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algrajek

Well Known Member
I got my fuel tanks sealed and foud one rivet in each tank has a leak. I have searched the forum but can't find anythin specific.
Any way of sealing these rivets without cutting into the tank?
Thanks
Al "Nordo" Grajek
 
erm

Ya thats about it unfortunately...Cut a hole in the rear baffle, stop the leak with proseal from the inside and put a patch on.

Frank
 
Van's recommends green (self-wicking) loctite for the occasional rivet leak. It helps if you put a little vacuum pressure in the tank to help suck it in. I'd try this before cutting into the tank.
 
Lets just reiterate that if you decide to pull a vacuum on the tank, keep it very, very little. That tank has a lot of skin area and is surprisingly easy to collapse with negative pressure.
 
There is a fair amount of info on this in the archives - search on "weeping rivet".

The Loctite method appears to work successfully for very small leaks. I used it recently (so far so good). As previously cautioned - keep the vacuum low, around 13 inches of water. You can set up a simple manometer off of the vent line to measure this, as described in one of the archived eaerlier posts on this subject.

erich
 
I used the green Loctite method back in 2003 when I discovered a weeping rivet. I completely drained the tank, put a VERY small vacuum on it with a hand pump attached to the fuel vent, and applied the sealant. The hand pump I used was a $12 fuel pump from the local auto parts store. I did remove paint from the rivet before applying the loctite.

I haven't had a problem in the intervening 5 years.

John Allen
 
I've also used the loc tite leaking rivit fix with mixed results, but it did work on over 1/2 of the rivits I have tried it on.

Good luck. Keep us informed.
 
Where is the leaking rivet? I had a leaking rivet on the rear baffle. The leak was discovered after final assembly. I drilled out the rivet, vacummed the rivet out through the wing root...shoved a little pro-seal up into the hole, covered a 3/32 pop rivet in pro-seal and pop'd it into place. I have had no leaks so far.
 
I used thinned Pro-Seal on a leaking rivet along the leading edge. PS thinned with a little MEK seemed to work well and sucked into the tank after pulling a little vac (not too much though).
 
while we are on the subject...

I am currently pro-sealing my left fuel tank. I am wondering if I should check for leaks BEFORE closing it up with the rear baffle. With the tank in it's cradle, cant I just fill it up with colored water to look for leaks in rivet areas hard to reach once the tank is closed up???
 
I am going to try the loctite as soon as I get it. I could not find it locally, so I have to wait to get it shipped, unless anyone knows any retail outlets that sell it. It actually is a few rivets in the rear baffle, and just one at the very leading edge.
On my other tank I filled it up with water and let it sit overnight and fouind 2 leaks, re sealed them, and its good to go.
Al
 
algrajek said:
I am going to try the loctite as soon as I get it. I could not find it locally, so I have to wait to get it shipped, unless anyone knows any retail outlets that sell it. It actually is a few rivets in the rear baffle, and just one at the very leading edge.
On my other tank I filled it up with water and let it sit overnight and fouind 2 leaks, re sealed them, and its good to go.
Al
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Any decent auto parts store will have a version of green loctite. There are many different (generic) brands.
 
jdmunzell said:
I am currently pro-sealing my left fuel tank. I am wondering if I should check for leaks BEFORE closing it up with the rear baffle. With the tank in it's cradle, cant I just fill it up with colored water to look for leaks in rivet areas hard to reach once the tank is closed up???
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i wouldnt waste my time doing this as the fuel will leak where water will not. it would have to be a large leak for this t work. carefully build the tank and test it as vans suggest. you will be good to go.
 
scard said:
Lets just reiterate that if you decide to pull a vacuum on the tank, keep it very, very little. That tank has a lot of skin area and is surprisingly easy to collapse with negative pressure.
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Along with the warning about pulling a vacuum on the tank, PLEASE make sure you have emptied ALL FUEL & VAPORS from the tank if you are using a vacuum cleaner any where near fuel vapors. The sparks from the motor could and will ruin your day. :eek:
 
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Geico266 said:
There was an article about this very subject. If I remember right only the LocTite brand works well on leaking rivits.
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Permatex brand worked just fine on my one rivet, though time will tell. If there is an article about this, I'd be interested in seeing it. Since I finished my tanks three years ago I haven't seen anything about LocTite being the only brand that works.
 
alpinelakespilot2000 said:
Permatex brand worked just fine on my one rivet, though time will tell. If there is an article about this, I'd be interested in seeing it. Since I finished my tanks three years ago I haven't seen anything about LocTite being the only brand that works.
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It was probably published by Loctite! LOL Glad to hear Permatex works too.

When I said "article" I was not accurate. It was a "How to" web page someone posted a link to. It was a homemade web page with pictures. I searched but could not find it.

I had one rivet that would not stop no matter what I tried and I could not get to it from the inside. It only leaked inflight due to pressure in the tanks. I ended up taking a dime size piece of aluminum sheet and JB Welding a patch over it. Ugly? YES, Leak no. It's on the underside so it actually looks "okay" after I feathers the edges and painted it. If you have a rivet that just won't seal, this will do the trick, but should be a last resort. IMHO.

I would like to know more about the pop rivet repair.
 
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marine tex solution

if you have never used this stuff it is amazing. it hardens like steel and will seal a rivet in no time. did one on the bottom- dried, sanded, then white marine-tex over leaking rivet. you can tape around rivet to contain mess. theres more than one way to skin a cat. :rolleyes:
 
another reply

I drilled out the leaking rivet, (a big no-no) and then put pro seal on a CS'd pop rivet - the tank sealed but now I may have tiny shavings in the tank. I plan to try and flush them out before the fuel goes in.
 
Can't attest to it ( welded tank ) but sounds good. Place an o ring around rivet. fill with proseal ( thinned? ). Place flush rivet set or hammer face over o ring to cover. Strike with a hammer to create pressure to drive proseal into space around rivet. Wipe clean. Seams easy enough for a first try.
 
Slow build RV-9A fuel tanks and weeping rivets.

I have been reading all the old posts and the ones in this thread about "weeping rivets" and wanted to add my two cents as a slow builder. Here is a photo I took of my LEFT fuel tank, which has weeping rivets after three years of flying. I actually found a couple of rivets last year during my annual, but found another one this year and decided to do something about all of them. This photo shows the fuel filler neck and the end of the vent line at the left side of the photo.
DSCF0124.jpg


What is important in the photo above is the view of the first rib and how the shop heads are covered by Pro-Seal I bought from Van's in April 2003 when this construction was happening. The stuff was fresh and mixed by weight to get the correct ratio and cured just fine. Looking back on this photo, I realized that I did the RIGHT fuel tank with more Pro-Seal, and never took a photo of that work. Today, I have NO leaks or stains on any rivets on the RIGHT tank, only the LEFT tank. ALL my leaks are on the bottom skin rivets, not on any rear baffle rivets on either tank or any on the top of my Pearl White wings. The difference is visible along the edge of the flange. Notice the flutes are showing Proseal where I put it on the edge of the flange before clecoes were put in to hold the ribs in place prior to riveting. On the LEFT tank, I did not seal the edges of the ribs with Pro-Seal, just put it in between the rib flange and tank skin.

I washed my rivets in paint thinner in baby food glass jars and only handled them with gloves and hemostats when I swirled each rivet in Proseal before inserting them for riveting. I used a little strainer to recover the rivets from the baby food jars after pouring my solvent into another jar. The rivets were allowed to air dry on clean paper towels before dipping into the Pro-Seal. I did all that stuff the "right way". The difference between my RIGHT tank and the LEFT tank was only one thing! I made sure the edges of the rib flanges were sealed completely at the same time I covered the shop heads of the rivets with Pro-Seal. In all the threads I read on this subject in the archives, no one mentioned doing what I just described.

Now, I know what you are thinking, "IF the rivets were coated in Pro-Seal before being placed in position, why do they leak?" After reading all the posts about how the outside tank skin is cleaned, scuffed, etc. prior to primer and painting, the little bit of Pro-Seal between the factory head of the rivet and dimpled skin may not be there anymore, for whatever reason. That brings me back to the extra Pro-Seal I "slathered" on to the edges of the flanges in my RIGHT fuel tank during construction. My "conclusion" is the fuel stains I have around my bottom tank skin RIB RIVETS are there because I had fuel seepage between the rib and the inside of the tank skin via the flutes and the "minimal" coating of Pro-Seal I had put on the ribs was insufficient in the LEFT TANK only (the first tank I built).

For now, I have a few rivets on my LEFT tank to try the Green Loctite 290 or the JB Weld methods of patching. The details of the day I sealed the LEFT fuel tank are shown on my web page at this URL: http://www.n2prise.org/rv9a010.htm
 
n2prise said:
........In all the threads I read on this subject in the archives, no one mentioned doing what I just described........
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Jerry,

Prosealing is not all that difficult but like they say "A chain is only as strong as its weakest link."

I have considerable production experience working with the stuff and have mentioned the very point you raise on at least two occasions. See the tip "Proseal, the fact and the fiction." That was written after I assembled the leakproof fuel tanks on my -6A.

"I insured adequate squeeze-out (smoothed into an uninterrupted fillet seal) existed around the ribs and skin (and previously installed stiffeners) without any voids whatsoever." http://www.vansairforce.com/community/showthread.php?t=7602

And later, this note after building the fuel tanks for the -8 project and contained within Post #5: "The rest of the session was spent in smoothing the sealer squeeze out into an uninterrupted fillet seal around the ribs." http://www.vansairforce.com/community/showthread.php?t=14125&highlight=proseal+Rick6a

Fillet sealing can be a tedius procedure but in the end, one simply cannot cut corners when it comes to fuel tank construction.
 
Rick6a said:
Fillet sealing can be a tedius procedure but in the end, one simply cannot cut corners when it comes to fuel tank construction.
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Amen.

The last time I was in an S-76 fuel tank, it looked like the last person in there thought he was frosting a cake - I could barely see the bucktails of the rivets.
Take a wild guess why I was in the tank......:mad:
 
Good feedback...

Of course, with those old pictures showing the LEFT tank construction, now I have to do the leak repairs after flying my RV-9A over three+ years. I just wish I had the technique right when I did the LEFT tank. Both of them pressure tested fine with the water manometer checks, but only the LEFT one has any weeping rivets.
 
n2prise said:
Of course, with those old pictures showing the LEFT tank construction, now I have to do the leak repairs after flying my RV-9A over three+ years. I just wish I had the technique right when I did the LEFT tank. Both of them pressure tested fine with the water manometer checks, but only the LEFT one has any weeping rivets.
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Jerry,

If you are going to remove the tank from the airplane anyway, may I suggest a much easier fix than tearing into it? I cannot recommend the following solution if the tank is not to be removed from the airplane because the inevitable FOD generated is certain to wander about inside the tank and is never a good thing. If you do remove the tank, you can get all the FOD out either through the filler neck, access plate or both. Again, I do not recommend this procedure if you are not going to remove the fuel tank:

#1. Drill out offending rivet(s). (Tip: Have someone hold a vacuum cleaner next to the hole while you drill to help keep chips from falling into the tank.)

#2. Ream those holes up to .125. ( Again, use a vacuum cleaner.)

#3. Machine countersink the dimples slightly to accept Cherry CR3212-4-? blind rivets. Use a grip gauge to determine correct grip length. ( Yup, vacuum cleaner.)

#4. Liberally coat (or dip) the shop end of the Cherry rivet and coat the dimpled/machined countersink in proseal, then insert fastener into the hole and set. The idea is to encapsulate the shop head of the rivet as much as possible. Try to avoid the temptation to remove the proseal oozing out from around the countersink. If you must remove a blob of it, wipe it away with a clean towel or rag but DO NOT use solvents of any kind. The remainder will clean up well enough after the proseal has set up.

#5. AFTER the proseal has set up, do whatever you can to remove all the FOD from inside the tank. Turn the tank upside down and shake it if you have to. Account for every rivet shop head that you drilled out. Flushing out the tank wouldn't hurt a thing. When you are certain you have removed all the FOD, reinstall the access plate and you should be good to go.

Bear in mind, this fix should work for the occasional and random WEEPING rivet, but if the problem is more significant than that, opening up the tank is best.
 
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Not removing the fuel tank!

I had no intention of removing or opening the tank. This will be an external fix for sure. I had a local A&P give me the same advice you just gave. Thank you! I posted the old photo of my LEFT tank construction for those that are still SLOW building wings and tanks.
 
rivet leaking in fuel tank

Hello Al,

I recently consulted Van's re: a single leaky rivet after the baffles were installed. The rivet is located right next to the baffle on the upper leading edge, in the middle of the tank, so it cannot be reached on the inside with a bucking bar. I did test my tank with water prior to installing the baffle, but I didn't test all the way to the top where this rivet is located. The water test did permit me to discover leaks with other rivets which I corrected. Once the baffle was installed I checked for leaks by filling with air and plunging the tank in the swimming pool and checking for air bubbles. This confirmed proper installation of the baffle on one tank and my final leaking rivet on the other.

During the build I was really careful about filets and dabbing Proseal on each shop head.

Van's suggested the locktite method and a new product called Oyl stik, supplied by La-co http://www.laco.com/productDetail47.aspx

Ordered mine from : http://www.markal.com/

Haven't received it, so I haven't tried it.

They also suggested the blind rivet method, however I would be using the AK-42H, which is the countersunk version of the AD-41H used in the rear baffle.

You may want to consider the Oyl stik and if you wish I will let you know the result once I receive and try the product.

regards,

Normand
 
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