Making good a leaky seal around portholes

[alex_rhind]

The seals on my Lewmar saloon portholes are leaking in two places (about 100mm). I have located the leaks, will remove the algae/mould that's collected on the external seal edge.

Given the Stikaflex (GRRRR- see previous post) that's been smeared in some places, this is an ongoing problem I have inherited on buying this 10-year-old Moody.

Short of replacing the porthole, what's the 'cure'? How do you make good a porthole seal? (It's not the casing that's the problem, by the way.)

 

[eyupdougdown]

I would remove the porthole, clean off any residual sealant from any attempts previous, leave to dry, rough up surfaces with some 240 grade wet n dry, clean surfaces with some sort of degreasant, leave to dry, squeeze sikoflex onto boat in nice fat worm all the way around (centrally) where porthole is to seat. Place porthole in position and SLOWLY press it down onto the sealant. Using new fasteners, tighten each one in turn bringing the porthole down onto the sealant which should have now squeezed out of the gap. Once satisfied that it is firmly secured, wipe off any surplus sealant with a scraper. Clean the area up with a cloth and degreasant - something like acetone - use gloves for this part. Leave the hatch overnight before going near it again. That should do the trick. Sound about right? I'm sure there are difffering views but that's wot i'd do. I dunno.

 

[Evadne]

That's pretty well what I did on my windows, white spirit will get sikaflex off before it has set. I reseated the glass in sikaflex too, which was the source of the problem. Its not a hard job, all things being equal, but very messy. The advantage of sealant over new rubber channel is that if there is a little corrosion channel letting water through, the sika will fill it up nicely.

 

[BlueChip]

What you need to do is this.
Remove the porthole and hook out all the old sealant on both sides of the glass using a scrapper and hooked wire. Clean the slot thoroughly.
With the porthole laying flat and the glass resting on the lower side of the frame, squeeze Sikaflex in on the upper side of the glass only. You can mask the frame and glass as you wish but clean excess of as it cures

When this seal has cured, turn the porthole over and put as large a weight on the glass as you dare so it compresses the Sikaflex and opens a gap on the upper side under the frame. Squeeze Sikaflex into this gap. When it cures remove the weight and you will have a water tight seal.

 

[Boathook]

I have rebuilt windows (toughened glass in aluminium frames) using Arbosil 1096 that comes in black. This product is used by Houdini Marine Windows so they told me. Hopefully it will work just as well as sikaflek but will come apart if the need arises