Ray Posted May 16, 2019 Share Posted May 16, 2019 I'm assuming that the screws holding the handrail to the roof go into wooden blocks beneath the grp I have discovered several screws are not biting and obviously need to fix this. Is there any method of doing this that does not involve taking down the internal ceiling? I have a close boarded and varnished ceiling! Any tips for securing from above gratefully received. The rail overall is not loose but over time may well become so with regular use. Quote Link to comment Share on other sites More sharing options...
Vaughan Posted May 16, 2019 Share Posted May 16, 2019 Whatever else you do, you must make sure that the screw holes are properly sealed, or water will get in, rot the "sandwich" in-between the two GRP mouldings of the cabin top, and then you have really got trouble! It is critical to get the holes the right size for the self-tapping screws, as if the hole is too small, the screw will crack the gelcoat and if too big, the screw will not hold. If this is the result of damage you may need to do a GRP repair first. If not try using thicker screws, but always use plenty of mastic in the hole first. 1 Quote Link to comment Share on other sites More sharing options...
Ray Posted May 16, 2019 Author Share Posted May 16, 2019 Thank you, I can't see any damage but there is certainly a route in for water so I need to get on this soon! Will start with thicker screws and mastic, hopefully this will be enough. Quote Link to comment Share on other sites More sharing options...
Smoggy Posted May 16, 2019 Share Posted May 16, 2019 I am assuming this is into grp here! Before using mastic I would be tempted to clean the holes with a drill marginally bigger than the existing hole and run epoxy down first making sure there are no air bubbles underneath the epoxy (poke a thin wire into it a few times to get any air out), allow to cure then drill smaller and use self tappers. A bit of neat epoxy first to 'wet up' then a bit of thinly bulked epoxy to give a bit more structure for the screw to bite into. Once you go down the mastic route it will need to be thoroughly cleaned out before you can fill the hole, not an easy task with mastic, by all means use a little bit on the thread once the hole is filled and drilled to seal. 1 Quote Link to comment Share on other sites More sharing options...
oldgregg Posted May 16, 2019 Share Posted May 16, 2019 What's the best sealant to use on screw holes for external fittings such as this? I know silicon will end up drying out and cracking, but not sure what a better product is. I guess Plumber's mait would do the job but I know there are products which are better and easier to work with. 1 Quote Link to comment Share on other sites More sharing options...
annv Posted May 16, 2019 Share Posted May 16, 2019 I find Geocel 201 works well or any car gasket rubber sealant if a small tube will do, don't tighten fully until it's cured and make sure surface/hole is clean/ dry and any loose material is removed, if wood core is rotten dig out and DRY out and then use Gorilla past but smear screw threads with vaseline otherwise you won't be able to remove/unscrew in the future. John 1 Quote Link to comment Share on other sites More sharing options...
OldBerkshireBoy Posted May 16, 2019 Share Posted May 16, 2019 Plumbers mait (mentioned earlier) will always stay as a putty if used under the rail mounting points but doubt if boat builders use it tbh.The problem with silicone is if it doesn`t work then you have to remove all of it which can be a lot of hassle removing the last little bits. Whilst far from being a boat builder I`m thinking along the lines of removing screws and let the holes dry out completely then fill with grp epoxy and drill new holes as said above. 1 Quote Link to comment Share on other sites More sharing options...
Vaughan Posted May 16, 2019 Share Posted May 16, 2019 1 hour ago, Vaughan said: If not try using thicker screws, but always use plenty of mastic in the hole first. Perhaps I didn't make this clear. What I meant was that you can try a larger screw in the hole and if it holds, you can take it out again and apply mastic to seal the hole and the screw. If it needs a repair you can always fill with Isopon P40, which is a filler re-inforced with chopped strand matt, and then re-drill when it has hardened. But again, seal with mastic when you finally apply the screw. 1 Quote Link to comment Share on other sites More sharing options...
Ray Posted May 16, 2019 Author Share Posted May 16, 2019 Thanks again, and thanks for everyone's answers. Now I have a clear plan of what to do and how to do it. At first I feared I would have to take down the ceiling from inside! Quote Link to comment Share on other sites More sharing options...
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