To Fix a Tank leaking

[deesaysy]

Hello

I have a slow tank leak that is emerging from the bottom corner where

the spar and strak meet.

I came across Kevins Walsh fix that he posted in response to Cambells

posting of "fuel tank" (topic# 108413). Unfortunately, I had several questions.

Also, I was looking for some guidance here.

First question, would you change or handle the leak any differently from what you did

to fix your plane (having had a year to further think on it).

Question 2: when you fixed your 10" square hole, could you tell me how you did it.

Did you re-install the foam? how did you glass the inside of the patch to seal it?

 

Question 3: Is it possible to instead of making a 10" square incision. Just Widen the 

gas cap enough that you could stick your hand in the tank to do the repair and be able to see

inside it. Are there bigger fuel caps?

 

 

 

Edited December 21, 2021 by deesaysy

[Kent Ashton]

9 hours ago, deesaysy said:

Hello

I have a slow tank leak that is emerging from the bottom corner where

the spar and strak meet.

I came across Kevins Walsh fix that he posted in response to Cambells

posting of "fuel tank" (topic# 108413). Unfortunately, I had several questions.

Also, I was looking for some guidance here.

First question, would you change or handle the leak any differently from what you did

to fix your plane (having had a year to further think on it).

Question 2: when you fixed your 10" square hole, could you tell me how you did it.

Did you re-install the foam? how did you glass the inside of the patch to seal it?

 

Question 3: Is it possible to instead of making a 10" square incision. Just Widen the 

gas cap enough that you could stick your hand in the tank to do the repair and be able to see

inside it. Are there bigger fuel caps?

 

Kevin's last post here was in 2010.  You might reach him with a PM.  If not I believe he is active in the Cozybuilders Google Group.  Or just use google to find him.     https://www.canardzone.com/profile/126997-krwalsh/?wr=eyJhcHAiOiJmb3J1bXMiLCJtb2R1bGUiOiJmb3J1bXMtY29tbWVudCIsImlkXzEiOjIwMzYyLCJpZF8yIjo0Njk0MH0=

The first thing I would try is pressurize the tank to about 21" of water differential with the tank nearly empty and airplane on the nose, and see where the leak is showing up.  Then I might draw a mild vacuum on the tank and paint warm epoxy over the leak area.  If no workie, I might empty the tank, ventilate it well to evaporate the avgas (maybe with nitrogen--I don't know) and try to direct some raw epoxy into the interior corners with a borescope and whatever you can manage.  I have seen pics of people hanging an EZ to get raw epoxy where they wanted it.

I would not consider it a big deal to cut open a tank.  Leave an interior edge to support new foam,  glass one side of the new foam and glue it in the hole using plenty of wet flox, Glass over the patch with two BID.  Be sure to clean the tank thoroughly before closing up the hole and check the gascolator screen and filters often in the first few hours.

Edited December 21, 2021 by Kent Ashton

[A Bruce Hughes]

If you plan to cut the tank open study the plans very carefully first.   You will have three areas on each tank to consider.  It is not an easy job and you may create more leaks.   You also may leave small bits of foam or other material; you cannot vacuum those out due to the internal baffles and they may later plug a fuel line.   Get help from an experienced builder.

[deesaysy]

12 hours ago, deesaysy said:

Hello

I have a slow tank leak that is emerging from the bottom corner where

the spar and strak meet.

I came across Kevins Walsh fix that he posted in response to Cambells

posting of "fuel tank" (topic# 108413). Unfortunately, I had several questions.

Also, I was looking for some guidance here.

First question, would you change or handle the leak any differently from what you did

to fix your plane (having had a year to further think on it).

Question 2: when you fixed your 10" square hole, could you tell me how you did it.

Did you re-install the foam? how did you glass the inside of the patch to seal it?

 

Question 3: Is it possible to instead of making a 10" square incision. Just Widen the 

gas cap enough that you could stick your hand in the tank to do the repair and be able to see

inside it. Are there bigger fuel caps?

 

Re: Fuel Tank

Kevin R. Walsh 8/24/20   #108414         On Mon, Aug 24, 2020 at 8:21 AM Steve Campbell via groups.io <campb001=umn.edu@groups.io> wrote: I am finishing up phase one testing and I find that I get a dripping leak from one of the tanks if I fill it more than 3/4 full. Aircraft Spruce sells this stuff https://www.aircraftspruce.com/catalog/appages/gastanksealer.php   to solve this kind of problem. Of course, I am extremely leery of putting anything in the tank that could delaminate and clog the fuel system. Anyone have any experience with it in a Cozy/Long/Vari? One of the questions on Spruce's web site was:   _._,_._,   I had a problem on my right tank where when the tank was completely full, in a climb, it would wick from the strake to fuselage seam at the top, through the foam to a 1/8" diameter channel that I had put through to run the coax for my fuel level sensor, then into the rear cockpit as a drip-drip-drip.   I would suggest that there is no magical cure here.  You need to find the leak and properly patch it with EZ87 or whatever epoxy you used for your tanks.  In my case I ended up cutting a ~10" square hole in the strake top to access the corner, which had been insufficiently smeared with wet flox when originally.  I sanded down that intersection and put a nice EZ87 and flox fillet in there, and it has been perfect since then.       -- Kevin