A Genius Idea

Every time I am using a gasoline can to fill a mower, chainsaw, molotov cocktail, etc., I am annoyed by the safety mechanisms on the pouring spout.

I know the safety mechanisms are there for a purpose (safety!) but I also know that the real dangers with gas cans are when you take the spout off and fill the thing: if it falls over, or the guy at the pump next to you is smoking (this is Pennsylvania!) a cigarette, or something, you can be in the middle of your very own fuel/air bomb. The most important thing for gasoline safety is to get humanity to stop using the stuff. The second most important thing is to keep it enclosed, and it doesn’t matter what kind of pouring spout or can or whatever you use. In fact, I swear that I have spilled more gasoline dealing with safety pouring spouts than I would if the can just had a straight flexible spout.

search “gas can spout”

All of my various gas and kerosene cans have replacement pouring spouts that are the very simple kind with a screw cap and a flexible tube. No silly spill protectors; I’m not going to drop a can full of gas and stand there while it glugs out. You can buy replacement spouts for very little.

I admit I get a bit grumpy when I have to spend a cent to solve a problem that was caused by a solution to a problem I don’t think I have.

But, even the straightforward spouts have a problem: there’s no vacuum relief. As you pour from the can, the air in the can forms a vacuum and the pouring stops until the can “burps” or you burp it, or lower it so that it can breathe. That’s another way of spilling gas all over the place, thanks to the attempt to make gasoline cans safer.

I can’t tell you how many times I’ve stood there, waiting for the can to burp, thinking, “I wonder if there is some way to build a spout that has an anti-siphon in it? Sure there is – you’d need a tube coming alongside the gas, that carried air and exited above the level of the gasoline in the can. But I’ve never seen one of those. That doesn’t mean they don’t exist, it just means I’ve never seen one of those.

The other day, I got a small chainsaw (this is about the 5th chainsaw I’ve owned and this one is small so I can carry it in my truck) and that meant more gas-pouring and standing around fuming in the fumes. So I mentally bookmarked to get some replacement spouts and when I went to find them (at a certain huge online retailer that is gobbling the world) it offered me up, under “people who bought that often buy this” – air pressure relief valves. Holy crap what a great and obvious idea! I feel so stupid! Here I am, having this problem for decades, and someone solved it very simply a while ago. I guess I did not do my research. I have never seen that done before.

It’s a simple valveless valve body, with some O-rings and a washer and a nut. Getting it into the can was a bit of a trick – you drill the hole, then feed a wire through the hole until it comes out the pouring opening. (It helps if the can is empty while you are doing this, btw) (but if you are stubborn…) Then, you position the bottom half of the valve body on the wire and make a knob on the bottom of the wire so you can pull the threaded bit through the hole without having to fumble around trying to catch it.

There you go!

This is going to save me several minutes annually! I am not sure how to quantify any safety-loss in terms of risk. I don’t think my gas can is more dangerous.


  1. MattP (must mock his crappy brain) says

    Or just one of these with the relief valve already built into the thumb actuated pour/flow valve.

    Also saw something interesting while browsing last night: gas-station-style dispensing nozzle connected to a little push pump that replaces the gas can cap. Was all plastic with crap reviews, but the idea seems solid as it is basically just a hand-held/backpack sprayer that can fit on any gas can. Screw the cap on tight, give a few presses on the pump to add a bit of pressurized air into the can/tank, insert the dispenser nozzle into the device tank, and squeeze the grip valve on the dispenser to let the air push fuel up through the feeder tube in the can/tank out into the device tank.

  2. rojmiller says

    The US seems to have its own gas can designs. If you go to: Scepter Consumer Products, The US designs all all as you describe. Switch the Region to Canada/International, and the designs are mostly simple, with a flexible neck and back air relief valve. So all you need to do is cross the border to Canada when it reopens and stock up on gas cans! (Or get a friendly Canadian to ship you some?)

  3. says

    MattP (must mock his crappy brain)@#3:
    …and another stuck in the spam filter, I gues

    I don’t see anything pending. Lemme check. Maybe you posted a lot of links…

    Nope but I found it! Sorry about that. I see no reason that akismet thought that was spam. Maybe it just doesn’t like you specifically.

  4. James says

    So, I have to admit, I am a little confused…
    Every single gas can that I used growing up on a farm (in PA no less) and the two little ones I have today for a chainsaw and a weedwhacker… They all had / have small caps on the back side. You just open that up a bit before you pour and it lets air in as needed. Then when you are done you tighten the cap in the back, remove the cap / nozzle in the front, replace the seal that goes under them, then replace the cap / nozzle to hold the seal in.
    Do you mean to tell me that I have been extraordinarily lucky and most gas cans don’t have this?

  5. DrVanNostrand says

    I was just going to say that I agree with James, but I did a quick check on Amazon, and it seems that almost none of the gas cans have the little nubbin on the back to equalize the pressure. My only guess is that these fancy new spouts have the air valve built in, which makes the little nubbin on the can unnecessary. I haven’t ever actually bought a gas can myself, and all of the ones I’ve used have been pretty old, so I learned something new today. (For the same reason, I’ve also never had Marcus’s problem). So now I’m going to say I agree with Marcus. Why did they have to go and fuck up gas cans like this?

  6. johnson catman says

    I have two of the No-Spill 5-gallon containers that I bought from a local hardware store, not on Amazon, but here is the Amazon link so you can see what I am talking about: https://www.amazon.com/No-Spill-1450-5-Gallon-Poly-Compliant/dp/B000W9JN4S The nozzle is vented and has a thumb button to press to release the gas, and it stops immediately when you release the button. In addition, when your tank gets full and the end of the nozzle touches the liquid in the tank, it shuts off because it can’t draw air through the vented nozzle.

  7. Pierce R. Butler says

    Looks like a plastic gas can from here (not surprisingly, as the metal ones can generate sparks if scraped along pavement, and go BOOM).

    At least down south, however, those plastic cans face another hazard: the camphor shot borer, a tiny little beetle with a drinking problem. My last riding-mower fuel tank had to be scrapped because of over a dozen pinholes chewed in it by bugs with a craving for the ethanol they smelled in the gasoline; most of my gas cans are now useless too.

  8. johnson catman says

    re Pierce R. Butler @12: Alcoholic beetles? I haven’t had any problems so far (knock wood, har har), but I see that they are present in my state. I hope that the sealed nature of the jug won’t let the fumes out to attract them.

  9. DrVanNostrand says

    I just realized that Marcus basically just re-invented the 30 year old gas can. (I don’t know why, but I found this post very entertaining. It just keeps popping back into my head while I go through drudgery at work.)

  10. Lofty says

    I fixed the whole fuel leakage thing by going electric. Dewalt for one make ripper battery operated chainsaws and grass trimmers.

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