Fuel contamination corrosion x treatment

[markazzarito]

Two years ago at annual my AP applied an anti corrosion treatment inside the wings of my plane. Ever since the seams and rivets have been weeping the stuff. I read this is due to over application however it doesn’t really bother me. My concern however is that I recently discovered an oily substance in my fuel sample. It’s obvious to me its leaching into the fuel tank much like it does out of the seams in the wings (the tanks are not otherwise leaking). My question is does anyone have experience with this and does anyone know if the corrosion treatment is dangerous in the fuel? I cant seem to find any information as to whether or not anti corrosion treatment leaching into the fuel tanks is common or safe or needs to be addressed??

Edited November 23, 2020 by markazzarito

[carusoam]

Weeping rivets caused by corrosionX is expected...

It is a sign of how it can weep into really tight spaces and bring aluminum oxide dust with it... which takes a normal amount, so not a side affect of over spraying...

Chances of it getting past the sealant in tank rivets is a two step process...

Not much gets past a rivet... then it would have to breach a layer of sealant...

 

If you are seeing an oily substance in your fuel samples...

How is it getting there?

Oil typically floats... 

Tank sumping is usually done at the bottom of the tank...

Got any pics?

Oil getting into fuel is really remote...

One source can be from mechanical fuel pumps...but that is pretty far down stream too...

Got any CorrosionX you can intentionally put in a fuel sample cup to see if it appears the same?

PP thoughts only, not a mechanic... My M20C got sprayed with a lot of CorrosionX while it lived outdoors...

Best regards,

-a-

[chriscalandro]

Unlikely.

[Prior owner]

100LL is a very effective solvent (hence the nick name “ramp solvent”). I’m not sure that you would be able to detect small quantities of dissolved oil in your fuel. If CorrosionX managed to make its way into your fuel tank, then avgas would be coming back out through the rivet hole(s)! ... are you getting fuel staining in the wing, outside of the tank?

As mentioned above, weeping through the rivets is a normal occurrence.

On a side note, I have seen wing skin rivets weeping brownish fluid months after a tank strip & seal- not fuel, but small amounts of Polygone tank stripper that became trapped between the skin and the ribs because it didn’t flush completely out with water after application. Polygone will wrinkle/blister the paint around the weeping rivet. 

 

 

[PT20J]

It seems unlikely that Corrosion X would get into the fuel tank.

So, the question is: what's the "oily" substance? It's hard to tell without knowing how much and how oily. The usual oily substance that gets into a fuel tank and finds it's way to the sump (because it's denser than avgas) is Jet A. 

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[0TreeLemur]

3 hours ago, PilotCoyote said:

100LL is a very effective solvent (hence the nick name “ramp solvent”). I’m not sure that you would be able to detect small quantities of dissolved oil in your fuel. If CorrosionX managed to make its way into your fuel tank, then avgas would be coming back out through the rivet hole(s)! ... are you getting fuel staining in the wing, outside of the tank?

As mentioned above, weeping through the rivets is a normal occurrence.

On a side note, I have seen wing skin rivets weeping brownish fluid months after a tank strip & seal- not fuel, but small amounts of Polygone tank stripper that became trapped between the skin and the ribs because it didn’t flush completely out with water after application. Polygone will wrinkle/blister the paint around the weeping rivet. 

 

 

That is very interesting.  Today while cleaning I noticed that a few of the rivets on the top of the fuel tank are showing some brown staining under the paint.  What you describe explains that.   Drat.  I guess that means the paint will be coming off those spots one of these days.

[markazzarito]

Thanks for the replies! Seems it may not be the corrosion treatment.. the most likely culprit is the Jet A though i have flown on the tank at altitude without issue thus far... i will follow up with a picture of the fuel sample its not extremely apparent and looks like little droplets in the fuel sample after the sample cup has been emptied it appears to have a textured clear grit in it. 

[carusoam]

Pics will definitely be helpful...

One of the things that is hard to describe is how some things are miscible in various solvents...

Oil and gas definitely float on water...

Oil will typically dissolve in gasoline and spread around the tank un-noticeably...

Jet fuel can be very hazardous to your engine... detonation and piston melting on departure... depending on how much jet fuel you got...

Getting matching glass jars and samples helps for visual comparison... color check if you suspect contamination...

 

Small beads that sink to the bottom... often reddish in color... high probability of water and a combination of rust from mild steel fuel necks... (typical challenge of my old 1965 M20C...)

There is often very little water in our fuel tanks, it can be resident there for a very long time... one rust speck can add color to the small amount of moisture...

This is possible at the lowest corner of the tank... below the sump drain...

Pics always appreciated...

Best regards,

-a-

[Prior owner]

1 hour ago, 0TreeLemur said:

That is very interesting.  Today while cleaning I noticed that a few of the rivets on the top of the fuel tank are showing some brown staining under the paint.  What you describe explains that.   Drat.  I guess that means the paint will be coming off those spots one of these days.

If your staining is in fact trapped Polygone, the good news is that it won’t eat the aluminum...

[clh]

So, you are finding a brown gooey substance...  Over time, avags will oxidize, and Polymerize to create a brown looking, gooey mess.   I would be very concerned if you had jet-a contamination.    It really sounds like a very slow seep over time. 

If it appears in the fuel sample...  it could be from the seep.  But, it should be a very minute amount of material

 

[chriscalandro]

4 hours ago, markazzarito said:

the most likely culprit is the Jet A 

LOLZ WHUTT?

 

 

Sounds a lot like this airplane should not be in the air.

 

[tmo]

7 hours ago, markazzarito said:

the most likely culprit is the Jet A

Please say you said "avgas" and siri turned it into "jet a"

[markazzarito]

Here are a couple pictures of the sample. Looking down into the cup it appears there is a faint oil slick at the bottom a little hard to tell in the photo. From the side it looks like there are tiny bubbles sitting at the bottom of the cup below the fuel this is exaggerated in the photo. When the sample is emptied whatever is creating the bubble look remains at the bottom of the sample cup.

[markazzarito]

Well at this point it appears to be a non issue! Whatever it was is gone after draining a couple gallons through the sump.

[Hank]

Did you wipe the bottom of the sample cup?

[chriscalandro]

Where are you located?  Just want to make sure you aren’t anywhere near me. 

[carusoam]

That looks like A ton of water...

at the bottom of the cup... notice how it doesn’t have the usual blue color...

Test: If you put some water into that sample... where does it go?  This is also known as the spit test...

When your spit sinks... it passes through the fuel to where the water is and spreads out...

 

Fuel doesn’t form this two phase partition line... not jetA, or other hydrocarbon... or alcohol...

 

This definitely isn’t an amount that could seep through a rivet that is still in place... so it is not properly used CorrosionX...

Black bits look like rust particles...

Send camera into the tank... and catch some video looking back at fuel neck where the cap locks in place...

It probably isn’t shiny metal under there any longer... expect to see the source of black bits there...

You might check to see when the last time the two orings in each gas cap were replaced... it might be time for a couple more... four total...

Oddly as goofy as Chris’ statements are above... he knows this challenge pretty well...

Chris, did you ever post the cause/solution or was that a pm only kind of thing... 

The good news... if you find black bits on the fuel neck... this part is replaceable with a new part made from Stainless Steel...

Note... my 65 M20C had the fuel neck rust through... a crack formed and allowed a lot of rain water to enter the fuel tank.  

• The water doesn’t absorb the blue color, but gets cloudy from something else...
• The rust bits mostly sink to where the sump drains them out... often sticking in the sump drain keeping it dripping...
• Some rust bits get to the fuel sump and collect there...
• It is possible for these bits to go further towards the engine... this would be bad.

It might be possible that a magnet might hold those tiny black bits... they aren’t pure iron oxide... they may still have iron atoms that may be magnetic...(?)

PP thoughts only, not a mechanic... or organic chemist...

Best regards,

-a-

 

[chriscalandro]

PM only after the fuel cap debacle. 
 

for 100% sure I don’t want anything to do with troubleshooting this after the responses that were given. 
 

sounds like there is potentially a lot wrong here and the entire story isn’t being told. 

[markazzarito]

8 hours ago, chriscalandro said:

Where are you located?  Just want to make sure you aren’t anywhere near me. 

And why is that?

[markazzarito]

8 hours ago, carusoam said:

That looks like A ton of water...

at the bottom of the cup... notice how it doesn’t have the usual blue color...

Test: If you put some water into that sample... where does it go?  This is also known as the spit test...

When your spit sinks... it passes through the fuel to where the water is and spreads out...

 

Fuel doesn’t form this two phase partition line... not jetA, or other hydrocarbon... or alcohol...

 

This definitely isn’t an amount that could seep through a rivet that is still in place... so it is not properly used CorrosionX...

Black bits look like rust particles...

Send camera into the tank... and catch some video looking back at fuel neck where the cap locks in place...

It probably isn’t shiny metal under there any longer... expect to see the source of black bits there...

You might check to see when the last time the two orings in each gas cap were replaced... it might be time for a couple more... four total...

Oddly as goofy as Chris’ statements are above... he knows this challenge pretty well...

Chris, did you ever post the cause/solution or was that a pm only kind of thing... 

The good news... if you find black bits on the fuel neck... this part is replaceable with a new part made from Stainless Steel...

Note... my 65 M20C had the fuel neck rust through... a crack formed and allowed a lot of rain water to enter the fuel tank.  

• The water doesn’t absorb the blue color, but gets cloudy from something else...
• The rust bits mostly sink to where the sump drains them out... often sticking in the sump drain keeping it dripping...
• Some rust bits get to the fuel sump and collect there...
• It is possible for these bits to go further towards the engine... this would be bad.

It might be possible that a magnet might hold those tiny black bits... they aren’t pure iron oxide... they may still have iron atoms that may be magnetic...(?)

PP thoughts only, not a mechanic... or organic chemist...

Best regards,

-a-

 

Great point on the small potential rust bits! Im going to inspect the tanks with a camera. The photos greatly exaggerate the bubble appearance and cant depict what appeared to be some sort of gritty clear residue left on the cup after the sample was dumped. I have put small amounts of water in a clear sample to test and the look was not close the good news is after draining through the sump im now getting clear samples. Thanks for your help sorry to have scared you with my incompetence ill try not to fall out of the sky on you Chris! 

Edited November 24, 2020 by markazzarito

[LANCECASPER]

On 11/23/2020 at 11:05 PM, markazzarito said:

Great point on the small potential rust bits! Im going to inspect the tanks with a camera. The photos greatly exaggerate the bubble appearance and cant depict what appeared to be some sort of gritty clear residue left on the cup after the sample was dumped. I have put small amounts of water in a clear sample to test and the look was not close the good news is after draining through the sump im now getting clear samples. Thanks for your help sorry to have scared you with my incompetence ill try not to fall out of the sky on you Chris! 

The contamination came from somewhere. If you regularly sump and you just noticed it on this last batch of fuel I would definitely let the people you bought it from know this. If you don't regularly sump and just noticed it, it could be sediment from who knows when. 

Near my home base there was a pump on their self serve fuel system that was coming apart and putting small shavings of metal in the avgas - not good. They were notifying people by the N-numbers that the they entered when pumping their own fuel. 

If that's water in your fuel, how long since you changed the O-rings on your fuel caps?

[carusoam]

+1 for sumping every time... for a lot of reasons...

Extra attention to this particular detail to see if it returns...

 

There are so many types of fuel accidents... MS has seen a lot...
 

It is nice to know we haven’t let one slip by... sort of erring on the side of caution...

I have seen more than I would like in my own planes... over the years...

I’m glad you took the time to post the details!

Best regards,

-a-