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  #1  
Old 06-24-2018, 06:12 PM
1flyingyogi 1flyingyogi is offline
 
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Location: Long Beach, CA
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Default Slosh mystery

We removed one tank and took the cover plate off to see what we could find. Surprisingly, as far as I can tell, there is NO sloshing compound anywhere. All I can see is gray sealant (Proseal?) at the seams and joints. I did see lots of white flakes (assumed to be slosh?). So where did these flakes come from?? Here are the photos of the inside of my tank. I used an inspection camera to look in all the compartments of the tank and only saw gray sealant. There's nothing white except the flakes.

https://drive.google.com/open?id=1wL...EIcoek1Wl5wT3r

And here's the original thread on this topic:

http://www.vansairforce.com/communit...62#post1268362
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  #2  
Old 06-24-2018, 07:17 PM
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Sam Buchanan Sam Buchanan is offline
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First...glad to see your tanks aren't sloshed, that is going to prevent you from enduring a major hassle.

The only possibilities I can think of:

1) The tank had a small amount of slosh at some point....maybe as an attempt at a spot repair of a leak????

2) The contaminant was introduced during refueling.

If you don't have any leaks you can give the tanks a good flushing and continue to fly them. It is good you pursued this, many accidents have occurred due to fuel supply problems.
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  #3  
Old 06-24-2018, 07:23 PM
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I looked at Brian's tank today and I agree, there is no coating on the inside save for the pro seal on the seams and rivets. The flecks seem to be loose and I too think he can flush the tanks and put it together.

-Marc
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  #4  
Old 06-24-2018, 07:27 PM
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Carl Froehlich Carl Froehlich is online now
 
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I wonder if some of the inside tank got a coat of primer by mistake.

Carl
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  #5  
Old 06-24-2018, 08:28 PM
VA Maule VA Maule is offline
 
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I'm going to side with Sam on this one and suspect that somewhere in the fuel supply chain that material came to be. Backtrack where you fueled up the last several times before you noticed the flakes in your tank. Airplanes aren't the only things that get tanks sealed.
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  #6  
Old 06-26-2018, 04:37 AM
Northernliving Northernliving is offline
 
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Perhaps more work than it's worth at this point, but wonder if you could find a lab to test the material. Scary to think that it might have come your fuel supplier and if so, how many other planes are contaminated with the same. Backtracking where you fueled, as VA_Maule suggested, to see if you could find the source is an excellent idea.

Brian
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  #7  
Old 06-26-2018, 08:23 AM
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Raymo Raymo is online now
 
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Default Bugs?

I recently read an article on micro-organisms that can get into the fuel system and wreak havoc.

http://clean-fuels.net/got-bugs-in-your-fuel
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  #8  
Old 06-26-2018, 11:28 AM
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az_gila az_gila is online now
 
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It might still be slosh.

IIRC the initial recommendation for applying slosh was to simply "slosh it around" the completed tank.

Later the technique was to simply brush it on as an extra layer over the prosealed seams only.

This later method would have used much less slosh and it probably would not come off in sheets, which was the failure mode for the "slosh it" technique.
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  #9  
Old 06-26-2018, 12:50 PM
xblueh2o xblueh2o is offline
 
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Quote:
Originally Posted by Sam Buchanan View Post
First...glad to see your tanks aren't sloshed, that is going to prevent you from enduring a major hassle.

The only possibilities I can think of:

1) The tank had a small amount of slosh at some point....maybe as an attempt at a spot repair of a leak????

2) The contaminant was introduced during refueling.

If you don't have any leaks you can give the tanks a good flushing and continue to fly them. It is good you pursued this, many accidents have occurred due to fuel supply problems.
The little bit I know about fuel farms and the requirements for them I find it hard to believe any solid contaminant as large as the flakes in the pictures could be pumped in. Anything is possible but it doesn't seem likely.
I think your first guess or Gill's "belt and braces" option of brushing slosh over pro seal are more likely.
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Last edited by xblueh2o : 06-26-2018 at 12:52 PM. Reason: Mongo no type good. Much gooder now.
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  #10  
Old 06-26-2018, 01:08 PM
1flyingyogi 1flyingyogi is offline
 
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Location: Long Beach, CA
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Default Update

I spent the day yesterday removing the other tank, removing the access plates on both tanks which was not easy. I flushed out both tanks really well and afterwards inspected with my camera just to make sure I got it all out. The right tank had considerably more flakes than the left. Interestingly, the right tank was also the one that looked like there *might* have been slosh in some specific areas that was brushed on and then later removed - but maybe not removed completely?? This is just purely a guess based on how it looked. I'll upload photos later.

I spent some time digging around and found the builder's phone number and had a nice chat with him earlier today. He sounded like a really nice guy who absolutely loves to build. He started two more projects after the RV4 (which he won a best home built award for), but never finished due to health problems. If feel bad for him. And as for the fuel tanks, he said he did not use slosh. I asked him again if he might have used it even in a few small areas and he said no, although the tone of his voice was not very convincing. (Or maybe I'm just reading too much into it)

My best theory for what happened is that the builder used a *small* amount of slosh and then later removed it, but not completely. And the reason why I think this is because of the way it looks - it looks like there was something on the walls of the tank and then wiped off - kinda like when you wipe your kitchen table and the stain has not been completely removed and you can see the trace of it. I took some pictures, but they didn't show well. I'll try to get better ones in a few days. Anyway, this is just a theory. I really enjoyed talking to him and felt he's a really nice guy - but maybe just didn't want to admit the he used slosh?? Again, I might be totally wrong.

I feel like this is more likely than that white stuff coming from the fuel supplier. I get my fuel from the truck at my home airport (CPM) 90% of the time. In May I also fueled at Apple Valley where I did my contest and in April I also got fuel from Monterey, Delano, and Bakersfield. It's pretty unlikely that any of these places had contaminated fuel.

In any case, I'm glad I did not need to send the tanks out to be serviced. I will flush the rest of my fuel system, inspect the injectors, and from now on use a strainer when refueling. I'll also look into getting those flakes analyzed. That will tell a lot.
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