Fuel Tank Weep

[skippydiesel]

My aircraft uses a composite fuel tank.

 

I burn 95/98 RON very very  rarely AvGas 

 

At the top of the tank there is a circular metal plate that houses/contains the fuel gauge sender mechanism, and the three fuel pipes (Main, Aux & Return).

 

The plate is secured by many screws. I assume (never dismantled it) that  it is a "sandwich" type securing sealing system, utilizing a  gasket and/or sealing compound.

 

Recently I have noticed that this structure has developed a small fuell weep, with a brown sticky stuff oozing from the area that is weeping.

 

I would like to effect a good repair.

 

All suggestions welcome, with particular advise regarding suitable fuel resistant sealing compounds.

 

 

[M61A1]

PR1776 is a good fuel tank sealant, but it sounds like you should make a new gasket. Viton sheet is available in 1.6mm.

 

 

[skippydiesel]

Thanks M61A1 - checked out your suggestions. I have no doubt that they would do the job very well BUT the cost $$$$$.

 

I would need to measure the plate but my estimate is its about a 100mm diam circle - I would hope for a much less costly solution.

 

 

[Downunder]

I helped repair a leak in a top inspection hole on a wing.

 

It had a cork gasket. We cleaned it well with acetone an applied a sealant from an automotive store.

 

It was called "something" putty. I was worried it was going to be thick like muffler putty but was more like thick silicone. Worked well.

 

I'll try and find full name.

 

"Downunder, from rainy Tassie!"

 

 

[nomadpete]

Do you mean to say that you are down under downunder.........?

 

 

[Downunder]

Yes....first time! Rosebery....arrived Devonport today on Qantas. All free for work...

 

Last Monday I was at Mt Augustus....middle of WA.(on my own dollar) 

 

Bit of a difference...

 

 

[Marty_d]

I bought some rubberized cork gasket material (1.5mm) to use as a cushion / anti-rub separator between the oil tank and the bracket it sits on.  Cost me about $20 for a roll of it, certainly enough to get a few 100mm circles out of.  As far as I know it's fuel/oil resistant.  Got it from a local engineering place.

 

Ring around - someone will have a solution.

 

 

[onetrack]

This stuff is the answer to any oil or fuel leak, in anything mechanical. Been around for yonks, still can't beat it.

 

https://www.permatex.com/products/gasketing/gasket-sealants/permatex-form-a-gasket-no-2-sealant/

 

 

[skippydiesel]

This stuff is the answer to any oil or fuel leak, in anything mechanical. Been around for yonks, still can't beat it.

 

https://www.permatex.com/products/gasketing/gasket-sealants/permatex-form-a-gasket-no-2-sealant/

 

That's my man! - about $12  - even I can afford that and I probably already have some cork gasket sheeting lying around that might make a new gasket.

 

 

[facthunter]

I've gone onto better for engine crankcases which are accurately machined surfaces. I'd rely on a neoprene gasket preferably without any sealant on that situation. Nev

 

 

[kgwilson]

Permatex is indeed a great fuel resistant sealant. I used it on all of the threads etc in fuel line nipples from fuel pumps and I have never had a problem. Without it even though the brass fittings have tapered threads they leaked.

 

 

[onetrack]

Skippy, some composite gasket material (nitrile bonded, rubberised cork) could be a better choice than just plain cork gasket.

 

Plain cork is good for vibration and noise reduction, but the composite of cork and nitrile rubber is particularly good at stopping weeps.