Stupid pipe threads

GlennAB1 said:
Pay attention to the flow of the forum thread... the elbow fitting with the damaged threads was not pipe
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Not an elbow, an AN816 fitting, flare x NPT, i.e. pipe threads.

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Norman said:
Nope! There's a set of them in my toolbox. And a torque wrench to properly tighten them.
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When the torque is right and the clocking angle ain't what then?

I have a short steel line and a steel "B" nut for each size I normally use, just attach as you would a line and use it as a handle to remove the fitting.
 
3393RP said:
Not a good idea IMHO. Grease makes the gasket and mating surface slick. When the fasteners are tightened, this can cause gasket displacement and leaks.

Better to use a product designed specifically for this application.



http://www.permatex.com/products-2/...sistant-gasket-dressing-flange-sealant-detail
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The item you linked, is what we sometimes call "hylomar" (another version of it in europe). IT CANNOT BE USED IN ROTAX CARBS. If any of it breaks lose, it can clog the metering orifices. Since Rotax carbs are regularly disassembled and reassembled for inspection, the chance of this occurring is greatly increased.

White lithium grease is to be applied in a very thin layer. Basically, it makes it look "wet". It prevents the gaskets from sticking and leaving residue later when removed (thus, leading to leaking).

The design of the carb bowl and other gaskets will not allow slippage. The carb bowl gaskets rest in a recess. The enrichment circuit gasket has screws driven into it and no leg is long enough to really be able to slip. In a larger and more "permanent" gaskets, I use the fuel sealant that you linked, such as in Flight Design CT's fuel tank inspection panels.

White lithium is what is to be used (used to be kleuber, but there are problems with this grease and compatibility with the oil used in rotax, so this is now being shunned). It's more like a thick oil or very runny grease. This is what we were taught to use in Rotax heavy maintenance classes, and I got taught by Eric Tucker himself, who designs the program in cooperation with Rotax's engineers.

Thank you for your feedback :)
 
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GlennAB1 said:
They have a max torque spec. If you can't get it to line up and not leak, get another fitting.
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They are $8.50 each and it takes a week to get here, You buying? do you tell your customer "that will be another week"?
 
Tom-D said:
They are $8.50 each and it takes a week to get here, You buying? do you tell your customer "that will be another week"?
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there are many ways to skin a cat...surprised it would even bother you...
 
Tom-D said:
They are $8.50 each and it takes a week to get here, You buying? do you tell your customer "that will be another week"?
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I have access to bench stock with probably a minimum of 6 at any time, of all the common ones our fleet use. You do what you want with your low budget outfit. Though, it's not your fault if his hardware is worn out
 
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3393RP said:
My favorite is when someone uses silicone sealant on intake manifold valley end gaskets. Blue Permatex silicone seems to be the weapon of choice.

When the manifold is torqued down (and of course before the sealant is cured) the slick elastomer gasket squirts out like a banana peel, leaving a 3/32" void that leaks copious amounts of oil. The gasket on the rear of the manifold is always the one that leaks because you can't see it.

I normally use a tiny bead of 3M 8001 to adhere the valley gasket to the block and let it cure.

Here's a perfect example of globbing on ten times more sealant than needed...this photo was posted on a forum as an example of how to properly seal the intake. :mad2:

Note there is silicone on the manifold and the block! The block gasket mating surface is filthy...yeah, it's gonna leak.

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That's your opinion. I have many track championships with Sprint Cars running at 10K. We NEVER use the cork gasket in the intakes as they spit out or suck in if we are running a vacuum system. We use Permatex "The Right Stuff" and I have never in over 15 years of racing had one issue with using silicone for the intake. I have had new engines straight from Donovan and Garate with the silicone.
 
Tom-D said:
When the torque is right and the clocking angle ain't what then?

I have a short steel line and a steel "B" nut for each size I normally use, just attach as you would a line and use it as a handle to remove the fitting.
Click to expand...

GlennAB1 said:
They have a max torque spec. If you can't get it to line up and not leak, get another fitting.
Click to expand...

Tom-D said:
They are $8.50 each and it takes a week to get here, You buying? do you tell your customer "that will be another week"?
Click to expand...

Clark1961 said:
there are many ways to skin a cat...surprised it would even bother you...
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GlennAB1 said:
I have access to bench stock with probably a minimum of 6 at any time, of all the common ones our fleet use. You do what you want with your low budget outfit. Though, it's not your fault if his hardware is worn out
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Back to the original premise of this thread- yes, pipe threads are stupid in this application and this thread proves it.

BTW, what the hell do you guys have against cats??! Why would anyone know even one way to skin one??
 
Is this OK for fuel and oil fittings?
I'll rephrase the question: What is this suitable for?:D
 

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GlennAB1 said:
Though, it's not your fault if his hardware is worn out
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The only time I'd replace a pipe threaded fitting is when the customer forgets to keep them when they return the core, or they mess up the threads.
 
Sleepingsquirrel said:
Is this OK for fuel and oil fittings?
I'll rephrase the question: What is this suitable for?:D
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That stuff is full hardening, and not 100LL soluble, if you expect to ever remove the fitting don't use it.
 
Tom-D said:
That stuff is full hardening, and not 100LL soluble, if you expect to ever remove the fitting don't use it.
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Thanks! I've used it without thinking with good results. This THREAD has been a learning experience for me. :D
 
EZ-Turn is good stuff with a million uses. It's like Brylcreem, a little dab will do ya. Buy a tube and it'll probably last you a lifetime.

What I've noticed with just about everything (RTV being a particularly prominent example) is that people use WAY too much. Even cream filled donuts are not so bad so long as you don't eat a whole box of them.
 
3393RP said:
My favorite is when someone uses silicone sealant on intake manifold valley end gaskets. Blue Permatex silicone seems to be the weapon of choice.

When the manifold is torqued down (and of course before the sealant is cured) the slick elastomer gasket squirts out like a banana peel, leaving a 3/32" void that leaks copious amounts of oil. The gasket on the rear of the manifold is always the one that leaks because you can't see it.

I normally use a tiny bead of 3M 8001 to adhere the valley gasket to the block and let it cure.

Here's a perfect example of globbing on ten times more sealant than needed...this photo was posted on a forum as an example of how to properly seal the intake. :mad2:

Note there is silicone on the manifold and the block! The block gasket mating surface is filthy...yeah, it's gonna leak.

DSCN9187.jpg
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Thing is that GM has been using RTV in that area since the early 80's with no troubles. But, what you have pictured is way in excess, and an invite for trouble.
 
Re the original post and pipe the threads...

On the RV 10, I found that the pipe thread fittings in the fuel system don't require any thing. No lube if done with care, no leaks because it's a relatively low pressure app. And of course nothing on the flare fittings, just good flares.

For oil and brake systems I tried a number of things to stop several leaks. The brake system leaks seem to stem from clocking issues. Both seem to result from high pressure. One thing that has worked perfectly is this Permatex Producr. I've also successfully used it on some non aviation high pressure pipe fittings.
http://www.permatex.com/products-2/...rmatex-high-performance-thread-sealant-detail

It doesn't harden and always reversible. Seems to make up the difference for under torquing.
 
BiffJ said:
They can also have straight pipe threads vs tapered pipe threads......
at least we don't have whitworth and BSP to deal with....normally.

Frank
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Straight pipe thread is BSP. Many yachts, especially Asian built yachts, are a mish mash of SAE, Metric, BSx, and Whitworth bits. It's always fun times when they screw NPT fittings into BSP threads and then try to make it not leak.
 
Tom-D said:
When the torque is right and the clocking angle ain't what then?

I have a short steel line and a steel "B" nut for each size I normally use, just attach as you would a line and use it as a handle to remove the fitting.
Click to expand...

Use a tap and run it in the extra clocking angle you need to make alignment.
 
Henning said:
No, DON'T use thread tape on an airplane.
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I spoke with one of the instrument repair stations (the ones that actually open up and overhaul instruments), we are supposed to use thread tape on the instrument fitting threads, skipping the first 2-3 threads. They will void any instrument warranties if they find any goop being used as sealant. Basically, any pneumatics are to use thread tape, any fluid liquid lines uses "goops" as appropriate.

The reasoning for the thread TAPE and not goop, is that the tape will get caught in the inlet filter, whereas goops can go right through and into the bearings.
 
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Anticept said:
I spoke with one of the instrument repair stations (the ones that actually open up and overhaul instruments), we are supposed to use thread tape on the instrument fitting threads, skipping the first 2-3 threads. They will void any instrument warranties if they find any goop being used as sealant. Basically, any pneumatics are to use thread tape, any fluid lines uses "goops" as appropriate.

The reasoning for the thread TAPE and not goop, is that the tape will get caught in the inlet filter, whereas goops can go right through and into the bearings.
Click to expand...

I have never seen those fittings require anything but light lubrication to go in and seal perfectly, we're talking a couple of inches of high volume vacuum, not 60psi of oil.
 
Anticept said:
I spoke with one of the instrument repair stations (the ones that actually open up and overhaul instruments), we are supposed to use thread tape on the instrument fitting threads, skipping the first 2-3 threads. They will void any instrument warranties if they find any goop being used as sealant. Basically, any pneumatics are to use thread tape, any fluid lines uses "goops" as appropriate.

The reasoning for the thread TAPE and not goop, is that the tape will get caught in the inlet filter, whereas goops can go right through and into the bearings.
Click to expand...

Repair stations have no authority to set policy, all they can tell you is what they do.

There isn't enough vac pressure this side of the moon to draw EZ turn into a gyro.
 
Anticept said:
I spoke with one of the instrument repair stations (the ones that actually open up and overhaul instruments), we are supposed to use thread tape on the instrument fitting threads, skipping the first 2-3 threads. They will void any instrument warranties if they find any goop being used as sealant. Basically, any pneumatics are to use thread tape, any fluid lines uses "goops" as appropriate.

The reasoning for the thread TAPE and not goop, is that the tape will get caught in the inlet filter, whereas goops can go right through and into the bearings.
Click to expand...
Pneumatics are fluids. ;) When I was in the Air Force in the late '70's, it was Avionics standard practice to use thread tape on all pitot static fittings at instruments. Yeah, I know, we're talking about vacuum system instruments. F-4 and T-38 didn't have those.
 
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Tom-D said:
Repair stations have no authority to set policy, all they can tell you is what they do.

There isn't enough vac pressure this side of the moon to draw EZ turn into a gyro.
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They do set warranty policy. I agree, there isn't enough vac pressure, but I'm following their install instructions for the aforementioned reason.

GlennAB1 said:
Pneumatics are fluids. ;) When I was in the Air Force in the late '70's, it was Avionics standard practice to use thread tape on all pitot static fittings at instruments. Yeah, I know, we're talking about vacuum system instruments. F-4 and T-38 didn't have those.
Click to expand...

In fluid dynamics, gas and liquids are both fluids, but in common industry terminology, fluid is synonymous with liquid, the phase state. :)
 
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