5200 - no flex and you'll never get it apart intact later.I found a few leaks in the chain plates, and I am well versed in the repair of those from my MacGregor 25. For those I used 4200 and it worked great.
Yes I have the Aluminum framed windows and I have a couple leaking from the rubber seal (glass is wet along the seal/glass joint) and a couple that are leaking at the hull interface (no water on the glass but a dribble from under the frame). Why not use the 4200 on the frame to hull interface? I know the 5200 is a no-no due to how hard it gets it is a very permanent fix, and I don’t want that. I also know about the silicone… I have dealt with that for 30 years worth of fixing cars/trucks/motorcycles and what have you where people have “fixed” this or that leak with the stuff and only ended up making a mess and a more difficult repair. And usually the correct fix was cheaper than the tube of silicone.
I have a roll of the stuff I got when I worked at an auto part store that was returned with a couple feet missing. The boss told me to refund the guy anyway (he was a Ken) and just toss it because we couldn’t resell it. I took it home to throw it away… I just haven’t got it all tossed out yet. It’s too useful for many many things around my shop.I used butyl for one of my windows. If you put too much on you'll never get all of the extra to squeeze out, at least, not during the initial installation. As a result of using too much butyl (one layer of tape wasn't thick enough, two layers turned out to be too thick) The window frame stuck out further than the others and I occasionally find butyl oozing out two years later. The stuff is great for rebedding deck fittings but not windows
I used flex seal and my port windows no longer leak. Um, that means ventilation is reduced so make sure you have a good de-humidifier.Ok, so now that Luna has been cleaned up, I’m starting to find where some of the leaks are. And windows are one of them… or 8 of them. So where can one get new replacement rubber to fix 40+ years of sun and age?