Screwfix sealants

[ghostlymoron]

I'm just looking through the screwfix catalogue for suitable sealants for bedding skin fittings. I'm confused, I don't really need an adhesive (especially if I ever want to remove the fitting in future) so what's wrong with a basic silicone sealant at £2.19 a pop?

 

[Bodach na mara]

Silicone is not recommended underwater for a start. Depending on the material of the hull, a polysulphide (GRP hull) or oil-based mastic (wood) are better.

 

[Anthony]

The polysulphide works well when I have used it above the waterline, personally I would pay the £8 for the Sikaflex and sleep at night without worrying about it.

 

[Clyde_Wanderer]

[ QUOTE ]
The polysulphide works well when I have used it above the waterline, personally I would pay the £8 for the Sikaflex and sleep at night without worrying about it.

[/ QUOTE ]

Sikaflex should NOT be used on plastic fittings, especially below the waterline, for this purpose use Lifecaulk.
For any type of metal fittings I use Sikafles 291, which is actually easy enough to get off with a sharp blade when nesseccary.

 

[Clyde_Wanderer]

[ QUOTE ]
[ QUOTE ]
The polysulphide works well when I have used it above the waterline, personally I would pay the £8 for the Sikaflex and sleep at night without worrying about it.

[/ QUOTE ]

Sikaflex should NOT be used on plastic fittings, especially below the waterline, for this purpose use Lifecaulk.
For any type of metal fittings I use Sikafles 291, which is actually easy enough to get off with a sharp blade when nesseccary.
Never ever use silicone below the waterline.

 

[tobble]

[ QUOTE ]

Sikaflex should NOT be used on plastic fittings, especially below the waterline

[/ QUOTE ]

could you expand on this please?

 

[Sheff]

1) Don't use anything from Screwfix, it's not appropriate to marine use.

2) Don't use sikaflex 291, it's a glue, it bonds, like the proverbial to a blanket!......... you may want to remove what you're fixing.

As mentioned by some, you want a polysulphide sealant.......... just means it remains flexible over time and can be removed.

 

[flyingscampi]

Useful reading HERE and HERE

 

[Flossdog]

Northshore have bedded my lifting keel grounding plate with silicon. No watertightness is needed and it seems OK after 8 years. Obviously it might need to come off and if they had used Sikaflex 291, well, it would never come off!

 

[ghostlymoron]

Sheff,
Do you have any product names for polysulphide sealants?