Plonk Posted June 21, 2017 Report Share Posted June 21, 2017 Hi All My portholes are currently fixed in place by woodscrews, through the side of the boat and into mdf porthole liners with oak faces. I guess this is not normal practice? The liners are mostly salvagable, if a bit soft now. I am re sealing and re-fitting with fitting 4mm nutserts to screw the portholes too with brass machine screws. They were not very tightly fitted before! Previously, they were (almost) sealed with clear silicone, but I was intending to re seal them with Everflex 145 butyl sealant (from a mastic gun). It is quite soft and gooey, but the data says it never hardens, allows movement (5%) and can be painted over. Is this stuff good enough, allowing for future removal , longevity etc? has anybody else any experience of it? It would have a fairly thin but wide layer in the joint. Abour 1/2 mm I guess. Pat. Link to comment Share on other sites More sharing options...
ditchcrawler Posted June 21, 2017 Report Share Posted June 21, 2017 20 minutes ago, Plonk said: Hi All My portholes are currently fixed in place by woodscrews, through the side of the boat and into mdf porthole liners with oak faces. I guess this is not normal practice? The liners are mostly salvagable, if a bit soft now. I am re sealing and re-fitting with fitting 4mm nutserts to screw the portholes too with brass machine screws. They were not very tightly fitted before! Previously, they were (almost) sealed with clear silicone, but I was intending to re seal them with Everflex 145 butyl sealant (from a mastic gun). It is quite soft and gooey, but the data says it never hardens, allows movement (5%) and can be painted over. Is this stuff good enough, allowing for future removal , longevity etc? has anybody else any experience of it? It would have a fairly thin but wide layer in the joint. Abour 1/2 mm I guess. Pat. Have a read of this thread Link to comment Share on other sites More sharing options...
dmr Posted June 21, 2017 Report Share Posted June 21, 2017 I assume you are proposing 4mm brass bolts into thread inserts into the steel cabin sides? 4mm brass bolts just wont be strong enough to compress whatever sealant you use, even m6 brass is a bit marginal. Can you drill and tap the cabin sides to take m6 directly? I have tried butyl tape for sealing portholes but was not impressed, the stuff you mention looks better, and certainly better than silicone, but I reckon that making neoprene gaskets is the best approach. ..............Dave Link to comment Share on other sites More sharing options...
ditchcrawler Posted June 22, 2017 Report Share Posted June 22, 2017 15 hours ago, dmr said: I assume you are proposing 4mm brass bolts into thread inserts into the steel cabin sides? 4mm brass bolts just wont be strong enough to compress whatever sealant you use, even m6 brass is a bit marginal. Can you drill and tap the cabin sides to take m6 directly? I have tried butyl tape for sealing portholes but was not impressed, the stuff you mention looks better, and certainly better than silicone, but I reckon that making neoprene gaskets is the best approach. ..............Dave I used 5mm brass screws when I did mine, if I do them again I will use 6mm tapped straight into the steel. I used this stuff to seal them Link to comment Share on other sites More sharing options...
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