Tank leak fix?

[Hercpilot]

While pressure testing the fuel tanks on my varieze, I discovered a leak around the vent lines just as they enter the fuselage side going into the tanks. Any suggestions on how to fix this problem other than the obvious of removing and replacing.

 

P.S. The lines where in when I purchased the project.

 

Justin

[MikeD]

Justin,

 

The fix in the Long-EZ plans indicate the easiest way is to identify the leak area, apply a slight vacuum to the system then cover leak with resin. The vacuum will suck the resin into the leaking area so I would assume you have to release the vacuum reasonably quickly before ALL the resin has been sucked in. Allow to cure and repeat the procedure until the leak has been sealed.

 

MikeD (U.K.)

[argoldman]

Justin,

 

The fix in the Long-EZ plans indicate the easiest way is to identify the leak area, apply a slight vacuum to the system then cover leak with resin. The vacuum will suck the resin into the leaking area so I would assume you have to release the vacuum reasonably quickly before ALL the resin has been sucked in. Allow to cure and repeat the procedure until the leak has been sealed.

 

MikeD (U.K.)

Although that technique works well for distant leaks, it is a balancing act.

 

If you suck too much, you will get resin into the tank and it will not seal. If you suck too little, you will possibly plug up the site that the fuel is leaking to the outside, but the leak in the tank is still there and it will with time find it's way outside again. However, without major dismantling, that may be the only option, for distant leaks.

 

However, in this case, it seems obvious (?) that the leak is coming from the epoxy/aluminum (aluminium) tube juncture.

 

If it is accessible then, without chewing the aluminum excessively (at all), using a Dremel, grind the flox, micro, etc which is on the outside of the tank, around the tube, back until you have removed it and can visualize the inside skin of the tank (that that the fuel touches) Roughen this surface, and that of the tube. Use flox (starting with a relative wet layer at the skin, getting a little drier as you go out) and fill the defect with a little extra to create a mound surrounding the tube. Of course wet the whole thing with raw epoxy first. If you want to, put a layer or two of Bid over this, extending about 1" onto the prepared surfaces adjacent to your surgery. I would use about a 1" dia cutout around the tube.

 

Good luck

 

Rich

[RGlos]

I agree with AR on this one.

 

This is the exact method I have used in the past. Especially when I installed a new pair of Atkinsons fuel site Gages.

 

The only thing I can advise is to keep the flox mixture on the wet side, even if you have to hold in position with duct tape.

[steve]

Although that technique works well for distant leaks, it is a balancing act.

 

If you suck too much, you will get resin into the tank and it will not seal. If you suck too little, you will possibly plug up the site that the fuel is leaking to the outside, but the leak in the tank is still there and it will with time find it's way outside again. However, without major dismantling, that may be the only option, for distant leaks.

 

However, in this case, it seems obvious (?) that the leak is coming from the epoxy/aluminum (aluminium) tube juncture.

 

If it is accessible then, without chewing the aluminum excessively (at all), using a Dremel, grind the flox, micro, etc which is on the outside of the tank, around the tube, back until you have removed it and can visualize the inside skin of the tank (that that the fuel touches) Roughen this surface, and that of the tube. Use flox (starting with a relative wet layer at the skin, getting a little drier as you go out) and fill the defect with a little extra to create a mound surrounding the tube. Of course wet the whole thing with raw epoxy first. If you want to, put a layer or two of Bid over this, extending about 1" onto the prepared surfaces adjacent to your surgery. I would use about a 1" dia cutout around the tube.

Good luck

 

Rich

ar is spot on this time (and the last time) and if i was you (him) id do it as he so wonderfully spelled out >AR not ar....sorry;)