As we sell more closing seals to a world-wide audience I thought it about time to explain how to fit these and how to ensure the correct orientation of the seal (which has an asymmetric section).
If you need other maintenance parts see - Maintenance parts for Lewmar Old Std Ports
Scope
I mention this now as irrespective of the condition of your closing seal the most common source of leaks is actually the section join at 3 and 9 o'clock when viewing from deckside. The focus of this post is the seal but you may well want to tackle the section join at the same time, given the portlight will be out of the boat and on the bench.... I'll return to this later but you can read more in this other blog article - Lewmar Old Standard Openers - known leaks .
Removal
These portlights are clamped against the hull from the inside. Take HUGE CARE removing the ABS trim as this suffers from UV and will likely be brittle. It may be discoloured too, but you can respray these. What you cannot do is REPLACE them as there are NO SPARES. They are usually attached with several short lengths of velcro (12,3,6 and 9 o'clock). With the trim off (and safely stored) you will see a number of machine screws holding the inner ring against the outer frame. Remove these and the inner frame will come away. If resistant try some heat.
The outer frame is now visible and will be only held on by the bedding compound between the frame flange and the hull. The flange is ~12mm so narrow. Have someone inside push a frame end while you try and get a new scalpel blade between the flange and hull. Once started this should come away quire easily. When off clean up the flange to remove any bedding compound (white spirit will help). Release the acrylic by removing the hinge bolts. Pull out the old seal. If you are going to replace the section join (see above) cut this out now and clean the butting surfaces as best you can.
Preparation
You're probably bored with my clean, clean again and go for a third clean, but there really is no point using new silicone to seal against unclean surfaces and particularly those which may have traces of old silicone. It just won't adhere....
When Lewmar built the port and fitted the original seal they will have put a little silicone in the channel at the same time. Not much, just enough to fill the void around the tail of the new seal within the channel. When you now pull the old seal out most of this silicone will remain and the fact that this is now cured (ie no longer liquid) means that you won't be able to push the tail of the new seal in and even if you could there would not be a seal between it and the existing silicone. So the old silicone has to come out, completely....
To add to the challenge the channel is narrow (particularly in the corners) and undercut (to the outward face).
Tools for the job
We make scrapers, mostly from old saw blades (see right), shaping them on a grinding stone. We add a little white spirit as this helps soften the silicone and then we just scrape and scrape and scrape... Ahhh! I hear you shout, 'what about the silicone removers in a bottle'? These don't work, except perhaps on very thin traces, but then white spirit is as good. We've tried loads and none make much of a difference. As an aside.....
'a couple of years ago we took some old frames to a specialist water blasting company.... can you remove the silicone from the channels? we said... No problem, he said.... He tried and tried.... The silicone remained, but it did remove the anodising!!!! Tenacious stuff this silicone.'
The hardest areas are the corners, but you just need to persist and make sure you get it out of the undercut too.
Final clean
Only you can judge whether you've removes ALL the silicone. When you have give the channel a wipe through with Acetone to remove any oily residue from the white spirit (or any other liquids you've been using). It should then look like the photo to the right.
Getting the seal ready
Wipe the tail with a cloth with some Acetone on, just to ensure the silicone will adhere. Now wash your hands and/or put some surgical gloves on. You can find details of the seals we sell and how to order here - Lewmar Old Standard Port Closing Seal
Fitting
First,orientation
No not what you identify as (I was told at the weekend that a local school has had to agree to a young girl wearing a tail to school - apparently she now identifies as a cat (Oh what a mad world...). The Lewmar closing seal a composite of skinned EPDM sponge and solid EPDM (the tail etc). When viewing a cross-section you would note that the solid element is higher on one side and it is this side which needs to be fitted against the aluminium frame. Clearly if we are supplying glued seal hoops you won't spot this difference from the section, but the good news is that you can tell by looking either side of the tail. Under inspection(ie light and a magnifying glass if visually challenged like me) you will note that there is an indentation running along the seal on both sides ( a sort of crease) and you want the side where this is highest (away from the tail) as shown on the left above. This is the side which should be positioned closest to the frame. The more rounded edge, as shown on the right image should be facing the acrylic. Simples...
Second, trial & seal
To start with try a dry fit, just to be familiar with how to push the seal tail into the channel, particularly around the corners (as the channel tends to be narrower here). We use a wooden block to push the seal and a pallet knife to help the tail enter the channel. Then, when ready, put a trace of silicone (preferably CLEAR) in the channel all the way round before finally pushing the tail in and working around the frame. Not too much silicone as otherwise the seal may pop out again further down. Even up the tension now, while the silicone has yet to set.
We then place the old acrylic (if being replaced on the seal and weight this down. Do NOT be tempted to reattach the hinges and clamp the pane down at this stage because the frame section join is weak (when not in the boat) and will bend.
Third, that section join
If within scope, first wait until the seal silicone is set. Then squeeze in some new BLACK or GREY silicone into the section join on both sides before wiping away any excess with a suitable flat tool (or a piece of plastic). Allow to set.
Refitting
Replacing the acrylic
There's some more tips in my previous blog article - Replacing a pane in Lewmar Old-Standard Opener
The inner handles are screwed into the outer button plastics. You will need to prise off the caps in the centre of the inner handles (a Stanley knife works well) to access the screws. When transferring these to a new acrylic, don't forget to change the outer button O ring (supplied) and put on a trace of silicone grease or similar. The hinges bolt on.
DO NOT ATTEMPT TO CLOSE THE ACRYLIC AT THIS TIME!!!!
The section joins are weak and like a fish out of water will not take kindly to you trying to force the latches closed. For this please wait until the port is safely secured back in the boat when the hull will provide the rigidity required.
Rebedding the portlight
We strongly recommend the use of 10 x 3mm GZ tape as this is ideal for the 12mm flange, is no mess and will ensure you have that important 1mm of bedding compound left after you've applied some of your Mr Atlas training on the securing machine screws. You could use the goo (ARBOmast BR) but it will be messy and you'll probably squeeze too much out.... For more information see - Bedding options - Tape, goo and combinations
Now and only now, you can close your acrylic and admire your work. If feeling very bullish you could also spray the outside with a hose and either congratulate yourself on a job well done or wish you'd agreed to pay us to do it. Just saying....
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