Best sealant for rebedding deck fittings

[LeonF]

As my engine is being rebuilt, the boat is now out of the water and it's turning into a major refit. I am re bedding the u-bolts that anchor the shrouds and wonder what you guys think is the best sealant ? I am wary of Sikaflex as if I need to remove them again in the future they may never come out without destroying the deck. Dow Corning flexible sealant ? Something similar from Evo Stik from B & Q ? Or something else ? Thanks

 

[zambant]

I use arbomast br - have done for years
Its a non setting butly rubber
Regards
John

 

[Fantasie 19]

I use arbomast br - have done for years
Its a non setting butly rubber
Regards
John

Yeah - I'd use butyl tape..

 

[laika]

291 isn't so grippy that it'll destroy a structurally sound deck when you pull those u-bolts out. I wouldn't hesitate to use it (in fact it's what I used for that very task last year). I see the argument for butyl with things which you might not want to force or can't get leverage on (e.g. aluminium window surrounds) or for stuff you need to remove and replace frequently but this application doesn't fall into those categories. I used arbormast for the first time this year for a fitting I need to remove regularly and think it's nasty messy stuff to use, though I see the utility.

Cue the fans of CT-1 and Tec 7 suggesting alternatives

 

[Poignard]

Cue the fans of CT-1 and Tec 7 suggesting alternatives

I suggest CT-1

Available from:

Deben Build Base Ltd
Address: Selsdon Rd, South Croydon CR2 0EA
Phone:020 8681 2911

 

[nigelmercier]

I am re bedding the u-bolts that anchor the shrouds and wonder what you guys think is the best sealant? ...

I would use Sikaflex 291, or similar.

On a related topic, I need to do a similar job for the chainplates on the shrouds and the inner forestay. How does one go about it without the whole lot crashing down?

 

[mrming]

Another +1 for butyl tape. Have bedded several fittings with it this year. No leaks, and when two had to come out temporarily when the cabin striping was being replaced, there was no messy adhesive to clean up.

 

[vyv_cox]

This myth about Sikaflex 291 being so strong that it cannot be removed is just that - a myth. In my opinion it is by far the best sealant for the vast majority of purposes but it is never so strong that it cannot be removed. I have even used it for aluminium framed windows and removed them several times without damaging them.

I have used hybrid sealants of the CT1 type, they have their advantages, underwater sealing being one, but nowhere near the strength or ability to flow over threads and flanges that the PU types have. I have used butyl tape on large windows, where it is excellent, but it cannot possibly seal threaded connections. Butyl mastic is also good in its place but I suggest that a heavily bolted joint or flange is not one of them as the butyl continues to extrude over a long period. I did one window with it and have been re-trimming the extruded blobs for a year.

 

[rivonia]

I would ONLY ever use CT-1

 

[VicS]

On a related topic, I need to do a similar job for the chainplates on the shrouds and the inner forestay. How does one go about it without the whole lot crashing down?

One at a time ????? Use a halyard as temporary support if/when necessary