Re-installing the skin fitting for the sink drain....tips for a first timer

thesaintlyone said:
What is the best sealant, do i need to create a wooden backing plate etc etc
Click to expand...

Sikaflex 291 is the conventional choice, though there are several respectable alternatives. A backing plate in plywood or engineering plastic, or local thickening with GRP, is considered desirable but not essential; lots of production boats don't have them. Mine has some GRP strengthening around the large toilet outlet fitting, but nothing for the others, and I'm comfortable with that.

Plywood, if used, should be coated with resin (or at least decent paint) to stop it soaking up water and rotting.

Pete
 
coopec said:
bow of boat View attachment 57337 stern of boat



IS THAT CORRECT?
Click to expand...

Personally would not fit that type of inlet. As roger says they can get fouled with marine creatures so reducing flow. They are not effective at stopping debris - much better to use an internal strainer, preferably above the waterline and placed immediately above the seacock so that you can rod down if there is an obstruction. Being above the waterline you can take the top off to clean without closing the seacock.

For your non metallic fittings - if you want to use such things suggest you look at the Tru Design range of valves and fittings from New Zealand - sure they will have a distributor in oZ. they are BSP and interchangeable with metal BSP fittings.
 
prv said:
It's often suggested to do the fitting up not quite all the way, allow a few days for the sealant to set, and then do it up fully to compress the now-hard sealant like a rubber gasket. Seems plausible, but note that the professionals rarely or never do this due to the time involved, and I don't think their skin fittings end up leaking.
Click to expand...


Has anyone tried this???
 
thesaintlyone said:
Has anyone tried this???
Click to expand...

Yes - but if you don't hold the skin fitting tightly, you risk having it rotate even slightly and shearing the by now well-cured sealant. Personally I no longer bother and tighten up straight away. I've never yet had a leak. (Of course that statement has now jinxed matters completely).
 
Arcady said:
Yes - but if you don't hold the skin fitting tightly, you risk having it rotate even slightly and shearing the by now well-cured sealant. Personally I no longer bother and tighten up straight away. I've never yet had a leak. (Of course that statement has now jinxed matters completely).
Click to expand...

+1 Never occurred to me that you didn't just insert the hull fitting, slather on sealant and tighten it up...... Job done.
 
Thanks for all the helpful replies, I now need to get a Hose tail fitting to connect between the DZR ball valve and the sink drain hose which should i get as there are plastic/nylon which I presume will not corrode on again or brass

Regards
 
thesaintlyone said:
Thanks for all the helpful replies, I now need to get a Hose tail fitting to connect between the DZR ball valve and the sink drain hose which should i get as there are plastic/nylon which I presume will not corrode on again or brass

Regards
Click to expand...

I dont think it matters. I'd probably fit a DZR one if the valve is DZR.

Puzzled though why , if you are considering plastic for the hose tail why you did not go for a reinforced plastic, such as Marelon or Trudesign, for the whole lot !
 
To be honest vicS it was just simply a question of Cost. The Jouster is going up for sale so I can afford to buy something bigger looking for a stay aboard.
 
The OP never mentioned if this was above of below the WL. HUGE difference. Below the whole bonded backing plate drill makes sense. Above the waterline (at least 6inches) this is a whole lot less serious, and just slapping a mushroom in should be fine.

As for the tighten after cure myth, my understanding is that there is exactly zero evidense that this is better, and plenty of reasons to think that it is worse. Just because it "worked" for a few people...
a. It would have worked the other way too.
b. It has failed for people due to disturbing the seal.

I consider the benefit to be dangerous myth.
 
thesaintlyone said:
Sink drain seacock is below the waterline so i need to make a backing plate what is the best way to do this

Regards ��
Click to expand...

Backing plate ???

You are replacing an old fitting aren't you. What was there originally? I'd have thought the hull thickness ws adequate
 
If there is a feeling that the hull is not thick enough, specifically to take countersunk bolts, the only rational answer is to bond GRP to make a thick, strong spot. HDPE (Starboard) does not bond and wood will rot eventually. It's not hard to do. I like to use a 6mm hole through the center to clamp the layers with a greased bolt, then use that hole to guide the hole saw. In your case, the center hole will be centered with the hole saw in the existing hole.
 
thinwater said:
If there is a feeling that the hull is not thick enough, specifically to take countersunk bolts, the only rational answer is to bond GRP to make a thick, strong spot. HDPE (Starboard) does not bond and wood will rot eventually. It's not hard to do. I like to use a 6mm hole through the center to clamp the layers with a greased bolt, then use that hole to guide the hole saw. In your case, the center hole will be centered with the hole saw in the existing hole.
Click to expand...

Countersunk bolts ???

Surely the op is fitting a standard bronze skin fitting with a domed / mushroom flange on the outside and a back nut inside

Like this
403124_2.jpg
 
You must log in or register to reply here.

Share this page

Top