We have a water leak between hosetail and seacock

[nicholat]

We recently installed four Trudesign seacocks and through hulls.

We used Sikaflex 591 for the sealing throughout.

All joints seem watertight as much as we can test out of the water, except on one. We have a leak between the 90 degree hosetail and the top of the seacock. When we poured water down the hose, we had a noticeable leak coming out around the hosetail to seacock join.

Sikaflex was applied to the threads of the hosetail before fitting it into the seacock.

The simplest option seems to be to put plenty of Sikaflex around the join between the hosetail and seacock.

But we can't understand why this one is leaking. Just wondering if anyone else has experienced anything similar and has any words of wisdom on how to fix it?

 

[Poey50]

We recently installed four Trudesign seacocks and through hulls.

We used Sikaflex 591 for the sealing throughout.

All joints seem watertight as much as we can test out of the water, except on one. We have a leak between the 90 degree hosetail and the top of the seacock. When we poured water down the hose, we had a noticeable leak coming out around the hosetail to seacock join.

Sikaflex was applied to the threads of the hosetail before fitting it into the seacock.

The simplest option seems to be to put plenty of Sikaflex around the join between the hosetail and seacock.

But we can't understand why this one is leaking. Just wondering if anyone else has experienced anything similar and has any words of wisdom on how to fix it?

I always found it best to apply goop to both surfaces.

 

[Keith-i]

That seems quite unusual unless there was some kind of damage or burr on the thread that ’wiped’ the sealant off the thread as you screwed it in. Have you tried undoing it? There is an argument not to put sealant on the female part of the thread as it will get pushed down as you tighten the fitting and cause a ridge or partial blockage.

 

[Poey50]

There is an argument not to put sealant on the female part of the thread as it will get pushed down as you tighten the fitting and cause a ridge or partial blockage.

Easily solved by shoving a rag down (or a finger from outside if dealing with the connection of through-hull to ball valve) when it is still wet. A complete ring of excess goop (I used Loctite 5331) is a guarantee that it will seal.

 

[nicholat]

That seems quite unusual unless there was some kind of damage or burr on the thread that ’wiped’ the sealant off the thread as you screwed it in. Have you tried undoing it? There is an argument not to put sealant on the female part of the thread as it will get pushed down as you tighten the fitting and cause a ridge or partial blockage.

We thought it unusual too, especially as the other 3 were done the same way and are ok. We tried to undo it but there is definitely a good mechanical bond.
We'd only put sealant on the hosetail threads, for that reason of it not being pushed down to the ball valve. There was a good amount pushed out around the top.
Perhaps we've just been unlucky with a damaged thread

 

[lustyd]

Being a 90 degree did you maybe turn it a bit while fitting the hose and break the seal? Your method seems fine and is what I did on 7 of them all completely dry. Agree it's possible you got a duff one but they seem really consistent on quality control

 

[bignick]

I had similar when I used Loctite 5331 on my Trudesign seacocks. I hadn’t put nearly enough goop on and most of it had cleaned off. I removed the hosetails and did them aga8n. The clearances on Trudesign fittings seem to be larger than with metal fittings and you need lots of sealant. I found that it worked better to put sealant on the female thread as well, as that isn’t all cleaned off as you screw the fittings together.

 

[dankilb]

I had similar when I used Loctite 5331 on my Trudesign seacocks. I hadn’t put nearly enough goop on and most of it had cleaned off. I removed the hosetails and did them aga8n. The clearances on Trudesign fittings seem to be larger than with metal fittings and you need lots of sealant. I found that it worked better to put sealant on the female thread as well, as that isn’t all cleaned off as you screw the fittings together.

Plus one. Not uncommon from our experience - one leak (with 6 new fittings) with ours and I’d have said I applied ‘plenty’ of thread sealant. BSP isn’t a ‘sealing’ thread, AFAIK, and it seems TD threads are quite greedy for how much they need. One leak - therefore - ain’t bad and I’d be very surprised if it was either a dodgy part or installation.

 

[nicholat]

We managed to get the hosetail off but noticed something that seems odd to us. There is plenty of Sikaflex left stuck around the threads of the hosetail, but none on the seacock threads.

Any ideas why this might be or is it normal for Sikaflex?

 

[Keith-i]

Could there have been some contamination present? Maybe oil or lubricant of some sort. I always clean surfaces/threads with some solvent before using any sealant

 

[bignick]

I also used a wire brush on mine, to remove some of the shinInes, followed by a good wipe with acetone.
since they must be injection moulded, I wondered if the mould was coated with a release agent before the plastic was put in.
The loctite certainly stuck better the second time around.

 

[lustyd]

The sealant here isn’t supposed to stick it’s just to seal, that’s why it’s different to the stuff used for the through hull. You can use Teflon tape for this bit.
Did you tighten until tight or until at right angle? Did you shorten the thread appropriately? A couple of the TD hose tail fittings are too long and nobody seems to know why.

 

[Rappey]

What about using ptfe tape ?

 

[nicholat]

The sealant here isn’t supposed to stick it’s just to seal, that’s why it’s different to the stuff used for the through hull. You can use Teflon tape for this bit.
Did you tighten until tight or until at right angle? Did you shorten the thread appropriately? A couple of the TD hose tail fittings are too long and nobody seems to know why.

We dry fitted to find where the right angle is for the hose connection, which isn't fully tight. We're wondering if we should saw a small amount of length off of the hosetail as we did with the through hull. We'd then be able to get it on tight

 

[Poey50]

Loctite 5331 is less viscous than Sikaflex so easily fills the threads on both sides. It can also be undone if you mess it up. As said earlier coating both male and female threads around the full circumference is foolproof, IMO.

 

[dankilb]

Loctite 5331 is less viscous than Sikaflex so easily fills the threads on both sides. It can also be undone if you mess it up. As said earlier coating both male and female threads around the full circumference is foolproof, IMO.

Plus one. Used it on ours. Nice easy product (handles like a silicone/Sika). Does need more generous application than their instructions suggest (something about applying to a certain proportion of the thread only) - one 38mm valve leaked and needed to reseal with a smear completely around the male thread.

 

[Poey50]

Plus one. Used it on ours. Nice easy product (handles like a silicone/Sika). Does need more generous application than their instructions suggest (something about applying to a certain proportion of the thread only) - one 38mm valve leaked and needed to reseal with a smear completely around the male thread.

Agreed, ignore the instructions and put plenty on both surfaces covering the whole circumference then wipe up the squeeze-out.

 

[B27]

In other areas of plumbing, relying entirely on sealant for a slack parallel thread would be seen as plain wrong.
I can't see that it's good practice on below the waterline seacock plumbing TBH.

Shouldn't parallel thread fittings tighten down onto a sealing washer or something?

A 'fix' that seems to work is to put on a thin nut before the elbow, and tighten that back against the elbow as a lock nut. You still need sealant, but the goo will be compressed between the nut and the elbow and will seal.

 

[dankilb]

Agreed, ignore the instructions and put plenty on both surfaces covering the whole circumference then wipe up the squeeze-out.

Agree that applying to both threads is probably best - assuming the op follows the advice above about not overdoing to avoid excessive squeeze out where you don’t want it

 

[dankilb]

In other areas of plumbing, relying entirely on sealant for a slack parallel thread would be seen as plain wrong.
I can't see that it's good practice on below the waterline seacock plumbing TBH.

Shouldn't parallel thread fittings tighten down onto a sealing washer or something?

A 'fix' that seems to work is to put on a thin nut before the elbow, and tighten that back against the elbow as a lock nut. You still need sealant, but the goo will be compressed between the nut and the elbow and will seal.

The loctite product is specified as a part-adhesive for clocking plastic threaded fittings for this purpose. But also agree there are other ways inc lock nuts and ptfe (the latter just requiring a bit more skill/experience than a sealant from a tube)