Orient a valve?

[hpeer]

I need a valve on a fitting. It MUST be in a certain orientation. I can not replace the fitting, welded in. Diesel pick up line.

Is there some pip dope that will firmly hold this in place?

It was working until the surveyor yanked on it!

[Wotname]

Let me make some assumptions first.
Valve and fitting both metal?
Valve screws onto fitting and can rotate 360 degress during assembley?
Valve can be tightened up snug and when it is, it doesn't leak but the outlet is facing in the wrong direction for rest of piping?

If all the above is true, then some type of sealant (pipe dope) must have been used in the past but clearly one that was not surveyor proof (). Is there any way of finding out what the PO used?

The best product to use may be dependant on the number of degrees between of turning between the required position and the fully tightened position i.e. how far do you have to back it off from fully tight. I can't tell from your description if this small (say 10 to 30 degrees) or medium (say 90 to 180 degrees) or large (say + 270 degrees or even many turns).

If small, a liquid gasket solution should suffice or a thread sealing paste and if medium, then maybe a two part polysulfide sealant that is used on flexible fuel tanks.

However if the discrepancy is large, then a more mechanical solution may be in order. Can you run another nut down the fitting first and lock the valve against it. The nut would most likely have to be cut down in thickness and pipe dope still be used. Even metal set epoxy might help.

But it really depends on the size of the discrepancy and to a lesser extent, the diameter of the fitting.
Tell us these things and we may come up with a specific product that is suitable.

[Cheechako]

Yes there is.

[hpeer]

Thanks for the reply.

Your assumptions are correct.

It the top of my fuel tank, tank is integral to the steel hull. The fittings are welded to the removable tank top inspection port.

Because the tank is under the sole, ther is little room between the tank top and the sole bottom.

The pick up fitting is welded to the inspection plate, then a 90° steel fitting, then a brass ball valve. The valve must be vertical to have the right orientation to turn the lever.

I actually built this contraption, without going into details the whole thing, including vent fittings, must be assembled in a specific order. It all works just fine, as intended. I had it all sealed up with Boat Life polysulfide but the surveyor wants something "tight". "No wiggle."

I had intended to seal the whole thing with a fuel tank 2 part polysulfide, but it didn't get done. My helper coated the underside of the inspection plate not the fittings on the top side. I love her anyway, and she was trying her best.

I've bought a bit more of the two part polysulfide and, if pressed will use that. I have every confidence it would work. I'm not so sure the surveyors will like it.

The second nut is a good idea, except these are plumbing threads, and are intended to seal as the tighten, no? So I fear the nut would hold the valve off too far. Not sure I can even get a nut for this thread.

The valve starts to tighten just as it passes the correct orientation. It's good and tight 180° out.

Thanks for the help.

[hpeer]

Originally Posted by Cheechako

Yes there is.

OK tease.....what is it?

[hellosailor]

Perhaps there was some type of Teflon tape used on the threads. That would be fuel-proof but when snugged up, the orientation would depend on how much tape there was.


A true machinist could "regulate" the valve position the same way that gunsmiths "regulate" the screws in fine firearms. They gradually polish off the end of a screw, so the thread now begins at a slightly different orientation, and when the screw is properly tightened down, the head (slotted) all align in the proper direction.


I'd think judicious use of a sanding wheel, grinder, or plain bastard file, could take the thread back 180 degrees on one piece or the other. Just aim for something less, and then work your way down to 1/2 revolution in small bites. And of course, clean out the metal bits.


Teflon tape is easier, but you can't be as proud of the invisible perfection.(G)

[deblen]

Pick up a brass ground union, brass close nipple & a small bottle of Teflon Pipe Thread Sealer (dope)
Screw half of ground union on existing tank nipple.
Use teflon pipe dope,not tape. Fuel degrades tape.
Assemble the other half of ground union to existing shutoff valve using close nipple & T dope.
Orient the valve wherever you like & tighten the ground union halves together.
Do not use any t dope or any other goop on ground union mating surfaces-they are machine fit.
Put remaining teflon dope in tool kit & dispose of all teflon tape-it causes all sorts of problems when pieces of tape shred off & float thru systems.

Cheers/ Len

[Wotname]

Originally Posted by hpeer

Thanks for the reply.

Your assumptions are correct.

It the top of my fuel tank, tank is integral to the steel hull. The fittings are welded to the removable tank top inspection port.

Because the tank is under the sole, ther is little room between the tank top and the sole bottom.

The pick up fitting is welded to the inspection plate, then a 90° steel fitting, then a brass ball valve. The valve must be vertical to have the right orientation to turn the lever.

I actually built this contraption, without going into details the whole thing, including vent fittings, must be assembled in a specific order. It all works just fine, as intended. I had it all sealed up with Boat Life polysulfide but the surveyor wants something "tight". "No wiggle."

I had intended to seal the whole thing with a fuel tank 2 part polysulfide, but it didn't get done. My helper coated the underside of the inspection plate not the fittings on the top side. I love her anyway, and she was trying her best.

I've bought a bit more of the two part polysulfide and, if pressed will use that. I have every confidence it would work. I'm not so sure the surveyors will like it.

The second nut is a good idea, except these are plumbing threads, and are intended to seal as the tighten, no? So I fear the nut would hold the valve off too far. Not sure I can even get a nut for this thread.

The valve starts to tighten just as it passes the correct orientation. It's good and tight 180° out.

Thanks for the help.

Well if you made in the first place, then all you have to do is remake it again but this time get it right

Seriously though, clearly you can make stuff so that is a good starting point.

You need a half a pitch more on the valve thread and all would be good. And yes, the two part polysulfide would be enough to hold it - except for the surveyor and you can't really blame him - proper tight is best after all!

Get another valve and try it, the thread lead in might just be different.

If not then following is tedious but would work I reckon.

Cut the end off the threaded section off the new valve, say about 3 pitches long - let's call it a "slim nut"! Run that onto the fitting until it is tight, then run your real valve onto the fitting until it is mates with the "slim nut", see where you handle is and then file back the valve until it has the handle in the correct position. Worst case will be filling back almost one pitch! Sort of what hellosailor described!

Reassemble with sealant everywhere and it will feel tight for the surveyor and be fuel tight for you.

If you are real pedantic, when you get everything dry assembled with "slim nut" tight and valve nicely butted up against it and handle correctly oriented, then mark the "slim nut" and valve with a fine line on say two hex faces, remove everything, refit on a spare fitting (but not tightly), line up the marks and braze the "slim nut" to the valve hex, dress the brazing, remove from spare fitting and voila, you should have a valve that will tighten in exactly the right spot. Still use some sealant!

If that's too much work, get another surveyor

[hpeer]

I like the last line a LOT!

Soooo, I was Googling "ground union" and came across a NPT tap and die set! $15 at Harnor Freight.

Hmmmm?

Just run a tad more thread?

[deblen]

Originally Posted by hpeer

I like the last line a LOT!

Soooo, I was Googling "ground union" and came across a NPT tap and die set! $15 at Harnor Freight.

Hmmmm?

Just run a tad more thread?

You will need a lot of patience to get it just right by re-threading IMHO
Use the ground union-your situation is one of the purposes of ground unions.
The other main purpose is to allow you to disassemble/assemble plumbing easily & quickly. Use lots of them in plumbing.

Buy the tap & die set also-they are handy for cleaning up damaged threads as well as making new ones.I suspect it may be for nuts & bolts,& may not necessarily contain NPT taps & dies. Thread pitch gauges usually come in these kits & are very handy. Cheers/Len

[Cheechako]

Originally Posted by hpeer

OK tease.....what is it?

I was teasing your tease. What is the valve? :>)

[hellosailor]

"Teflon, Viton, and Nylon have very little reaction to biodiesel and are among the materials that can be used to update incompatible equipment. " From the National Biodiesel Board's web site.


Very little eats Teflon.


On the other hand, IMPROPERLY applying Teflon tape is easy, and that produces snippets of Teflon that will go downstream and clog injectors and other tight fittings--so it should only be used upstream of filters, which eliminate that problem even if the Teflon is applied incorrectly. It must be wrapped in the right direction, and not allowed to stretch over the top of the fitting, in order to prevent the threads from being shredded off. Also, cleaned off and replaced whenever the threading is opened again.


No different (no more obvious) than folks who re-use copper crush washers without any idea of why that just shouldn't ever be done.

[deblen]

Originally Posted by hellosailor

"Teflon, Viton, and Nylon have very little reaction to biodiesel and are among the materials that can be used to update incompatible equipment. " From the National Biodiesel Board's web site.


Very little eats Teflon.


On the other hand, IMPROPERLY applying Teflon tape is easy, and that produces snippets of Teflon that will go downstream and clog injectors and other tight fittings--so it should only be used upstream of filters, which eliminate that problem even if the Teflon is applied incorrectly. It must be wrapped in the right direction, and not allowed to stretch over the top of the fitting, in order to prevent the threads from being shredded off. Also, cleaned off and replaced whenever the threading is opened again.


No different (no more obvious) than folks who re-use copper crush washers without any idea of why that just shouldn't ever be done.

OK.
Agree-inexperienced/untrained users often apply Teflon tape incorrectly.
Personal opinion-it's safer & easier to use Teflon pipe dope. / Len

[deblen]

Originally Posted by deblen

OK.
Agree-inexperienced/untrained users often apply Teflon tape incorrectly.
Personal opinion-it's safer & easier to use Teflon pipe dope. / Len

I've been using this Permatex version successfully for many yrs.

Thread Sealants : Permatex® Thread Sealant with PTFE

[sy_gilana]

Put the valve on without any sealant. Tighten to tight, then reverse to the correct orientation. Now unscrew and count the turns carefully. Put on Teflon Tape, about 13 turns, tapering it and going clockwise without any overlap of the hole, start at the back end layering it toward the hole end. Put on the valve and count the turns again. If it does not tighten before the same turns, take off and put on more tape.