Re-sealing stanchion bases.

[SeaStu1]

I need to re-seal 3 stanchion bases as they are letting in water. I can get access to the nuts underneath by removing some trim. I imagine that it is a case of loosening off everything then using plenty of sealant before putting it all back together. I've never done this job before so would welcome any advice and tried and tested methods and materials. Thanks.

 

[Georgio]

Remove stanchion base, clean off any old sealant, a good squirt of sealant to the stantion base (Sikaflex is good for this) put back in position, add some sealant to the top of the thread of the bolts/machine screws, put in bolts, add washers and nuts from inside. Do up nuts (may require assistant on deck) but don't do up tight, just enough to squeeze the sealant out a bit leaving up to 1mm of sealant between base and deck. Clean up the sealant (baby wipes are really good for sikaflex). Once Sika has cured it gives you a nice rubber gasket, nip up the nuts an bit more (try not to disturb the position of the bolts/screws) and go sailing

 

[Deleted member 36384]

I have been following the advice below and stopped automatically going for Sikaflex which is OTT if it's the adhesive type:-

http://www.pbase.com/mainecruising/rebedding_hardware

So far I have bedded: coach roof grab rails, fore hatch, window frames (16) and the sockets for the Bimini frame. None are leaking, no waiting on setting, just make up.

Worth a read at least, food for thought.

Regards,

BlowingOldBoots

 

[LittleSister]

If your deck has a balsa or foam core you should also seal the intervening hole through the core between the two layers of GRP with epoxy (if this hasn't been done previously) before replacing the stanchion or other fitting as decibed above.

 

[ianfr]

I have been following the advice below and stopped automatically going for Sikaflex which is OTT if it's the adhesive type:-

http://www.pbase.com/mainecruising/rebedding_hardware


Worth a read at least, food for thought.

BlowingOldBoots

+1

Ian

 

[Nicholas123]

I need to re-seal 3 stanchion bases as they are letting in water. I can get access to the nuts underneath by removing some trim. I imagine that it is a case of loosening off everything then using plenty of sealant before putting it all back together. I've never done this job before so would welcome any advice and tried and tested methods and materials. Thanks.

Take out the bolts.clean out the holes & smear with Vaseline.Job done.

 

[Talulah]

I quite often don't use a bedding compound like Silkaflex anymore but instead make a silicon gasket out of 3mm Silicon sheet.
Silicon sheet is expensive but it avoids having lots of partly used Silkaflex tubes going off.
The Gaskets are easily made with scissors or Stanley Knife. Any bolts passing through then I drill an undersized hole in the gasket. I have found this solution far more effective in a lot of cases.

 

[oldsaltoz]

Have any idea why they are loose or leaking?

What sort of material/s do the bolts pass through and how many.

What sort of backing plate or washers are installed.

With the above information you will get a more informed answer, rather than just general advice that may not be correct for your set up.

Good luck and fair winds.

 

[Neeves]

I quite often don't use a bedding compound like Silkaflex anymore but instead make a silicon gasket out of 3mm Silicon sheet.
Silicon sheet is expensive but it avoids having lots of partly used Silkaflex tubes going off.
The Gaskets are easily made with scissors or Stanley Knife. Any bolts passing through then I drill an undersized hole in the gasket. I have found this solution far more effective in a lot of cases.

Put the Sika, or equivalent sealant, in the deep freeze - it last not quite for ever, but a long time.

Jonathan

 

[TimBennet]

Have any idea why they are loose or leaking?
What sort of material/s do the bolts pass through and how many.
What sort of backing plate or washers are installed.
With the above information you will get a more informed answer, rather than just general advice that may not be correct for your set up.

Good points. Why has the sealant failed? Is there movement between the stanchion base and the deck? Does the deck flex?

To really stop stanchions leaking they must be rigidly mounted to a rigid base - the leverage on the top of a stanchion is incredible. So the deck must be solid, and may need a gusset between the hull and topsides. In some situations, for instance where a racing crew use the stanchion to pull themselves out the cockpit every time the boat tacks, you may need a bracing leg on the stanchion.

But once the mounting area of the deck is secure enough, you then have to mount the stanchion. Slightly over-drill the bolt holes and fill with epoxy resin and high density filler (or metal plastic padding). Make sure the deck itself and the base of the stanchion are both flat. If the deck is not flat, level it with a 'square' of high density filler moulded from the stanchion base. Drill the bolt holes undersize and tap them for the threaded fasters. Bolt the stanchions down hard with PU sealant.

Any highly loaded fittings such as winches, cleats, line stoppers and stanchions will never stay watertight if there is any movement possible by compressing the sealant. They must be mounted rigid and then there's a chance the sealant will block any remaining gaps, as you're only asking it to do this one, simple job.

 

[Talulah]

Put the Sika, or equivalent sealant, in the deep freeze - it last not quite for ever, but a long time.

Jonathan

No freezer on board. Seriously though. If I kept it at home I would end up continuously buying new tubes such would be my planning.
One of the reasons I now prefer silicone gaskets is because it guarantees a thickness of silicone sealant.
When using tubes of Silkaflex the temptaion is to squeeze most of it out when tightening up the fitting.
With something like a stanchion base you need the thickness to absorb the movements.

 

[SeaStu1]

Thanks for all the replies. I can only assume that wear / tear and age is the cause of them failing and there is evidence of the previous owner having problems but never really curing the problem.

 

[Boathook]

I use arbo mast br for fittings now. Also in a previous thread on bedding fittings, slightly counter sink the holes to allow the sealant to gather around the bolt shaft. Also other comments about the deck being balsa cored is important as unless correctly reinforced leakage will occur.

 

[jag22]

I did loads of research on this when I took mine off for repair and replaced them. I used Butyl tape, got it on a roll off eBay. All you need to do is take off the base (get someone below deck to help). Countersink the hole in the deck, put a small amount of butyl around the bolt, drop it into the stanchion base, then put more tape around the bolt so that when you place it back into the hole in the deck, the tape will ooze out and make a seal. Do a bit of searching on this and you'll find some good examples. It's really easy and works perfectly. No need for sikaflex in my opinion for through deck fittings.