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Debris in my fuel tanks

1flyingyogi

Well Known Member
I have no idea what these white flakes are or where they came from! I saw these just when I was about to fill up today. I cancelled my fuel request and will drain the tanks tomorrow and try to fish them out with some kind of long tweezers or thin needle nose pliers. Or any other tools would be good for this? I've seen these long claw-type tools, but don't know what they're called or where to get them...

These things look like paint flakes - the only thing is my plane is not painted white anywhere. The second possibility is they're pieces of teflon, but the only place where I have a *tiny* bit of teflon is around the threads on the fuel drain plugs. But I really don't think it's this either. Any ideas what these things are and how they got in my tanks? They really look like paint flakes.

I've had this plane for over two years and have never seen anything like this. I usually look inside my tanks before I fill up. I installed fuel injection in March. Last month/ about 10 hrs ago I inspected the fuel filter and it was clean. Any ideas??

Here are the photos: https://drive.google.com/open?id=1ANfB50F0G0djLYzbLVMFWp5HkWwL8qy5
 
Send them to Weeps no More. Expensive but they do an excellent job.

+1

It looks like slosh to me as well. I had it in the -10 I bought - Weep no More fixed it and did a great job! No more leaks, nor more slosh, no more white flake So!
 
I just contacted Paul at Weep No More and you're right about it not being cheap. Plus I need to add the cost of shipping from California...

I've been told by two builders at my field (an RV4 and the other RV8) that it might be better just to build new tanks. One guy offered to help me do it. So I might go this route. I'll take that opportunity to add a flop tube and replace a bad sender. Who knows, it might be fun and I'll definitely learn a lot.

In the mean time, the flaking is not that bad. I removed about half a dozen from each tank today. I'll keep a close eye on how it looks in there at every fill-up. But a permanent fix will be in place in a few weeks, whether that be sending them out to WNM or building new tanks.
 
slosh

Brian, I wouldn't fly the airplane with any presence of slosh. Here's a thread on this: http://www.vansairforce.com/community/showthread.php?t=83751&highlight=slosh :mad:
My mechanic did the first tank and said he'd never do that again, so I sent the other to Weep no more, and they did a great job. If you go for the tank rebuild, you may find getting the tanks to fit a little challenging and you might be down from doing your loops longer than you'd want.
Good luck,
Bill
RV-4 slider
Lower AL
 
Brian,

We had a J3 Cub with an 18 gallon aluminum aux tank in one wing (always fun flying sideways after filling that baby up!). After filling the tank one day, I noticed a white plastic bag floating on the surface in the tank.
“How the heck did that get in there?” Stuck a pair of long pliers into the filler neck and pulled out a 6 inch diameter piece of slosh. Drained fuel, removed tank. Shoved a garden hose in it and preceded to wash hundreds and hundreds of small bits from the tank. It’s like all the slosh decided to release at once. Never even knew slosh was in there.

The plane was built in 2006.
Anyway, remember the key is not when the aircraft received it’s original A/W Certificate.
Maybe the tanks were done years prior. Our RV6 was started in 1989. Yet,
it’s registered as a 2016 build.

If it is slosh, please be happy that you discovered it while on the ground.
Others have been less fortunate.

All the best,
Lorne
 
DON'T fly it! You are just asking for trouble. The sloshing compound seems to have a finite life, works well for a period of time and then it just starts to come loose. I think you will find the problem will get worse very quickly.
 
Teflon

There is never a reason to even use a tiny bit of Teflon tape anywhere on fuel items. there are other ways to seal a seeping fitting. It only takes a tiny bit to down an airplane.
 
Ok. I hear what you guys are saying. My logic was that the flakes of slosh are pretty big and there's no way they'll get through the screens at the fuel pick up and then after that, there's the fuel filter, and after that, there's an even finer screen at the fuel servo inlet. So there's no way the flakes (especially if it's just a few pieces flaking off once in a while) will get all the way through and cause a problem. Is my judgment off?? I was going to limit my flying but not ground the plane completely and then get this fixed for good in about two weeks when I have more time.

Yesterday after fishing out all the flakes, I flew for an hour including aerobatics and when I landed didn't see any more flakes.

I spoke to some other RV guys with the same problem and one of them said the builder of his plane has been fishing out flakes every once in a while for twenty years and apparently it didn't bother him enough to remove the slosh and reseal. And another guy is using additional filters upstream of the fuel selector to catch the flakes.

I guess I can be extra-cautious and just ground the plane until this is fixed. For me not flying takes a huge amount of self-control! It's not easy. ;)
 
There is never a reason to even use a tiny bit of Teflon tape anywhere on fuel items. there are other ways to seal a seeping fitting. It only takes a tiny bit to down an airplane.

Thanks for the info. I used Permatex on the fuel drain plugs because I saw that it was there before I removed. I asked an AP and he said it's ok to use it there. But later on I was told by other APs that it's not necessary and I shouldn't do it. I will remove it.
 
Ok. I hear what you guys are saying. My logic was that the flakes of slosh are pretty big and there's no way they'll get through the screens at the fuel pick up and then after that, there's the fuel filter, and after that, there's an even finer screen at the fuel servo inlet. So there's no way the flakes (especially if it's just a few pieces flaking off once in a while) will get all the way through and cause a problem. Is my judgment off?? SNIP..

The short answer is yes.

Just because the screens and filters will keep the flakes out of the engine does not mean the flakes will not clog the screen or filter and fuel starve the engine.

Consider how you would explain to your insurance company why you had an engine out landing - including your decision to fly the plane with a known fuel problem.

Ground the plane and fix the tanks.
Carl
 
Ok. I hear what you guys are saying. My logic was that the flakes of slosh are pretty big and there's no way they'll get through the screens at the fuel pick up and then after that, there's the fuel filter, and after that, there's an even finer screen at the fuel servo inlet. So there's no way the flakes (especially if it's just a few pieces flaking off once in a while) will get all the way through and cause a problem. Is my judgment off??

Your judgment is overlooking the possibility of two or three small flakes completely obstructing the fuel pickup screen in the tank. Yes, it is unlikely that both tanks would be starved at the same time but fuel starvation at 200' over the departure end of the runway will not end well.......

The tanks need to be fixed.
 
Using your logic, then it would be OK to fuel your plane with known contaminated fuel, sump it, and then hope the filter(s) catch the rest. Please heed the advice given in this forum. Should there be an incident, by virtue of your posting on this forum, the FAA may well be able to document operation of the aircraft with a known deficiency. Take the case of the guy with the Subaru powered RV-10 who augered in. The NTSB report makes refference to his posts on this forum. Big Brother IS watching!
 
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That stuff can also come off in sheets that could easily clog the fuel pick up. I would not fly it and you are smart to ground it. Building new tanks is a good option if your plane was from a pre punched kit otherwise the tank screws are going to be a problem to line up. Some have cut holes in the back of the tanks and cleaned it out, I don?t know how they ever got it all. I tried it on one bay and gave up, very time consuming and difficult. Send them to Paul.
 
Teflon is a brand name for PTFE. Having said that, Teflon *tape* is the stuff that's been found to cause clogs in not just fuel systems, but oil systems, as well. I don't recall ever seeing any issues (outside hangar lore) with PTFE/Teflon laced sealants.

Having said *that*... if you read the docs on that product
https://www.permatex.com/products/thread-compounds/thread-sealants/permatex-thread-sealant-with-ptfe/
you'll notice that it doesn't mention gasoline in its uses. Permatex Aviation Form-a-Gasket #3 *is* listed for gasoline, and it's rated for machined surfaces and for threads.
https://441py33rout1ptjxn2lupv31-wpengine.netdna-ssl.com/wp-content/uploads/tech_docs/tds/80018.pdf
Note that the solvent in the sealant (and several other Permatex sealants) is alcohol. This lead me to worry about whether it's good for E-gas. I called their tech line about one of their other PTFE pastes that *is* rated for gasoline. The person who answered said that it is safe for E-gas applications.

edit: Even though the name includes 'Aviation', it's available from most auto parts suppliers.

Charlie
 
Teflon is a brand name for PTFE. Having said that, Teflon *tape* is the stuff that's been found to cause clogs in not just fuel systems, but oil systems, as well. I don't recall ever seeing any issues (outside hangar lore) with PTFE/Teflon laced sealants.

Having said *that*... if you read the docs on that product
https://www.permatex.com/products/thread-compounds/thread-sealants/permatex-thread-sealant-with-ptfe/
you'll notice that it doesn't mention gasoline in its uses. Permatex Aviation Form-a-Gasket #3 *is* listed for gasoline, and it's rated for machined surfaces and for threads.
https://441py33rout1ptjxn2lupv31-wpengine.netdna-ssl.com/wp-content/uploads/tech_docs/tds/80018.pdf
Note that the solvent in the sealant (and several other Permatex sealants) is alcohol. This lead me to worry about whether it's good for E-gas. I called their tech line about one of their other PTFE pastes that *is* rated for gasoline. The person who answered said that it is safe for E-gas applications.

edit: Even though the name includes 'Aviation', it's available from most auto parts suppliers.

Charlie

Thanks for the clarification Charlie. I used Permatex #14 b/c that's what Don recommended when I installed my Fuel Injection system. That and Loctite 565 PST.

As for needing sealant on the fuel drain plugs, I've been getting different answers from different people. Is it needed/ recommended? When I took mine off there was some white sealant on the threads so I figured I should also put it back with sealant and used the Permatex. But is it necessary??
 
Thanks for the clarification Charlie. I used Permatex #14 b/c that's what Don recommended when I installed my Fuel Injection system. That and Loctite 565 PST.

As for needing sealant on the fuel drain plugs, I've been getting different answers from different people. Is it needed/ recommended? When I took mine off there was some white sealant on the threads so I figured I should also put it back with sealant and used the Permatex. But is it necessary??

You don?t need sealant on a straight pipe thread. The threads are designed to purposefully gall and self seal, as long as you don?t back them off. A lubricant is recommended. I use fuel lube. There is nothing wrong with an appropriate thread sealant as that provides lubrication as well and has the added benefit of sealing if you have to turn the fitting for alignment purposes, like on brake cylinders, oil cooler fittings, etc....
 

Good resources. I should have been more clear. ?Straight? fittings that have no orientation do not necessarily need sealant, or any fitting you can tighten and not loosen back up to align. They are still tapered in this application.
 
FUEL TANK ( Slosh)

Brian

Before you order the parts to build new tanks why don't you open up the tanks ( Either via the fuel sender cover or open the back of the tanks )

So that way you will be able to see the extent of the sloshing problem and be able to judge if you're able to clean it yourself or at that point decide to build new tanks..

Most likely cheaper and faster to do..

YMMV

Bruno
 
Slosh removal

In the past builders have cut holes in each bay of the tank
using a fly cutter and then reaching in and removing the slosh
compound then building a flange similar to the end flange and
resealing.
 
You don’t need sealant on a straight pipe thread. The threads are designed to purposefully gall and self seal, as long as you don’t back them off. A lubricant is recommended. I use fuel lube. There is nothing wrong with an appropriate thread sealant as that provides lubrication as well and has the added benefit of sealing if you have to turn the fitting for alignment purposes, like on brake cylinders, oil cooler fittings, etc....

I disagree Jon

Though NPT threads are an interference fit, it does not produce an entirely sealed path through the threads. (There are specialty threads that do this but standard AN type fitting don't have them.... a google search of NPTF threads will provide a lot of info).
Standard NPT threads will always have a small spiral leak path that needs a small amount of sealant to assure no leak. That is why Sect 5 of the construction manual recommends sealant be used.
 
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I disagree Jon

Though NPT threads are an interference fit, it does not produce an entirely sealed path through the threads. (There are specialty threads that do this but standard AN type fitting don't have them.... a google search of NPTF threads will provide a lot of info).
Standard NPT threads will always have a small spiral leak path that needs a small amount of sealant to assure no leak. That is why Sect 5 of the construction manual recommends sealant be used.

I trust you Scott.
Perhaps the steel valve into the aluminum boss makes a difference. Anyway, I have had no issues with only fuel lube as a lubricant for the drain valves. No leaks, 12 years, and they have been in and out many times. Maybe I?m just lucky ;)
 
I trust you Scott.
Perhaps the steel valve into the aluminum boss makes a difference. Anyway, I have had no issues with only fuel lube as a lubricant for the drain valves. No leaks, 12 years, and they have been in and out many times. Maybe I?m just lucky ;)

Like Mike said, fuel lube will also act as a sealant (particularly with fuel) since it will fill small gaps in the threads, so it works in the case of fuel drains, but it is not recommended as a general sealant for all pipe thread joints.
 
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