My big nut..

[Davy]

On the milk filter for the parlour, there is a 6"nut tightening against the housing. There is play in the threads now, and sometimes it'll leak milk if care isn't taken when tightening. Is there anything can be done with the thread? Something like plumbers tape, but more permanent.

 

[Servac]

The sealing should be done by the o ring not the thread. Does it not tighten properly any more?

You could buy a new nut and thread and get someone to weld it on with a tig welder.

 

[Dukes Fit]

Is it on and off regularly or done up and left?

Try Swak pipe thread sealant. It’s made by Swagelok. Used to use it on 3” stainless hydraulic fittings to seal and prevent galling and while pressure testing up to 60k psi and didn’t have any problems with it.

 

[Davy]

The sealing should be done by the o ring not the thread. Does it not tighten properly any more?

You could buy a new nut and thread and get someone to weld it on with a tig welder.

It'll slip on the thread and not tighten enough sometimes

 

[Davy]

Is it on and off regularly or done up and left?

Try Swak pipe thread sealant. It’s made by Swagelok. Used to use it on 3” stainless hydraulic fittings to seal and prevent galling and while pressure testing up to 60k psi and didn’t have any problems with it.

Opened once before and once after milking. Left done up in between

 

[Dukes Fit]

Sounds like your thread is worn, any liquid sealer wouldn't work as its designed to be applied then left
Best option could be to cut back 6 inches and have a new thread and short section of tubing tig welded on

 

[Servac]

RJT Union - Berkeley Stainless Fittings Limited

The RJT (Ring Joint Type) union is by far the most popular in the UK. Complete with 304 Stainless Steel Nut, and 316 stainless steel male and liner.

www.berkeleystainless.co.uk