Petrol-proof washer

[PeterC]

The 'can' for spare petrol (lawnmower - and neighbour's for her car) has a washer in the cap but not in the long nozzle. Of course, the petrol dribbles out which, with a hot motor on a hot day... I have some washers that fit (Aldidl kit) but they shrink and deform after a few weeks. They're about 39 mm (1.5") OD and 30 mm ID. I've tried Halfwits (I was up that way, OK?) and don't know where else to go. Looking at such cans in Wickes showed that even new ones don't have washers! Any pointers please?

[Mentalguy2k8]

Buy a new can which doesn't leak? They're only a few quid.

[newshound]

Probably because it is the cheapest type of rubber (SBR). Get Nitrile rubber sheet from eBay, cut a new one. Of course in hot weather the can is going to pressurise itself, so it may not seal if the washer is below the level of the liquid.

[The Natural Philosopher]

try making one out of silicone sealer. apply a bead around the nozzle top, and then screw it down and leave it. wIth luck the nozzle will unscrew.

Or better still, buy a funnel and throw the bloody nozzle away. They are as you have discovered almost useless.

[PeterC]

The can's OK as is the cap. As new cans will have the same problem it seems pointless repeating the process.

[PeterC]

Ah, thanks - it was nitrile that I couldn't remember. I'd guessed that the washer was butyl. If the washer is below the liquid, it means that the can isn't upright. With the nozzle on, the can's not pressurised.

[PeterC]

OK, I'll give it a go.

The nozzle actually works very well and means less stuff to lose, as it fits around the can when not in use.

[Adrian]

Will just harmlessly evaporate.

[Tim+]

Um, surely you've got the cap on when it's not in use? You'd only you the nozzle outside the car. Minor dribbles will evaporate away outside quickly enough. Or have I not understood the problem?

Tim

[Dave Plowman (News)]

Before synthetics, those brown/red fibre washers seemed to be used on car carburettors.

[Grimly Curmudgeon]

Silicone sealer falls apart when petrol touches it.

[Grimly Curmudgeon]

Don't waste your time. TNP issues such advice and has no fecking clue.

[The Natural Philosopher]

I said try.

I have never seen silicone fail on contact with petrol

[Fredxx]

That's not my experience. What sealant did you use?

[PeterC]

Yes, of course. The whole point of this is that the nozzle dribbles around the thread when filling mower or car. The petrol seems quite good at killing grass (perhaps would be better with vinegar/salt in it) and moving off the grass almost always means being close to buildings.

[PeterC]

Too hard for plastic threads - useless on shower hoses as well.

[Dave Plowman (News)]

If the plastic is that soft it should deform enough to provide its own seal. Have you checked for moulding ridges etc which if removed would allow this?

[Grimly Curmudgeon]

I have; more than once.

[Grimly Curmudgeon]

Automotive gasket silicone, not some bathroom stuff.

[F Murtz]

Petrol eats silicone, don't use silicone any where near petrol