Sealant recommends for Skin Fittings

[Marceline]

Hello - it's another very basic newbie question, but from our survey there was a recommend to reseal a hull skin fitting for the galley sink hose that is a bit loose

Could anyone recommend a good sealant to get that would work in salt water conditions?

For the other sink fitting (from the heads and which was lower towards the water line) they also recommended replacing the plastic fitting with a bronze/DZR and including a valve. I've found some bronze fittings online that look like they could work, but I've no idea what to try and get for the valve fitting.

Any suggestions would be very welcome

 

[Clancy Moped]

Sikaflex®-291i

 

[Marceline]

marvellous - many thanks

 

[waynes world]

Puraflex 40, half price of 291i and as good. used it for many years. Or Butyl in tape or cartridge. For fittings i use stainless steel, always.

 

[RJJ]

You can also use epoxy with colloidal silica for the skin fittings. The minor advantage over sika is (depending on the alignment of your ball valves and hoses) you won't move them accidentally if you are heaving on a stiff valve handle or hose tail. With epoxy, they ain't budging, and if you ever want them out you'll be using grinders and the like.

But most people use sika or pura (which is the same stuff, cheaper) and get along fine.

If you are resealing an existing fitting, do make sure it's really clean of the previous gunk. I would be tempted to replace, it's only a tenner or so.

Many of us including me have used the Trudesign system, where you get skin fittings and ball valves and hose tails all made of FRP (basically, what your boat is made of). I would swear by them and they have excellent instructions. Trudesign also recommend either a polyurethane sealant or thickened epoxy.

 

[Rappey]

I fitted a new plastic through hull for a new electro magnetic log a few years ago.
Used ct1 as so many rave about it. Wiped my finger around the exterior of the fitting as one does and smoothed it to the hull.
One year later the overspread was completely unstuck . ?
Lesson learnt, under the water stick with sikaflex as it does what it's meant to.

 

[Marceline]

Cheers so very much - lots of great suggestions and thanks to you all

 

[Tranona]

Salt water is largely irrelevant as it should never get near the sealant. Two broad choices. Polyurethane sealant adhesives such as the CT1 or Sikaflex. Disadvantage can be difficult to remove. Non setting sealants such as Butyl or Polysulphides which are more than adequate as sealants but easier to remove.

For fittings DZR is fine. You will need a shin fitting, ball valve and hose tail, probably 1/2" or 3/4" for sink drains. Any chandler will stock them - just make sure you ask for DZR.

 

[john_morris_uk]

Our local chandlers often has a choice of bronze or dzr. Alternatively ASAP supplies will send you everything you need (next day delivery if you want). Register for a trade account to get things slightly cheaper.
FWIW I’ve recently added five skin fittings to our boat. Mostly in bronze bedded on Sikaflex.
Tips: Use a ply backing plate inside the hull to spread the load of the skin fitting. I use a hole saw to cut out the circular pads but you could use a jig saw. Round over the edge. I coat mine in epoxy
Use a lolly stick or similar to scrape the excess sealant that’s squeezed out around the hull fitting and then use white spirit as a lubricant/solvent and lots of rag/paper wipes to get a nice clean edge around the fitting.
The bronze/DZR fittings are in BSP thread sizes and I’ve been using Loctite 5772 to screw on the ball valves and hose tails (but it’s eye wateringly expensive if you have to go out and buy it!) You could get away with putting a smear of Sikaflex on the threads perhaps.
Double clip (clips back to back) hoses onto the hose tails with good quality stainless jubilee clips (Tgere are some poor quality ones in some shops…)

IMHO you should ignore any suggestions anyone makes about having to connect bronze/DZR skin fittings to your anodes with lengths of wire etc. So long as they’re completely independent and not connected metal to metal they’ll be fine. Anodes are for where there are dissimilar metals connected and also in contact with seawater.

My apologies if any of this is teaching grandmothers to suck eggs etc. Just trying to pass on best practice.

Here’s the brine outlet for the watermaker I’m fitting (well above the waterline and hence no seacock) that I fitted yesterday.

 

[Boathook]

I'm use butyl in a cartridge for all my fittings above and below the waterline. As I replace seacocks, etc I'm using trudesign. Not cheap but welll made, etc.