How to seal bolts below the water line

[rogerthebodger]

As has been said early in the thread cur a countersink/chamfer where the bolts go through on both the inside and outside.

This allows for a slug of sikaflex to seal the bolt and washer without squeezing too much out.

 

[vyv_cox]

There was a long discussion on this recently. I think the concensus was tighten immediately then leave it alone.

Yes, that's what I do. Shrinkage of Sikaflex and other PU sealants is minimal so I see no benefit in waiting. Probably another relic of times when we used natural products for such jobs.

 

[ghostlymoron]

It was I that suggested the countersink (not my original idea of course) but I only do it on the outer (water) side. If it's done properly, there's no need for a seal on the dry side although I guess it does no harm.

As has been said early in the thread cur a countersink/chamfer where the bolts go through on both the inside and outside.

This allows for a slug of sikaflex to seal the bolt and washer without squeezing too much out.