S

Squeak

Well Known Member
I really took my time building the fuel tanks to make sure not to have a leak. I finished my last fuel tank and tested it today and found a leak in the middle rib and the very last bottom nose rivet. Should I drill out and cut a hole in the baffle plate and buck a new rivet or is there a blind rivet I should use? It is in the bottom last nose rivet and its going to be a bear. Any links or ideas for the repair will be appreciated.
Squeak
RV-7A
 
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Have you tried the self-wicking Loctite? I think it's loctite 290. That's what Van's recommends in their tank test kit instructions and other builders have recommended. I wouldn't cut a hole in your baffle until you've tried that.

Good luck.
 
Steve, I remember reading that on Van?s web site but could not find it. I believe you just put the loctite on the rivet head and let it dry over night. I will look again for the loctite numbers and try that before cutting a hole.

After looking at the rivet more I noticed it was not flush as the rest of the rivets so I tried to move it around and found out I did not buck that rivet. What a careless mistake. I have done all my riveting by myself so I cannot blame this on anyone but me. So my question is now with the rivet removed from the tank skin can I use a blind rivet. What # rivet?

I clean it up good and used a lot of proseal on a MK-319-BS blind rivet. I will test again tomorrow. Build ON!!


Squeak
 
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It is indeed Loctite 290. I found it at McMaster-Carr. I was skeptical, but the stuff worked perfectly on my slowly weeping rivet. I just put it on the rivet head, and it wicked in. At least it stopped the air leak--I haven't put fuel in the tank yet.

Dave
 
blind rivet and proseal

I didn't have much luck with loctite on any of the several weeping rivets on the bottom of my tanks.

Best, and easiest solution is to drill out the rivet, then a couple of turns with a deburring bit to smooth out the dimple, then use an MK-319-BS rivet coated in proseal to seal it up.

You can fix this in about 10 minutes.

-Clay
 
The MK-319-BS blind rivet and proseal worked no more leak. I used the deburring bit to smooth out the dimple also. I used Van's test kit and the colored water stay right on the line for 14 Hours. I am so glad to be done with the tanks they are both mounted on the wings.
Squeak
 
Do it right the first time

You have spent lots of time building the fuel tanks so fix it the correct way. Do you really want to trust locktite for years to come. Cut a hole in the rear baffle and slop some more proseal on the inside of the leaking area. Proseal and blind rivet a plate over the hole in the baffle and your done. Use the same blind rivets that are called out on the plans for the rear baffle.

We just repaired a leak in the left tank of a 6 and it took 2 hours, from tank pull to reinstalling the tank. We let the proseal cure for 3 days and went flying. And no more leaks.

I used the faster curing proseal that Van's sells for the trailing edges of the new style control surfaces.

Gary
 
Obviously the thin skin of the tank cannot stand much differential pressure, so any method you can think of to generate the vacuum has to have deliberate and failsafe pressure limitations.

You can create a valved setup that uses your home vacuum to create the low pressure and include a tee in the line that has a transparent tube with the end submerged in a jug of water.
turn on the vacuum and then open the valve to the tank. You can observe vacuum by the number of inches the water is drawn up into the transparent tube. (I would try to stay below 5 inches water column).
You could design the system so that when some vacuum level was exceeded, the tube end would uncover and prevent any further increase in the vacuum.

In other words, it is very easy to damage your tank with too much vacuum.

Be careful!

-mike
 
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