Sikaflex 291

[MJWB]

Any advice please? Someone has told me Sikaflex 291 is okay to use underwater. The website refers to marine applications but not specifically submerged in seawater.

If not, any thoughts on what is? I'm thinking I might have to cut and remove through hull studs on a hull anode and assume new ones will need to be bedded in sealant or such like.

 

[Tranona]

Suggest you use a non setting sealant such as butyl or polysulphide as easier to remove in the future, although Sika 291 will be fine

 

[Rhylsailer99]

Any advice please? Someone has told me Sikaflex 291 is okay to use underwater. The website refers to marine applications but not specifically submerged in seawater.

If not, any thoughts on what is? I'm thinking I might have to cut and remove through hull studs on a hull anode and assume new ones will need to be bedded in sealant or such like.

i used sikaflex 291 on new anode bolts but afterwards i epoxied the 1st securing nut and washer to the hull on the inside to be 100% sure, i also used sikaflex 291 on 4 through hulls so i hope its ok .

 

[VicS]

Any advice please? Someone has told me Sikaflex 291 is okay to use underwater. The website refers to marine applications but not specifically submerged in seawater.

If not, any thoughts on what is? I'm thinking I might have to cut and remove through hull studs on a hull anode and assume new ones will need to be bedded in sealant or such like.

You can use 291 but it's an adhesive sealant.
ITYWF that Arbokol 1000 is the recommended sealant. It is a polysulphide like Tranona suggests.

In the old days we would have used Sealastik, which was just like ordinary window putty in a tube ....... It's still good on my through hulls after more than 40 years

 

[ithet]

Any advice please? Someone has told me Sikaflex 291 is okay to use underwater. The website refers to marine applications but not specifically submerged in seawater.

If not, any thoughts on what is? I'm thinking I might have to cut and remove through hull studs on a hull anode and assume new ones will need to be bedded in sealant or such like.

Interesting post. Sikaflex 291 is now slightly reformulated and branded as 291i. As the OP says the Sika website and datasheet does not state use under water and also refers to it as an "interior" sealant and for "professional use" only. Other websites selling it do say for use on underwater fittings. I have new through hulls to fit, will probably stick with Puraflex 40 which I have used before.

 

[VicS]

Interesting post. Sikaflex 291 is now slightly reformulated and branded as 291i. As the OP says the Sika website and datasheet does not state use under water and also refers to it as an "interior" sealant and for "professional use" only. Other websites selling it do say for use on underwater fittings. I have new through hulls to fit, will probably stick with Puraflex 40 which I have used before.

Another polyurethane adhesive sealant similar to Sikafex 291 ... Made by a Sika group company too

 

[superheat6k]

I hope Sika 291 is OK - all my skin fittings and anode bolts are bedded in the stuff - never had one leak yet, and very very tight when trying to remove something. I can live with that.

I used to use Boatlife Polysulfide, but no longer available and Sika is the main product for this task in Force 4 my local chandlers.

If you end up with half a tube unused the stuff stores very well in the freezer for many months, although it does annoy SWMBO.