Butyl Tape Yet Again

[Blue Eyes]

Is butyl tape recommended for Lewmar ports?

For Beckson ports I would use Dow 795 or similar. The trim rings glue on and require a little more "glue" than what butyl can offer. I generally dislike silicone but with Beckson ports polyurethanes and polysulfides can leech the plasticizers out of the plastic and make them brittle prematurely.. There are some uses on a boat for silicone and Beckson ports are one of those areas..

I am reinstalling my Lewmar aluminum fixed ports and planning to use Dow 795. Would butyl tape be a good option for Lewmar ports? The ports are tightened using machine screws through aN aluminum backing plate into the port frame but the screws would have to spin in the tape. Is there temperature limitation to install with butyl tape? One downside to the Dow sealant is the temperature must remain above 50 degrees F for the 21 day cure period which may not happen before I want to launch this year.

 

[Maine Sail]

I am reinstalling my Lewmar aluminum fixed ports and planning to use Dow 795. Would butyl tape be a good option for Lewmar ports? The ports are tightened using machine screws through aN aluminum backing plate into the port frame but the screws would have to spin in the tape. Is there temperature limitation to install with butyl tape? One downside to the Dow sealant is the temperature must remain above 50 degrees F for the 21 day cure period which may not happen before I want to launch this year.

Yes that will work. You just want a good butyl cone around the machine screw. If the port is properly sealed no water would even get to the screw.

The warmer the temp the easier to compress the butyl. There is no temp limit other than when colder it is a little more "dense" and harder to compress. Butyl never cures so there is none of the "must remain above 50F for 72.55567 hours, with no precipitation, no direct sun, humidity not to drop below 48%" etc...

Lube the aluminum threads with Tef-Gel and tighten SLOWLY over multiple days, a little at a time, until the butyl stops oozing out and the port is tight to the hull sides. DO NOT over tighten or you'll risk stripping the threads. Allow it to displace out at the speed it wants. This can take a couple of weeks in colder temps but is easy to do..

When your screws begin to feel "snug" stop tightening and wait a couple days. When you come back you'll get a couple more turns, do the same, repeat until oozing stops..... To speed the process you can use a hair dryer to warm the butyl.

 

[Squidd]

What Kind of Windows are These..?

I don't have a Hunter, but now I'm getting confused on different bedding for different windows...?

I have plastic non opening windows that leak, should I use butyl or silicone or some other sealant on these...??

I plan on pulling the interior screws, splitting the window, sealing on outside (butyl?) and squeezing them back....Am I on the right track?

I had asked this in another section and didn't get an answer, so I'll tag it in here... as I see we're talking about different kinds of windows and sealants...

 

[Maine Sail]

I had asked this in another section and didn't get an answer, so I'll tag it in here... as I see we're talking about different kinds of windows and sealants...

For plastic framed ports I'd use Dow 795

For bronze, stainless or aluminum framed ports it is okay to use butyl..

 

[tkanzler]

The large lexan 'ports' on my Hunter 340 leaked badly after 12 years. I tried a number of fixes, and none worked. Not usually even for the first rain.

I asked here, and I asked Hunter, and the answer was Dow 795. Hunter recommended against removing the large port (single piece) that looks like a windshield unless absolutely necessary, so since it was still well bonded but leaking from two locations, I cleaned out the joint perimeter using the solvent Dow recommended (really made the old stuff soft, and fast), cleaned it thoroughly with the same solvent, masked, and filled the joint. Worked beautifully for the two or three seasons I had it until I sold it.

Lessons learned included not wasting time with half fixes, using the right material for the job, and to put more faith in what folks say here, especially when they'd learned the same things the hard way.

Butyl tape from MS is on my shopping list for the deck hardware I need to rebed this spring. Using tried and true methods. No shortcuts. :dance:

 

[SVTatia]

Tightening screws with butyl

When your screws begin to feel "snug" stop tightening and wait a couple days. When you come back you'll get a couple more turns, do the same, repeat until oozing stops..... To speed the process you can use a hair dryer to warm the butyl.

Maine Sail, I will reinstall my ports this summer... they are thru bolted. I will only use butyl and no other sealant as you suggested in another forum. Questions:

Tightening the screws until snug, then stop -- do you recommend covering the portlight with plastic in case it rains because the "joined parts" may not be totally watertight yet or just a bit of tightening will seal it already? Also, to clean-up: what to use and do you wait until it finally stops oozing?
Thanks

 

[Dantodd]

Do you remember the solvent they recommended and about how Deeply down did you go into the old seal? I am going to try this method on my old dead lights and will be happy to get 3 years out of them. They are pretty crazed so I will be replacing the, in a few years.

Hunter recommended against removing the large port (single piece) that looks like a windshield unless absolutely necessary, so since it was still well bonded but leaking from two locations, I cleaned out the joint perimeter using the solvent Dow recommended (really made the old stuff soft, and fast), cleaned it thoroughly with the same solvent, masked, and filled the joint. Worked beautifully for the two or three seasons I had it until I sold it.

Butyl tape from MS is on my shopping list for the deck hardware I need to rebed this spring. Using tried and true methods. No shortcuts. :dance:

I just ordered some butyl tape from MS too. I could have picked it up cheaper but might as well support the man who taught the lesson.