Thread Sealing

[Alan Worland 1Participant @alanworland1]

I have been sealing various threaded joints on my steam boat. Cone type joints obviously just nipped up, but others which need to be aligned when tight I have used PTFE tape – folded in half along its length which will then usually be hidden within the joint.

My question is, is this good practice? What might be better?

It works and because the tape acts as a lubricant I feel it should come undone better without seizing?

[Alan Worland 1Participant @alanworland1]

[JasonBModerator @jasonb]

If its to align fittings etc then you can use copper washers, these usually com in a pack of assorted thicknesses. If you know the pitch of the thead its easy to work out approx what thickness you need so when tight the fitting is in the correct position.

 

Eg if you have a 40tpi thread fitting  then one turn is 0.025″ , try it in the bush and if its half a turn out use a 0.013″ washer etc.

 

Jason

[mgjParticipant @mgj]

Cone joints – I really like that orange Loctite Flange Sealant. Easy to apply, anaerobic. Works a treat.

 

On bigger joints and glands, Boss white/tallow and hemp (excellent on stuffing glands for propshafts even full size), or Foliac graphite and hemp (higher temps/steam) takes an awful lot of beating. May be old Victorian technology, but they will seal very big gaps.

 

Dirt cheap too!

Edited By meyrick griffith-jones on 04/01/2010 19:34:11

[NilochParticipant @niloch]

I am totally and indubitably out of my depth here but I recognize Boss White as a plumbing product and have used it as such.  The last time I employed a plumber he said that he had given up using it some time ago in favour of a better product.  I bought my 500g tub of Jet Blue Plus from the Plumb Center which as most of you will know is owned by the American Wolseley outfit.

 

If I may quote a few of the details on the tub:

Suitable for use on gas installation pipework as a classA, Arp and classB thread sealant, as defined by BS EN 751-2:1997

 

WRAS approved for use on cold potable water systems.

 

Working temperature -46C to 260C.

 

Maximum working pressure: 10,000psi (liquids), 2,000psi (gases).

 

Non-toxic.

 

May be used on steel, aluminium, brass, copper, iron, polythene, reinforced fibreglass, PVC and CPVC etc.

 

107 times better than well-chewed gum!!!???!!!???

 

[Alan Worland 1Participant @alanworland1]

Thanks guys, some interesting stuff there!

I take it no one uses PTFE tape then!

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