Paint Blisters/Fuel Tank Rivets

[DanH]

Originally Posted by WildThing

My -8A QB has a herd of fuel tank rivet blisters. Not going to bother with them at this time, but wondering if sloshing is the only way (yet) determined to correct the issue?

http://www.vansaircraft.com/pdf/sb11-9-13.pdf

[g zero]

Dan , on the quick build tanks and others that you have seen with blisters are they lacking total encapsulation of the shop heads ?
Tom

[DanH]

Originally Posted by g zero

Dan , on the quick build tanks and others that you have seen with blisters are they lacking total encapsulation of the shop heads ?
Tom

Not encapsulating shop heads would violate all the industry standards (ex. SAE AIR4069). It is no doubt a contributor to overall failure rate, but not the problem. Consider blisters along the rear baffle line; shop heads are outside the tank.

[Rick6a]

Originally Posted by g zero

.......on the quick build tanks and others that you have seen with blisters are they lacking total encapsulation of the shop heads ?
Tom

Yes, blisters have been observed on quick build tanks that lack shop head encapsulation. It was the dozens of blisters on his quick built fuel tanks that prompted Dave Domeier to start this thread in the first place. One need only review the images in post #100 to confirm that shop head encapsulation was indeed omitted in the construction of those (not Dave's) quick built fuel tanks.

That said, a more in-depth review of this thread will reveal why blistering can occur along the rear baffle and virtually everywhere else for that matter if the fay seal is defective. A proper filet seal is highly recommended and industry accepted practice too.

[Martin Sutter]

My quickbuild RV7A has developed 6 separate leaks on rivets of the right tank. This is a 2005 vintage quickbuild. The leaks have all developed within the last year. All have been on the bottom ribs. Looking in the filler neck I can see that the shop heads of the rivets are only encapsulated on one side. It looks like they used an applicator and made one pass down the rib flange, leaving ample sealant on one side of the rivet (the front side in the direction of application) and a large void on the aft side. You can clearly see the shop head and the dimple is clear of any sealant on that side. I presume that was the mode of application used on all the ribs. Close inspection also shows tiny blisters on all bottom rivets of the tank, none so far on the top side. The aircraft has been in service since 2006 and has only been fueled with avgas.

Martin Sutter
Building and flying RV's since 1988
EAA Technical Counselor

[WildThing]

Originally Posted by DanH

http://www.vansaircraft.com/pdf/sb11-9-13.pdf

Thanks Dan. I guess I'll wait for Plan B - whenever that get's here. Or build a new set of tanks down the road if they get unsafe.

[JordanGrant]

Originally Posted by Stalldog

Jordan, where on the tank did the blisters appear, i.e. along the rib line or along the rear baffle, interior rib or exterior rib, etc.? So after six years blisters appeared at the same time on both tanks???

My blisters are all along the rib lines, in the front half of the tank. None along the rear baffle. Primarily on the bottom, although I have one on the top, near the leading edge. I might try the razor blade/heat gun repair technique on the bottom ones and see how it goes.

[Janekom]

About to paint a new RV10 and was wondering if someone has the document that Vans released some time ago on this issue. Thanks.

[jcbarker]

QB tanks 2003 vintage.
Professional paint 18 months ago.
One rivet leaked along rear flange. Fixed before paint. No problem
Blisters just showed. 5 on lower left. 1 on lower right.

Is Van's still silent on this issue?

[simatos]

Ouch this is not a discussion I wanted to join. I got these $#%^%$# blisters on my wings too, What the Heck??????!!!!!!!!!
Just noticed them. Quick Build 2007
painted one year ago
leak test no problems
Only on the tops, dark blue paint.

Am I looking and pulling of and resealing??????

G