Stupid pipe threads

i posted on the corvette forum where someone was asking about using RTV on a differential, I said that only bubba lets RTV near his corvette. boy did I get flamed for that.

bob
 
ollopa said:
N62DN
Sounds a little different than the way some of you guys are imagining it. Stupid slathered on top of incompetent. It's especially awesome how he ignored advice from others and just slathered more RTV all over his joints.
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This seems to be the case (minus the insults hurled at a fellow RV10 builder).
bnt83 said:
In this case its alleged that pipe dope (in this case RTV was used) plugged the fuel flow sensor which doesn't contain a bypass, not a fuel quantity problem.


They also accuse Vans assembly instructions to be inadequate, not covering NPT assembly.

Lawyers are blaming everyone except the RTV manufacturer.
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I never heard of RTV being referred to as any kind of 'pipe dope'

I assume that this case will never see a courtroom let alone a jury. Payments will be made and no fault found.
 
3393RP said:
Most products at the auto parts stores labeled "RTV" are the silicone type that cure in a reaction with moisture in the air. These sealants are for use in gasket applications and other similar situations, not for pipe joint compounds.

Pipe "sealants" (which is more properly called pipe joint compound) usually contains PTFE and kaolin, clay, vegetable oil, rosin, and other binders. However, there are compounds made specifically for use with fuel and it is without a doubt essential to use the proper compound for the fluid in use.

Tapered pipe threads are made leakproof via a physical mechanism. Tightening the joint reduces the clearance between the threads. The addition of pipe joint compound isn't made to stop leaks.

It is actually a lubricant which reduces the friction between the pipe and the fitting (or the friction between a fitting and a threaded opening in a casting such as an engine block). The pipe joint compound also fills any minute voids between the threads and helps seal the joint, but most of the sealing effect is from the interference fit of the two pieces.

Applying more "sealant" on a joint has little effect in making it less likely to leak. The integrity of the joint is more dependent on properly formed threads.

Many people daub copious amounts of joint compound on a leaky joint in the misguided belief it will stop a leak. Most of the time this is a vain effort because misformed threads are the problem.

In this particular case, it sounds like the assembler did just as I have described, to the point where excess joint compound clogged the pipe and impeded the flow of fuel.

If a the threads on a joint are properly formed, it takes very little joint compound to effect a proper leakproof seal. The amount is certainly less than any amount which flows out of the joint and would need to be wiped off.

Keep this in mind when you are assembling such a system. Make sure the joint compound is specified for use with gasoline, such as Permatex 51H. PTFE tape should not be used for gasoline systems because it can shred and cause blockages.

http://www.permatex.com/documents/TDS/automotive/80045.pdf
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Great article on pipe threads here that appeared in EAA Experimenter magazine. (It contradicts at least one point above but that's not to say which is correct.)

Make Sure the Pipe Fits
 
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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But not before it's sold...
 
bnt83 said:
Even fuel lube can cause a problem.
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Actually, Van's cautions against using Fuel Lube as a joint compound on NPT threads. Their first recommendation is Permatex #2 or #3. They say that some builders have had success using certain anaerobic Pipe dope compounds. But, nowhere do they mention using silicone RTV on NPT threads. Perhaps, it was considered so basically wrong, they didn't feel the need to.

If I recall, Tony Bingelis covered this in one of his books, didn't he?
 
Parker fuel lube:
http://www.aircraftspruce.com/catalog/cspages/ezturnlube.php?clickkey=9406

Is a lubricant that allows you to over tighten a pipe thread to align the clocking angle with out galling the aluminum fittings, It's primary purpose is to lubricate Parker "O" rings.

It is understandable the RV objection to the use of it as a thread lubricant.

But it's better than the RTV usage.
 
I use this on all of my RV-10 pipe threads. I have used it for years in the HVAC/Refrigeration industry...

http://www.highsidechem.com/leaklock.html

After reading many posts from THREE different forums, most are focused on that dang blob of RTV or the lawsuit. How about going out and practicing your slow flight, stalls(without reference to airspeed), emergency engine out procedures. Doug Nebert and his 4 year old step granddaughter might still be with us today if he had focused on flying that RV-10 to a safe landing spot instead of trying to extend his glide across the river to an airport less than one mile away. We never know when our engines will stop producing power and we need to be prepared at all times.

Our RV-10 will only haul my wife and two children from here on out.
 
Just to show what NTSB found...

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I thought this was interesting too--apparently there was a carseat involved:
All occupants appeared to have both their lap and shoulder belts secured during the accident
sequence. The child’s seat was a Graco booster seat, model 1781044 (serial number 0784129).
According to the manufacture, the seat is designed to sustain g- loading as specified in Federal Safety
Standard 213. This includes a space envelope of 32 inches for the head and 36 inches for the knees.
The seat’s manual specifically prohibits usages in aircraft, which at states is due to the limitation of
no shoulder harnesses available.
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Tom-D said:
Parker fuel lube:
http://www.aircraftspruce.com/catalog/cspages/ezturnlube.php?clickkey=9406

Is a lubricant that allows you to over tighten a pipe thread to align the clocking angle with out galling the aluminum fittings, It's primary purpose is to lubricate Parker "O" rings.

It is understandable the RV objection to the use of it as a thread lubricant.
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Its primary purpose is to lubricate plug-type fuel valves.

From:http://www.skygeek.com/united-ez-turn-fuelube.html

United Erie EZ-Turn Fuel Resistant Lubricant

EZ Turn is a revolutionary sealant and lubricant for oil and fuel line valves. Resistant to high temperatures, it is especially effective where high octane fuels and aromatics are present.The functional equivalent of fuel lube, EZ Turn will not gum, dry out, or crack. You can rest assured knowing that each shipment is independently tested.
EZ Turn is very efficient as a gasket paste and anti-seize agent and is excellent for tapered plug valves, marine applications, and aircraft engine manufacturing.
Approvals/References/Specs

SAE Specification: AMS-G-6032
US Military Specification: MIL-G-6032 Type 1
US Military Specification: MIL-G-6032D Ammend 1 Type 1





The Mil-Spec:


MIL-G-6032D (NOTICE 1), MILITARY SPECIFICATION: GREASE, PLUG VALVE, GASOLINE AND OIL RESISTANT, NATO CODE NUMBER G-363, METRIC (10 SEP 1999) [S/S BY SAE-AMS-G-6032]., MIL-G-6032D, dated 29 June 1984, with Amendment 1, dated 8 April 1988, is hereby canceled. Future acquisition for this item should refer to SAE-AMS-G-6032, "Grease, Plug Valve, Gasoline and Oil Resistant, NATO Code Number G-363, Metric."


Parker O-ring lube is entirely different.

http://www.parker.com/portal/site/P...0227&vgnextcat=O-RING+LUBRICANTS&vgnextfmt=EN
 
To add, Never use any material that solidifies on any fuel or oil system.
 
That fuel pump/transducer mashup is something else. The pump is an auto parts store cheapo special, and the fuel line and fittings look like they came from a coffee can on a workbench.

I wouldn't install a $16.99 fuel pump on my aircraft.

http://m.ebay.com/itm/271771462572
 
3393RP said:
That fuel pump/transducer mashup is something else. The pump is an auto parts store cheapo special, and the fuel line and fittings look like they came from a coffee can on a workbench.

I wouldn't install a $16.99 fuel pump on my aircraft.

http://m.ebay.com/itm/271771462572
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Yeah, automotive electric pump failures leave cars stranded alongside the road every day.

Seriously, why do you think the $200 one with aviation paperwork is better?
 
kyleb said:
Yeah, automotive electric pump failures leave cars stranded alongside the road every day.

Seriously, why do you think the $200 one with aviation paperwork is better?
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Maybe because a $16 (after overseas shipping and several middlemen markup) Chinese no-name aftermarket universal fuel pump is sub-Walmart grade.

Seriously, there are good automotive pumps. This likely ain't gonna be one of them.

The generic aftermarket automotive crap typically doesn't last a year.
 
Certified plane, certified mechanic, certified oil cooler. I would guess the channel locks that did this to the certified AN pipe fitting were not certified.
elbow.jpg
 
And yes that is teflon tapes on the thread.
 
yetti said:
And yes that is teflon tapes on the thread.
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TEFLON tape itself is not bad as long as it is used properly. That said, most folks aren't trained how to use it properly. My A&P has used TEFLON tape on my aircraft's fuel system and I have absolutely no qualms about it. He and I did discuss the application prior to the work.
 
Tom-D said:
Parker fuel lube:
http://www.aircraftspruce.com/catalog/cspages/ezturnlube.php?clickkey=9406

Is a lubricant that allows you to over tighten a pipe thread to align the clocking angle with out galling the aluminum fittings, It's primary purpose is to lubricate Parker "O" rings.

It is understandable the RV objection to the use of it as a thread lubricant.

But it's better than the RTV usage.
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Dan Thomas said:
Its primary purpose is to lubricate plug-type fuel valves.

From:http://www.skygeek.com/united-ez-turn-fuelube.html

United Erie EZ-Turn Fuel Resistant Lubricant

EZ Turn is a revolutionary sealant and lubricant for oil and fuel line valves. Resistant to high temperatures, it is especially effective where high octane fuels and aromatics are present.The functional equivalent of fuel lube, EZ Turn will not gum, dry out, or crack. You can rest assured knowing that each shipment is independently tested.
EZ Turn is very efficient as a gasket paste and anti-seize agent and is excellent for tapered plug valves, marine applications, and aircraft engine manufacturing.
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Actually, I found the best use for EZ Turn fuel lube was put a dab on a finger to hold washers and nuts that need to be installed in awkward locations.

I also used it on the O-ring on my fuel cap. It gets a bit gummy and stiff with exposure to fuel but it persists and doesn't create fuel system clogging debris.

My pipe thread fuel system fittings were installed dry; none leaked.

I used Permatex's high pressure/high temp sealant on my oil system and hydraulic pipe threads. Without it, they leaked.

I still have 2 almost full tubes of it so the search continues.
 
Bill Watson said:
Actually, I found the best use for EZ Turn fuel lube was put a dab on a finger to hold washers and nuts that need to be installed in awkward locations.

I also used it on the O-ring on my fuel cap. It gets a bit gummy and stiff with exposure to fuel but it persists and doesn't create fuel system clogging debris.
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On the fuel cap, it works better if a little is tucked between the metal cap surface and the rubber gasket. That lets the cap turn on the gasket easily insted of the gasket turning on the filler neck, and doesn't attract dust.

And yes, it's handy for sticking stuff to a finger or a screwdriver blade to sneak a washer or nut or whatever into some impossible spot. I saw an ad for a small jar of goop "designed" for that purpose; I bet it was just repackaged Fuel Lube, marked way up.
 
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Clark1961 said:
TEFLON tape itself is not bad as long as it is used properly. That said, most folks aren't trained how to use it properly. My A&P has used TEFLON tape on my aircraft's fuel system and I have absolutely no qualms about it. He and I did discuss the application prior to the work.
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Teflon tape can actually extrude forward into the fuel or oil line as the fitting wedges in there and the tape shreds. And when the fitting is removed, lots of bits of shredded tape is left behind and gets flushed into the system once it's reassembled and will cause major grief. That's why no engine or airfrrame manufacturer will tolerate its use in their systems.
 
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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Been there and done that... Makes for interesting times when you try to pry the manifold back off.

A bead of RTV the right size is still better than the crappy cork ones, though:
81408.jpg



They slip out of place, shrink over time, and leak all over. Guaranteed to be the one in the rear that you need a mirror to inspect :p

I really like the steel-core silicone end seals and valve cover gaskets that go on dry. They seal up well, resist crushing, stay in place, and are removable. I'll put just a tiny dab of RTV on the corners... More is not better.
 
Three years ago I sold my 60's v-drive flatbottom boat, it had a '64 Ford 427 in it. I used the OEM cork gaskets on the oil pan, the intake manifold ends and the valve covers.

I fixed the gaskets in place with a small bead of 3M 8001 "gorilla snot" RTV on one side of the gasket and let it dry. In the case of the oil pan and valve covers, I used the RTV on the sheet metal part, and glued the manifold gasket on the block.

In the fourteen years I owned the boat, the gaskets never leaked. I even removed the valve covers every season the adjust the valves.

If the pan and cover flanges are properly straightened and the parts are torqued correctly cork gaskets work just fine. I've never had problems with them leaking.
 
kyleb said:
Yeah, automotive electric pump failures leave cars stranded alongside the road every day.

Seriously, why do you think the $200 one with aviation paperwork is better?
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The old standby Holley red (7 psi) or black (14 psi) pumps are less than $200 and they are rotary vane pumps instead of the synthetic rubber diaphragm that the $16.99 pump has.

If you want to spend more money there are plenty of choices, up to the $550 Aeromotive 1000.

Installing that $16.99 special in an aircraft is crazy.
 
ollopa said:
Down at the pick 'n pull, RTV is the hallmark of an amateur repair.
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This is the part of this discussion that is missing. The category is called- Experimental Amateur Built. This is what happens when you allow ordinary amateur people build airplanes, or really build anything. Some take the task very seriously and educate themselves as to how and why the pros do it the way they do it and others just don't and do it their own way.

In the E/AB community there seems to be an attitude among many that the way certified planes are built and maintained is just inflated, government regulated horse pucky. Many being of above average intelligence figure out ways to do the same thing as the certified planes, only cheaper and save a load of money. Hence the $16.99 fuel pump.

This attitude extends to the procedures as well. People seem to have a lot invested in stories of wise old timers and their unorthodox bag of tricks rather than what is in AC 43.13. "Well you know when we had this problem on the farm, we always just used a bunch of RTV on those joints and it worked every time! Hell, these are nothing but glorified tractor engines, right?"

Likely he may have done repairs to the household plumbing and in that case, using lots of thread compound usually makes it leak tight first try. Not much different between a water pipe and a fuel line, right? The same idea, right?

The crux I think, of this lawsuit is, Vans was not specific enough on the assembly of the fuel system. The manual seems to be written for thinking hobbyists that want to learn, not know it all shade tree amateurs. Vans hope seems to be, that the builder would do some homework and come to the correct conclusion on their own.

Why Vans wants to be so vague about this process when they know a certain amount of dumbasses will be building this thing, is beyond me. No doubt the doing of their legal department. They will find out how well their counsel is. I guess so far it's been pretty good.
 
Dav8or said:
This is the part of this discussion that is missing. The category is called- Experimental Amateur Built. This is what happens when you allow ordinary amateur people build airplanes, or really build anything. Some take the task very seriously and educate themselves as to how and why the pros do it the way they do it and others just don't and do it their own way.

In the E/AB community there seems to be an attitude among many that the way certified planes are built and maintained is just inflated, government regulated horse pucky. Many being of above average intelligence figure out ways to do the same thing as the certified planes, only cheaper and save a load of money. Hence the $16.99 fuel pump.

This attitude extends to the procedures as well. People seem to have a lot invested in stories of wise old timers and their unorthodox bag of tricks rather than what is in AC 43.13. "Well you know when we had this problem on the farm, we always just used a bunch of RTV on those joints and it worked every time! Hell, these are nothing but glorified tractor engines, right?"

Likely he may have done repairs to the household plumbing and in that case, using lots of thread compound usually makes it leak tight first try. Not much different between a water pipe and a fuel line, right? The same idea, right?

The crux I think, of this lawsuit is, Vans was not specific enough on the assembly of the fuel system. The manual seems to be written for thinking hobbyists that want to learn, not know it all shade tree amateurs. Vans hope seems to be, that the builder would do some homework and come to the correct conclusion on their own.

Why Vans wants to be so vague about this process when they know a certain amount of dumbasses will be building this thing, is beyond me. No doubt the doing of their legal department. They will find out how well their counsel is. I guess so far it's been pretty good.
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One, I think you're painting with a very broad brush.

Two, I don't think Van's has any interest in replicating 43.13 specific to its kits. Builders have the responsibility to educate themselves and make appropriate choices. After all, building an EX/AB is supposed to be for education and recreation. Having Van's give a recipe for everything is more like monkey see, monkey do, than a learning process.
 
yetti said:
Certified plane, certified mechanic, certified oil cooler. I would guess the channel locks that did this to the certified AN pipe fitting were not certified.
elbow.jpg
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That A&P's boss should tighten his nuts with the same pair of Channel Locks.:mad2: They do make sockets for installing those fittings.
 
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