Butyl for sealing portlights and other questions?

[jhulmer]

I'm sold on BOATLIFE Life-Calk polysulfide based rubber. This is also recommended by Practical Sailor for ports and deck bedding. 4200 and 5200 will seal it for sure but you would play hell removing it later if needed. Life-Calk however is not recommended for plastic.

[Cheechako]

I did my 30 footer plastic portlites and my 31 footer bronze portlites with 5200 years ago. The 31 footer about 35 years ago. I saw that boat (which I built) a few years back. No stains on the ply around the portlites. Yeah... I'll be hated if anyone ever has to take them out, but the stuff is amazing. :>)
I use 5200 on all that type of stuff. Ports, hateches etc. I just rely on it. My motto is "do it once like it will never need to come off again"! haha

[bstreep]

Dow 795 is the caulk of choice. If you have great fasteners to take ALL of the load, butyl tape is the way to go.



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[Lojanica]

Butyl is great because it flexes and does not dry out.. The problem is it is so soft when it gets warm (In the sun at 2 pm in the summertime) that it will squeeze out and then stuff needs to be tighten. Again that's OK if it is contained. I like the 3/16" O-ring on a roll n-butyl material from gasket suppliers. Just put a ring around the outside of the part. Put the Butyl (again 3/16" thick or match the sizes. That is order the same thickness material of both butyl tape and o ring. The o-ring will keep the tape from all squeezing out as the part is tghtened. Also keeps the mess a little contained. In the long run it is worth it. You can use super glue to hold the oring in place until the part is tightened.

Just a thought.

[Paul L]

Originally Posted by Lojanica

Butyl is great because it flexes and does not dry out.. The problem is it is so soft when it gets warm (In the sun at 2 pm in the summertime) that it will squeeze out and then stuff needs to be tighten. Again that's OK if it is contained. I like the 3/16" O-ring on a roll n-butyl material from gasket suppliers. Just put a ring around the outside of the part. Put the Butyl (again 3/16" thick or match the sizes. That is order the same thickness material of both butyl tape and o ring. The o-ring will keep the tape from all squeezing out as the part is tghtened. Also keeps the mess a little contained. In the long run it is worth it. You can use super glue to hold the oring in place until the part is tightened.

Just a thought.

We've had the same problem with butyl oozing out in the tropical heat. I have some ports that still ooze after two years. The stuff gets on sheets and the deck. A pain to clean up.

[Reefmagnet]

The oozing aspect of butyl is a little concern. Existing stainless fittings on deck have oozed over a 18 month period, but the stuff I use never goes gooey enough that it would pick up on, say feet, and transfer. II have removed some fittings previously sealed with butyl recently and, on the upside, I was very impressed with both how much adhesion it actually has (obviously not that great, but impressive for what it is) and how easy it is to clean up using turpentine (mineral spirits) with moderate elbow grease.

[Rainh2o2]

I have an older catalina 25. The windows are notorious for leaking and people have a hard time getting them sealed. I remove my windows and carefully examined the frames and cutouts. Found the cutouts where rough and some fit well to the window frames and others where very sloppy. The plywood in between the inner and outer fiberglass was also dust in all but one window. I replaced the plywood and epoxied it in after trimming the loose cutouts to fit the windows snugly. I then used byutal tape from the RV store and a local hardware . I could buy some really thin stuff from the hardware store to fill in the gaps and spilt frames but found the larger stuff from the RV store better at sealing the the windows to the boat. I put them in on a hot day and took 3 days slowly tightening the hardware down. This allowed the byutal tape to settle and squeeze out. No leaks the first time. Examine the support and mounting areas and make sure the the windows fit the hull well. You can't seal a loose fitting window that has trouble turning down without seal. Think gaskets in an automobile, if you have a dirty or bad fit between two pieces it will never seal properly. I am pleased with the buytal tape.

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