Deck fittings sealant.

Capt. Clueless

Capt. Clueless

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Going back a lot of years, when I was building Leisure 17's, we used a flexible mastic before fitting deck fittings and nutting up. I am going to be removing a few deck fittings on my Guy Thompson renovation to "re-seat" again instead of just going round the outside with a sealant. What is everybody using these days as a bedding mastic please?
 
I bedded some stanchions on butyl tape off a roll, the type of stuff your local double glazing guy uses. It is very clean and non- sticky in use.
Your confidence level will be zero as most of it squeezes out of the joint and it generally looks feeble. Still, it seems ok so far and it is well spoken of on this august forum.

I am going to try it on my shroud U bolts which I am apprehensive about, we shall see.

PS

There are a number of U Tube videos on the theme eg:

https://www.youtube.com/watch?v=A4m2EvjTZ5Y&t=16s
 
Last edited:
doug748 said:
I bedded some stanchions on butyl tape off a roll, the type of stuff your local double glazing guy uses. It is very clean and non- sticky in use.
Your confidence level will be zero as most of it squeezes out of the joint and it generally looks feeble. Still, it seems ok so far and it is well spoken of on this august forum.

I am going to try it on my shroud U bolts which I am apprehensive about, we shall see.
Click to expand...

I've got something similar as a hatch sealant (It's called hatch sealant);) Only that is black. I will need white or as near as.
 
I favour butyl rubber for deck fittings. It does not come in a tube, you just tear off a small amount. It moulds like a mastic, easy to clean up round a fitting and is non-setting. Available in black and white.
 
I fitted a new forehatch and used white butyl tape which comes in various widths and thicknesses. I used 3mm thick which
took up the slight curve in my foredeck. It peels easily off the backing and you can cut small shaped pieces for awkward corners etc. I bought mine off eBay and there are various suppliers.
I have found that I make a mess with stuff from a gun.
 
Is sikaflex 291i suitable as a sealant for such work? I need to fix a stanchion base on my boat. It goes through the deck and there's a bolt inside the boat. I need to ensure that water cannot run under the stnachion base and through the deck which it does now. Basically any gap between the "bottom screw" of the stanchion and the hole on the deck must be completely sealed.
 
ditchcrawler said:
I have found that I make a mess with stuff from a gun.
Click to expand...

That is something I did want to try and escape. I would prefer a hand pliable product, so when I'm standing in my tender doing a fiddly bit, and the Windermere tourist boat comes round at full chat, there isn't gunge still coming out the end of the tube and going everywhere whilst I hang on. I also have never been the neatest of workers with a caulking gun & tube.
 
cmedsailor said:
Is sikaflex 291i suitable as a sealant for such work? I need to fix a stanchion base on my boat. It goes through the deck and there's a bolt inside the boat. I need to ensure that water cannot run under the stnachion base and through the deck which it does now. Basically any gap between the "bottom screw" of the stanchion and the hole on the deck must be completely sealed.
Click to expand...

The Butyl sealant is good, but if you only have a central bolt i'd use Sikaflex, it's not only a good sealant, but it will stick the base down too.
 
Capt. Clueless said:
That is something I did want to try and escape. I would prefer a hand pliable product, so when I'm standing in my tender doing a fiddly bit, and the Windermere tourist boat comes round at full chat, there isn't gunge still coming out the end of the tube and going everywhere whilst I hang on. I also have never been the neatest of workers with a caulking gun & tube.
Click to expand...

The butyl in a cartridge is a really good sealant, but it does have a tendency to get everywhere. You most certainly won't want to apply it with your fingers, or a stick.

Tip for anyone using butyl in a cartridge, automotive panel wipe cleans any mess up very nicely. It won't attack plastics like acetone does and it also cleans up silicone and a host of other messy substances.
 
Capt. Clueless said:
I've got something similar as a hatch sealant (It's called hatch sealant);) Only that is black. I will need white or as near as.
Click to expand...

Forget about the colour. Only the edge of the sealer is visible and even if originally white will go dirty after a short while. Black in fact gives an attractive line around fittings and doesn't discolour.
 
You can squeeze as little as you like out at a time using a gun. Just got to release the pressure in the tube each time.

Sikaflex also comes in small toothpaste size tubes, easier to apply using fingers like that. Pricey that way though...
 
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