Which Sealant for Raymarine thru’ Hulls

[Wandering Star]

Today was spent removing 2 old transducers and enlarging the holes to take my new Raymarine (Airmar) transducers.

Which sealant would it be best to use for the purpose of bedding them in - hopefully nothing too exotic as I need to swing by a chandlery and buy a tube tomorrow.

 

[Boathook]

I use arbomast br butyl for all my fittings above and below the water line.

 

[jlavery]

When I fitted a new transducer last winter, the boatbuilder friend who helped me recommended and used Sikaflex. Has worked really well.

 

[PetiteFleur]

I also use Butyl tape for sealing fittings as Boathook mentions - also for bedding window frames etc.

 

[bignick]

Thru hulls are critical.
Use Sikaflex or another good quality adhesive sealant.

 

[waynes world]

All of the above also Puraflex 40 from Tool station is much same as the Sikaflex 291i. Butyl in gun or tape. Just dont squeeze to much out of what ever you use so as to leave a gasket. Once nipped down let set then nip up a little more. a mm gasket is good.

 

[tillergirl]

Thru hulls are critical but are service items. Not an annual service item of course but when an old one is replaced (as now) Sikaflex 291i is a problem:

R e m o v a l
Uncured Sikaflex®-291i can be removed from tools and equipment with Sika® Remover-208 or another suitable solvent. Once cured, the material can only be removed mechanically. !

Polysulphide is ideal under the water - Arbokol is one product, there is a Puraflex version as well. It bonds very well, seals very well and when the item is replaced, removal is feasible without damaging the substrate - wood or GRP.

 

[Hacker]

Butyl isn’t suitable for underwater critical fittings.

 

[Lightwave395]

Unless you're wealthy 'swing by' Screwfix or Toolstation....

I've used Puraflex 40 or OB1 and my boat is still afloat

 

[Wandering Star]

Thanks for all the advice, I’ve decided to use Sikaflex 291i. I’ll be dead or in a nursing home before they’ll need any maintenance so remember bing them will be someone else’s headache!

 

[superheat6k]

I always use Sika 291i. Also once the tube is opened it will keep fresh in the freezer for months, and an added bonus it will always annoy SWMBO !

 

[dankilb]

Unless you're wealthy 'swing by' Screwfix or Toolstation....

I've used Puraflex 40 or OB1 and my boat is still afloat

I agree and use both (plus CT1) extensively. However, it is worth nothing that PU40 (pure polyurethane) isn’t the same as OB1/CT1 (hybrid polyurethane - similar to 291). There are practical differences, and I tend to go for the hybrid for below the waterline, although I couldn’t specify what difference it would actually make for the average boat job.