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  #1  
Old 03-17-2016, 06:44 AM
ShortSnorter ShortSnorter is offline
 
Join Date: Dec 2013
Location: NOLA
Posts: 351
Default Not your typical fuel tank woe

After agonizing over to wet rivet or not, sealant dispensing methods, and everyone opinions, I completed my fuel tanks back in November and the initial leak test with soapy water and balloon passed with flying colors. About a week or so ago I ran across a thread from a builder who was having issues with producing acceptable tubing flares. It was then I learned that I used the wrong flare set (automotive) when making the vent lines in for the tanks. That's when I went down another path of endless thread scouring about potential vent blockages/leakages etc. I was worried that although leak free, I may leak fuel through the improper vent fitting once the vent fitting was submerged in fuel. My curiosity couldn't take it anymore, so I decided to do another leak test with Avgas. Long story short, no leaks from the inboard rib vent fitting when submerged in fuel. Which brings me to......

While inspected each rivet in the tank for blue dye, I was scraping off bits of dry proseal from around the rivets. My heart sank when I found this:





It seems that during my wet riveting, proseal madness, I overlooked a rivet. This hole is filled with dry proseal and is leak free. It is just far enough away from the filler cap that I can not reach it. Here is a picture I tried to snap holding a mirror through the filler neck (the red in the lower left is the filler neck). The red arrow points to the pick piercing through the sealant.



Here are my initial thoughts in order of least to most invasive:

1) Do nothing other than fill the dimple completely flush with sealant and pretend like it never happened.

2) Put a blind rivet in and attempt to smoosh a big dollup of sealant on the shop head using some sort of reaching device (i.e. mirror, etc)

3) Cut an access hole in the back and put the the correct rivet in place. (This seems like overkill)

Any other ideas or suggestions? I hate to cut into a leak free tank just for the sake of one rivet.

Thanks in advance!
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  #2  
Old 03-17-2016, 06:53 AM
Pat Stewart Pat Stewart is offline
 
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Location: Granbury Texas
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Default

The RV12 uses a special blind rivet for its fuel tank and you install it wet. You might talk with Vans but this seems like an option. A second option is to install the correct rivet. It looks close enough to the fuel cap to get a small bucking bar inside.
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Last edited by Pat Stewart : 03-17-2016 at 06:55 AM.
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  #3  
Old 03-17-2016, 08:06 AM
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rv8bldr rv8bldr is offline
 
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Location: Pakenham, Ontario, Canada
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Default

Quote:
Originally Posted by Pat Stewart View Post
The RV12 uses a special blind rivet for its fuel tank and you install it wet. You might talk with Vans but this seems like an option. A second option is to install the correct rivet. It looks close enough to the fuel cap to get a small bucking bar inside.
The AK-42H rivet is a flush, closed ended pull rivet. You will have to drill the hole out to 1/8", then use a countersink/hand deburring tool to bevel the hole enough to make the rivet sit flush. However, the tank skins are quite thick, so you shouldn't have any issues there. Just do a little at a time and test with the rivet until it is flush.
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  #4  
Old 03-17-2016, 08:22 AM
F1R F1R is offline
 
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A custom bucking bar holder with a small bucking bar should allow a normal rivet to be used. Move on to other jobs and think it over for a while.
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  #5  
Old 03-17-2016, 09:00 AM
sblack sblack is offline
 
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waiting and thinking is always helpful. The challenge is being able to sleep
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  #6  
Old 03-17-2016, 09:14 AM
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rvbuilder2002 rvbuilder2002 is offline
 
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Location: Hubbard Oregon
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Quote:
Originally Posted by rv8bldr View Post
The AK-42H rivet is a flush, closed ended pull rivet. You will have to drill the hole out to 1/8", then use a countersink/hand deburring tool to bevel the hole enough to make the rivet sit flush. However, the tank skins are quite thick, so you shouldn't have any issues there. Just do a little at a time and test with the rivet until it is flush.
Quote:
Originally Posted by F1R View Post
A custom bucking bar holder with a small bucking bar should allow a normal rivet to be used. Move on to other jobs and think it over for a while.
Either of these suggestions are good options.

The first one has been done successfully many times.
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  #7  
Old 03-17-2016, 09:59 AM
rwarre rwarre is offline
 
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Default Good advice

I agree with the sleep method. After several days of thinking about my problem, I have always come up with a solution that works.
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  #8  
Old 03-17-2016, 10:04 AM
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Mike S Mike S is offline
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I have used the special closed end pop rivet to fix a leak on the bottom of my tank.

This is the fix recommended by Vans.
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  #9  
Old 03-17-2016, 06:39 PM
ShortSnorter ShortSnorter is offline
 
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Gents - I appreciate all of the valuable feedback. I think I'm going to go the blind rivet route for two reasons: 1) Its fast and easy; 2) I could see dropping a bucking bar or whatever into the tank and dinging it up (even though its the bottom skin)

Next question: Should I pretty much use the same procedure for riveting the Z-Brackets and swirl the rivet in sealant prior to insertion and then attempt to reach with something and dollop sealant on the shop head of the rivet for good measure?
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  #10  
Old 03-18-2016, 07:08 AM
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rv8bldr rv8bldr is offline
 
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I certainly would.
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