Thread Seaiant

[d2dave]

I am doing a repair on my Tvan plumbing. There is a push fitting that screws onto the hot water tank which was leaking at the push fitting end.

I got a new one and fitted it and it leaked at the threaded end. It is female plastic to male brass.

It is in a very tight space. I tried to use teflon tape, but due to the confined space I had trouble trying to wind it on.

What I need is some liquid sealant. Doing some research I found a lot of sealants are suitable for metal to metal or plastic to plastic threads, but not plastic to metal.

Anyone have ideas on what is good to use?

[windsock]

Always had a lot of success with hemp fibre and graphite paste on plumbing joints.

[gromit]

A Google search suggests Loctite 5331 but I have no personal experience.

Colin

[RobMichelle]

The gas water one from Bunnings works, just let it cure before testing.
Can you remove it and put Teflon tape on and refit.
The push end is called John guest fitting, if the hose has a score mark on it it will leak and needs to be pushed in firmly.
The brass end I thought has a rubbery seal on it so when it does up it seals to hws.

[Homestar]

I used Loctite 567 on all joints in the van and motorhome - some between plastic and metal and I've had no problems. I used the 567 because I had a tube of it and it's what we always used to seal fittings when installing block heaters on generators not from any research though so I'm not saying it's designed for it, but it works from my standpoint.

[loanrangie]

What about the old favourite,stag. Seals pretty much anything,gas,fuels, water.

[d2dave]

What about the old favourite,stag. Seals pretty much anything,gas,fuels, water.

I went to my local Reece plumbing supplies to see what their options might be. The bloke behind the counter was very knowledgeable on the subject.

He said that he can sell me a product that would work, but I will never get it off if needed at a later time.

He reckoned that all the products that they have that don't set like concrete, will over time, destroy the plastic.

This got me thinking about some of the products that say "not suitable for plastic", this might be why.

So I settled on Gav's (homestar) recommendation to use Loctite 567. I went to my local Blackwoods store and amongst their sealants was Stag.

I had a look at it but could not get enough information about plastic use.

When looking at the 567 it said on the packet "Not suitable for plastic", so I decided not to use this.

The guy at the counter was very helpful and he went onto his computer and found Loctite 5331.

They did not have it, but I found a store that did. So 5331 it was.

[gromit]

The guy at the counter was very helpful and he went onto his computer and found Loctite 5331.

They did not have it, but I found a store that did. So 5331 it was.

The advantage is that 5331 is listed as suitable for potable water once it's cured for 96 hours at 20 to 23 C (very specific instructions from their data sheet)

Not that 567 would have probably done you any harm......


Colin

[LuckyLes]

Hi d2dave,
What brand is the hot water system? I think you will find that the fittings don't seal on the thread, they seal on a face to face or o'ring type system. As such thread seal or teflon tape won't do the job as it is meant to seal a tapered thread type fitting.
Good luck
LuckyLes

[d2dave]

Les. The fittings have a rubber seal at the bottom of the thread. Same as a fitting that you put on a garden tap.

If that seal leaks the only place the water can escape is through the thread.

I had a new one leak. Due to the confined space it is possible that I did not get it tight enough.

So I wanted to seal the thread as a back up. If you saw the catastrophic damage this small leak caused I want to be sure it doesn't happen again.

[LuckyLes]

That was why I asked what brand od water heater it was. I had a similar situation in my caravan and the only way to fix it was to take out the heater and refit.
Mine was a Truma commonly called a trauma.