More fun with Jerry can vents

Yesterday I managed to dribble gasoline all over the back of Landlady’s Prius, as 2 of 3 retrofitted Jerry can vents decided to leak precious juice.

I assumed the same thing happened as before, that the sealant held but the cans’ paint gave way. In fact, not so much.

vent1
The plan called for sanding down the area around the vent hole, so I did that despite the lack of any serious evidence of flaking paint.

vent2
This one clearly shows that the sealant just got hard and cracky, and broke free of the vent without ever pulling the paint off the can. I’m confused by this, since the cans are not left out in the sun. I put a cover on the trashcan corral specifically to get them out of the sun. So now I’m starting to think I need to find a better sealant, though in every other way this stuff has always worked fine for me.
vent3
Anyway, they’re all fixed again. So we’ll give it another try. So far I’d have to say that if you want metal rather than plastic fuel cans, you’ll have to spend the money for milspec. These are full of trouble.

Next time – and there’s sure to be a next time – I’m going to take somebody’s advice and replace the current vent with a tire valve just to see if that’ll seal better.

About Joel

You shouldn't ask these questions of a paranoid recluse, you know.
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7 Responses to More fun with Jerry can vents

  1. Ben says:

    First guess would be that your goup doesn’t like gas fumes, but who knows? It’s convenient that you didn’t blow up Landlady’s Prius.. the valve core idea seems well worth a try.

  2. Unclezip says:

    Huh. I thought the only reason for a gasoline/Prius mix would be a bonfire.

  3. Joel says:

    Naw, it’s cool. Hybrids are proven useful in their proper environment. The Prius was never meant to go off-road – it’s designed for reduced drag coefficient and rolling resistance and will ground out on small rocks off-pavement. But if I lived in a town I’d sure love that gas mileage, to say nothing of the quiet.

  4. doubletrouble says:

    The valve stem works well, but the hole in the can should be very close to the minor diameter on the stem. Since you already have the hole, unless you’re lucky you may have to search for a larger (truck) sized stem. Alternatively, automotive RTV comes in various incarnations, some of which are resistant to gasoline.

  5. Ben says:

    On second thought. I just read somewhere on the Interwebs that if you drop a rubber tire valve stem in a cup of gasoline overnight (as a simple experiment), you may decide that they wouldn’t make a good gas can part. Disclaimer: I haven’t tried this for myself.

  6. Mike says:

    Joel i would be careful using a tire valve because of the issue with rubber and gasoline. It looks like there could be a serious compatibility issue with the rubber and the gasoline which will cause the rubber component of the valve stem to fail.

    If you click on the link I’ve provided and look at this chart on the left there is a list you can scroll down to gasoline. Then on the right click on natural rubber this will tell you about any compatibility problems.

    http://www.applerubber.com/chemical-compatibility-guide/

  7. DOM says:

    If you use some aircraft fuel tank sealant (known colloquially as “PRC”) you’ll have better success. It isn’t cheap though
    https://m.skygeek.com/prc-desoto-pr-1422-courtaulda-sealant.html
    I’ll keep my eyes peeled for some “expired ” stuff at work.

To the stake with the heretic!