Metan-Ettan. Fixing leaking portlights
During the first winter after I bought Meritaten I was struggling to remove portlights’ frames - to clean them from old chrome and to properly varnish wood under them.
The struggle was due to used sealant - polysulphide, in this case brown Sika. This thing has its place on any boat but one needs to remember that not only is it a sealer - it is also a decent glue!
Putting Sika under anything which needs to be periodically removed for maintenance is asking for trouble. Especially on wooden boat.
This devil is holding so strong that you may tear it out together with wood underneath.
It was then that I sworn to myself to never use it under any metal-to-wood interface on my boat.
All deck and cabin metal accessories need to be removed during boat maintenance. Some of them yearly (like portlights), some of them less often.
Due to very different thermal properties of metals and wood one needs to seal the interface between them. Best if the seal is also acting as isolation. The thing is that due to temperature changes there will be condensation under the metal which, if trapped, will then slowly deteriorate wood underneath.
My predecessor in Meritaten’s history had glued portlights with Sika, in hope that he will never again will have to remove them.
Wrong!
Moreover - since wood screws holding brass frames to the cabin were not doing their job, it was really only Sika which held the assembly together. Screws had no holding power to strongly pull the metal frames towards the wood.
I don’t like that: not seaworthy at all.
Even though polysulphides are almost ideal moisture barrier the evil properties of water enable it to creep under anyhow. It’s just a matter of time.
Not a big deal if you notice that as a leaking portlight - then you know it’s there and leak needs to be fixed.
Worse if the place cannot be inspected - water then does its job constantly for years, slowly turning wood into pulp and rot.
Off went Sika (sharp knife!) and, after varnishing, I’ve sealed the interface with Ettan.
Now - Ettan is a name of the product which is local to Scandinavia. It’s a mixture of bee wax, pine tar, linseed oil and… that’s it.
It smells smoke and is used to seal small leaks. It’s also used as a wooden boat perfume, giving it a scent of nostalgia.
Apart from smell, the nice thing about Ettan is that it is constantly sticky, never dries out, it’s natural and can be re-used countless of times. Just scrap it from the surface, melt with hot air and you can use it again. It can also be easily cleaned anytime with turpentine.
Try that with Sika - nope!
The only way here is to cut it and them mechanically remove.
Ugly job.
The only disadvantage of Ettan is that it melts on sunny day. Like bee wax.
If used above waterline, in exposed areas, it will melt.
If it is confined in a cavity - no big deal, it will solidify at night, filling the cavity even more tight and repelling water even better. Tar present in the mixture is rot inhibitor.
However - if there is a possibility to leak outside - it will.
That has happened under my portlights, resulting in voids under the brass frames and causing leaks which I was fixing constantly during last, extremely hot summer.
I’ve changed old screws to new, longer brass screws. They held a bit better but still not enough to force all parts to fit nicely.
Now came the time to fix that better. Sika again? No, not yet.
I’ll try a combo of Ettan and rubber gasket.
I’ve cut out 1mm rubber gaskets for each portlight frame. Pre-drilled the rubber to accommodate new, M4 machine screws which will go all the way through cabin sides.
My theory now is that Ettan deployed on the wood and around glass (plastic in fact) will seal the wood and prevent condensation to build on top of it. Rubber gasket on top of that, held tight with metal frame and thru-screws will prevent Ettan from leaking out during hot days.
And if I spot a leak I can first try tightening the screws to compress the gasket, hopefully sealing the assembly.
To be proved next summer.
So today I’ve cleaned roughly rests of the last year’s applied Ettan and re-applied it again, sealing the wood. Then went assembly of rubber and metal, tightened firmly with screws.
On the inside I’ve used closed nuts to match the interior and not spoil aesthetics with exposed threads.
I think it turned out very nicely.
We’ll see if it works as expected but at least it is now seaworthy.
Interior before drilling thru-holes for M4 screws
After portlight frames removal - most of Ettan is gone, exposing voids waiting for rain water
Re-applying Ettan
Half-way sealed. It’s a messy job but smell is good!
Hot-air gun helps keeping Ettan in workable consistence.
Brass washers and closed nuts on the inside. Matching nicely with copper-riveted frames