazine where advertisers don’t have their way with us. The gist of the article was the product came out of solution and became “ sticky”. It went on further to suggest the cause was UV. Then end result was in a very short period the product failed and it’s a leading marine product