Sealing a petrol tank

[Alpha22]

I'm looking for some kind of sealant that is 100% petrol proof for full time immersion. I have a tank that has an inspection hatch on the side. It is a large plate that bolts to a welded ring on the tank.

What magic gloop will provide a seal??

I've found "Sikaflex Tank N" but it's spec sheet only suggests it's good for 72 hours with gasoline.

There are various gloops available to restore fuel tanks.... but they are the "pour it in and spread it around" ... this is not an option, I can't invert the tank where it is.

Will fiberglass do it?? Will it stick to steel?

Any other ideas??????

 

[richardabeattie]

Gasket?

 

[macd]

There is almost no 'gloop' that will do what you want. Even specialist epoxies suffer some degredation from modern pump petrol, although it can be very slow. The same goes for fibreglass, even epoxy GRP. But all the treatments of which I'm aware require the tank to be rotated to spread the film, so no use in your case, anyway. I doubt you could lay up a satisfactory laminate through an inspection hatch with a tank in situ.

Your best means of investigating on-line may be motorcycle forums: GRP tanks were common on old bikes. Many surviving ones will have had epoxy treatment but now some of those are failing.

Can't you get the tank out?

 

[Alpha22]

Just to clarify the tank is mild steel....

I have found this.... PR-1770 Class B High Strength Fuel Tank Sealant

Which looks like it far exceeds exposure time..... apparently the RAF use it to seal inspection doors on aircraft...?

 

[macd]

Alpha, can you clarify:
is the leak from the inspection hatch seal or somewhere else on the tank? If it's the hatch seal, as richardbeattie wrote, it probably just needs a new gasket in something like nitrile rubber.

 

[Alpha22]

It is from the hatch seal....... I think some new gasket is in order..... but to prevent a re-occurrence - Id like to - Gloop it together with something. It's a big hatch...... way too big, but thats not something I can change.

Whats best for the gasket material....... nitrile rubber, cork, cornflake packet!!

 

[macd]

Whats best for the gasket material....... nitrile rubber, cork, cornflake packet!!

Suggest you Google gasket manufacturers for that information. Or read post #5.

 

[colind3782]

I have a roll of cork gasket from a previous life and I could send you a piece for the postage if you let me have the size you need.

 

[Alpha22]

I have a roll of cork gasket from a previous life and I could send you a piece for the postage if you let me have the size you need.

I'll measure it tonight.... thank you very much...

 

[lw395]

Ducati motorbike tanks have a big section in the bottom, where the pump and filter come out.
It's sealed by a Viton O ring.