Jointing compound for seacocks

I have used Loctite 577 on large course thread metal fittings, I haven't used it on seacocks myself (yet) but that's what I would use.

Hopefully someone will be a long soon with a real seacock example for you.
 
When I asked the (very experienced) installer who replaced a couple of valves on my boat last year why he was still using hemp and paste, he told me that he would have gladly used anything else, if I wouldn't mind either a less durable/reliable installation, or one that would have driven me mad the next time I should have replaced the valve...
 
Imho no, it doesn't. And I'm saying this not only based on what the chap I previously mentioned told me, but also on first hand experience.
 
MapisM said:
Imho no, it doesn't. And I'm saying this not only based on what the chap I previously mentioned told me, but also on first hand experience.
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Been using PTFE tape on threaded joints since it was invented, if put on correctly cannot see a problem , interested to know why not suitable for the marine environment ,
 
I use 577 or 3M 4200, the latter being the same polyurethane sealant as I use on the skin fitting. I realise this means you can never change just the valve but I would never would and never want to. The benefit is that the valve can never rotate on the skin fitting's thread as it can with Ptfe or hemp, and in my books that is an important benefit.
 
dj43 said:
Been using PTFE tape on threaded joints since it was invented, if put on correctly cannot see a problem , interested to know why not suitable for the marine environment,
Click to expand...
I didn't say that it doesn't work well in marine environment. I said that it doesn't work well, period. :D
Reason being that I had some cases where threaded joints sealed with PTFE tape seemed perfect upon installation, but began developing small leaks a few days after.
Something I never experienced with hemp and paste.
Ok, in statistical terms my first hand experience is not that significant, I must admit: it's not like I've done piping jobs every other day, in my life...
Otoh, the chap I previously mentioned did, and also in much bigger boats than mine.
 
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jfm said:
I realise this means you can never change just the valve but I would never would and never want to.
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Why, J? I replaced that couple of smallish valves in my boat just because they were a bit stuck due to lack of usage, but you could have easily thought that the Maestrini bronze skin fittings were brand new, rather than 13 years old. Saying that replacing them would have been overkill is an understatement.
Besides, also accepting that you might prefer to replace both regardless, what would you use to remove the old bits if they are practically welded together, a disc grinder...!? :confused:

Otoh, I see your point on not allowing the valve to rotate, in principle.
But in practice, did you ever come across a valve fitted with hemp or tape which became loose?
In my experience, if there's anything that happens in the bilges, it's some degree of oxidation, which over time "glues" together (so to speak) just about anything.
 
dj43 said:
Been using PTFE tape on threaded joints since it was invented, if put on correctly cannot see a problem , interested to know why not suitable for the marine environment ,
Click to expand...

I believe PTFE is predominantly a thread lubricant and not a specific sealant, however I find it works well on small diameter tapered pipe threads but doesn't work at all well on large diameter parallel threads. The larger diameter threads tend to have more clearance and the PTFE tape doesn't provide a seal.
 
Richard.C said:
I believe PTFE is predominantly a thread lubricant and not a specific sealant, however I find it works well on small diameter tapered pipe threads but doesn't work at all well on large diameter parallel threads. The larger diameter threads tend to have more clearance and the PTFE tape doesn't provide a seal.
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Agreed, what I was questioning was that PTFE did not work well period, I personally am in the camp where I tend to use on the threaded skin fitting the same as I,m using to bed the hull fittings plus the use of back nuts ,as they have all been parallel threads so far ,
 
MapisM said:
Why, J? I replaced that couple of smallish valves in my boat just because they were a bit stuck due to lack of usage, but you could have easily thought that the Maestrini bronze skin fittings were brand new, rather than 13 years old. Saying that replacing them would have been overkill is an understatement.
Besides, also accepting that you might prefer to replace both regardless, what would you use to remove the old bits if they are practically welded together, a disc grinder...!? :confused:

Otoh, I see your point on not allowing the valve to rotate, in principle.
But in practice, did you ever come across a valve fitted with hemp or tape which became loose?
In my experience, if there's anything that happens in the bilges, it's some degree of oxidation, which over time "glues" together (so to speak) just about anything.
Click to expand...

I can heartily recommend a Fein tool being to hand if you are going to remove a skin fitting. That's not a spelling mistake, just the handiest thing you can use doing that job. I have recently replaced 2 sea cocks and skin fittings in the most inaccessible place imaginable, which is of course applicable to every boat. It would not have been possible with a disc grinder which I also have.
They plunge cut through brass to a depth of around 40mm from one side without the need to even move the tool. Best invention ever but not cheap, around £200 for the best mains powered one. Hire one if you can but ssoooo much easier than a grinder. Ct1 for sealing the backnuts and ptfe for the threads. 50 years of plumbing helps..
 
plumbob said:
I can heartily recommend a Fein tool being to hand if you are going to remove a skin fitting. That's not a spelling mistake, just the handiest thing you can use doing that job. I have recently replaced 2 sea cocks and skin fittings in the most inaccessible place imaginable, which is of course applicable to every boat. It would not have been possible with a disc grinder which I also have.
They plunge cut through brass to a depth of around 40mm from one side without the need to even move the tool. Best invention ever but not cheap, around £200 for the best mains powered one. Hire one if you can but ssoooo much easier than a grinder. Ct1 for sealing the backnuts and ptfe for the threads. 50 years of plumbing helps..
Click to expand...

No doubt about it, a Fein is fine.
:encouragement:
 
plumbob said:
I can heartily recommend a Fein tool being to hand if you are going to remove a skin fitting. That's not a spelling mistake, just the handiest thing you can use doing that job. I have recently replaced 2 sea cocks and skin fittings in the most inaccessible place imaginable, which is of course applicable to every boat. It would not have been possible with a disc grinder which I also have.
They plunge cut through brass to a depth of around 40mm from one side without the need to even move the tool. Best invention ever but not cheap, around £200 for the best mains powered one. Hire one if you can but ssoooo much easier than a grinder. Ct1 for sealing the backnuts and ptfe for the threads. 50 years of plumbing helps..
Click to expand...

Can you expand of the use of the Fein tool.
By Fein tool, I think you mean the vibrating tool that cuts a groove.

Like this?????

Fein-4-650x433.png



If so, I have a cheap one (that I bought in Lidls) in my shed in Spain.
But I've only used it to cut wood - works fine for that (excuse the pun)
Are there special bits and how do you set about removing an old skin fitting?
 
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