Orient a valve?

[wooden head]

Pipe threads are tapered not like machine threads that makes it a problem to use a jamb nut. The union is an option Re tapping may work if you don't damage the valve. Personally assuming all metal threads I would use Teflon tape carefully wrapped in correct direction not covering pipe opening at all. Then apply rectorseal #5 pipe dope any real plumbing store will have it it is a plumbers favorite. Rectorseal is a soft set that is over time is dries and thickens. Get it on leave it alone. The layer of Teflon tape is just to build up thickness on thread to seal sooner. Rectorseal will seal and hold position. Excess dope can be wiped off after tightening. Rectorseal is NOT COMPATABLE with some plastics particularly ABS it is approved for use with fuel and gas as well as potable water.

[um saudade]

I have put together a lot of pipe joints and almost never seen the described problem.When a pipe joint is tight enough to have good mechanical strength and no leaks, it can then be tightened further ( up to one complete thread) without damage, allowing for any alignment issues that may be encountered.
This is the same for 1/8 pipe or four inch, though I can tell you that it gets tough to turn three and four inch pipe!It won’t hurt the threads and if the joint is taken apart later, a little pipe dope will allow everything to go back to the same position and seal again.Ifa joint is disassembled and reassembled you may have to go one more thread but this is usually not the case.
Do not back threads off to align fittings, it’s almost a guarantee of leaks to loosen a fitting.
This is art with a little science.
The tighter the joint the less gap between the two sets of threads and the less chance of leakage.The original idea of pipe dope was to lube the thread joint and permit a closer fit without galling.Modern dope both lubes and fills but still the lube function is the primary one.
Both parts of the joint must be held in a wrench or other joints may start moving.The easiest joint to give will turn, thus the properly applied wrenches.If your plumbing “wiggled” as you put it, it simply was not tight enough in the beginning.Pipe is self-supporting for short spans, though for long runs the UMC rules for support should be followed.
What you are calling a 90 degree steel fitting is probably a street elbowIf this just does not work to align the valve handle then remove the street elbow and replace it with an elbow and a close nipple.This will give you two threaded joints that can turn to help in the alignment.
Providing you start with good quality pipe threads, pipe joints have excellent mechanical strength and do not leak. Make sure the threads align at the start and make sure you have at least four complete turns on any pipe joint.That is a bare minimum for that is only about 1/3 of the threads inside the female, a bare minimum.As the valve body may be short, the thread may bottom in the brass valve first and you don’t want to distort the valve so measure first.
No lock nuts on pipe taper if you are looking for a tight joint!

[Terra Nova]

Never...use Teflon tape on a fuel system. Best thread seal is Leak Lock.


Also not a good idea to stack a bunch of fittings.

Instead of blaming, you should be thanking your surveyor for finding a poorly installed fuel system component. Photos would help. But it sounds like you can chase the pipe threads on your tank fitting (not the valve).

[Emmalina]

Why doesn't anybody bring up good old hemp.... It expands when fluid gets to it and unlike teflon you can reverse a bit on your thread. I have given up on most "shiny packaged products " But hemp and paste is getting hard to find nowadays . Maybe its to cheap....

[deblen]

Originally Posted by 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.

One of the No-No's of using plumbers/PTFE/Teflon tape is using too many layers. More than a layer or so leads to incomplete mating of the tapered thread.
Read "Hazards" section of this link

Thread seal tape - Wikipedia, the free encyclopedia

[cabo_sailor]

Dang, I'm constantly amazed at the level and breadth of people's knowledge here. Sure there is some off the wall junk, but this thread is one I read carefully.

Thank you all, I learned something useful.

Rich


Sent from my iPhone using Quantum Entagelment

[Cheechako]

Originally Posted by Emmalina

Why doesn't anybody bring up good old hemp.... It expands when fluid gets to it and unlike teflon you can reverse a bit on your thread. I have given up on most "shiny packaged products " But hemp and paste is getting hard to find nowadays . Maybe its to cheap....

Cause when they put it in the spares kit someone smoked it!

[sy_gilana]

Originally Posted by deblen

One of the No-No's of using plumbers/PTFE/Teflon tape is using too many layers. More than a layer or so leads to incomplete mating of the tapered thread.
Read "Hazards" section of this link

Thread seal tape - Wikipedia, the free encyclopedia

Depends on tape thickness, and if its BSP or NPT, too few layers and alignment is wrong again. Been doing it this way since that stuff came on the market, no problems so far.

[wooden head]

Originally Posted by um saudade

I have put together a lot of pipe joints and almost never seen the described problem.When a pipe joint is tight enough to have good mechanical strength and no leaks, it can then be tightened further ( up to one complete thread) without damage, allowing for any alignment issues that may be encountered.
This is the same for 1/8 pipe or four inch, though I can tell you that it gets tough to turn three and four inch pipe!It won’t hurt the threads and if the joint is taken apart later, a little pipe dope will allow everything to go back to the same position and seal again.Ifa joint is disassembled and reassembled you may have to go one more thread but this is usually not the case.
Do not back threads off to align fittings, it’s almost a guarantee of leaks to loosen a fitting.
This is art with a little science.
The tighter the joint the less gap between the two sets of threads and the less chance of leakage.The original idea of pipe dope was to lube the thread joint and permit a closer fit without galling.Modern dope both lubes and fills but still the lube function is the primary one.
Both parts of the joint must be held in a wrench or other joints may start moving.The easiest joint to give will turn, thus the properly applied wrenches.If your plumbing “wiggled” as you put it, it simply was not tight enough in the beginning.Pipe is self-supporting for short spans, though for long runs the UMC rules for support should be followed.
What you are calling a 90 degree steel fitting is probably a street elbowIf this just does not work to align the valve handle then remove the street elbow and replace it with an elbow and a close nipple.This will give you two threaded joints that can turn to help in the alignment.
Providing you start with good quality pipe threads, pipe joints have excellent mechanical strength and do not leak. Make sure the threads align at the start and make sure you have at least four complete turns on any pipe joint.That is a bare minimum for that is only about 1/3 of the threads inside the female, a bare minimum.As the valve body may be short, the thread may bottom in the brass valve first and you don’t want to distort the valve so measure first.
No lock nuts on pipe taper if you are looking for a tight joint!

Often you cannot tighten enough with brass as the firing may bottom or brass split with the wedge action of tapered nipple. Otherwise I agree with the rest, well written and accurate.

[hpeer]

Thanks for all the help and ideas.

The only thing I'll add to my defense is that when I first assembled this I did pay attention and thought I had it correct. However I had to disassemble and put together again, at which time it felt loose.

In any case we will see. The worse I can do is split the valve and have to buy a new one.

Harbor Freighr had a NPT tap and die set for $15. There stuff usually works for a few tries, at least.

No matter what I do I will probably smear some two part polysulfide over it as I will have it mixed to do another irksome job, belt and suspenders.

[Terra Nova]

Originally Posted by hpeer

...The worse I can do is split the valve and have to buy a new one...No matter what I do I will probably smear some two part polysulfide over it...

Too bad you didn't learn anything from this. Chasing the threaded tank fitting will save you from splitting the valve. Forgetabout polysulphide caulk.

[model 10]

Originally Posted by Terra Nova

Forgetabout polysulphide caulk.

Well you have probably never been on an airliner that didn't have tons of the stuff keeping it from leaking. It works. As above, so below.

[hpeer]

Originally Posted by Terra Nova

Too bad you didn't learn anything from this. Chasing the threaded tank fitting will save you from splitting the valve. Forgetabout polysulphide caulk.

Well ... You have reinforced
1. My observation you severely lack reading comprehension
2. Mu opinion you troll to assert your better than thow opinion of yourself and
3. My determination to ignore you and your ascerbic comments.

It's a pity, I think you are an intelligent guy, it's just that overcompensated inferiority complex.

[captain58sailin]

I've used Teflon tape for years, fuel and hyd. fittings with good results and a few years ago I was told by my local hyd. shop professional that he hated Teflon tape due to poor application tech. by the users. He recommended the Permatex pipe dope and I have been using it ever since with good results. In the last month or so I have taken apart many of the fuel and hyd. fittings on my boat and have found in a good percentage of them the Teflon tape was improperly applied and there were strings of it in between the joint. I am not saying that would happen here, I just prefer the pipe dope these days and it works well. If the orientation is that critical and you have the room to put a union on that might be your best bet to insure a leak free properly tightened joint. Not being there where I could put my hand on the wrench, I would be disinclined to tell you to continue turning the fitting after it is tight. You can get away with a little over tightening, but as has been pointed out before they are a tapered thread and you can either damage the valve or the pipe if you get too serious with it. All the best, I feel your pain.

[Terra Nova]

All the good advice in the world won't help someone sufficiently determined to screw the job up.