…it seems wasteful to toss a whole can over a 3 ounce cap… Then it dawned on me I’m a big bad 3d printing homesteader nerd!
Did it work out? Hell yes it did!
Most of my cans are “Wedco”. There are other brands. Also, if your fuel can isn’t filthy you haven’t been using it enough.

I don’t know where I picked it up but the slang term for the spout is “donkey dick”. I will always refer to it as such. I’m not allowed in public for such reasons.
This is a second generation donkey dick. Meaning the first one wore out a long time ago and this is an “aftermarket replacement”. It is also worn out, it leaks all over the place! [Insert inappropriate joke here.]

Here’s a replacement printed in Bambulab PETG-Translucent. There’s no reason why you should choose translucent but there’s no reason why you should not.

Note: I did not design this. I downloaded it off Printables.com. Here’s the link. The guy who made it did a good job I think. It’s on a wide open creative commons license.
This particular donkey d… spout… is meant for ventless post-California enshittified design gas cans. It has an internal vent and there’s an adjunct air tube that goes into the can. You can see it as a little worm sized thing on the print bed. The internal vent arrangement is more complex than necessary but I don’t think that’ll make it pour worse. I made my first print using the standard model rather than tweak it. If it’s not exactly what I want, I can always take out that bit and/or just make my own design.
A note about vents:
Every red blooded American either has pre-Enshittified cans (like I do), has manfully drilled a vent hole in their enshittified can, or has bought a “water” can that they use for gas. The latter option is what I call “Soviet workaround”; even in the most totalitarian situations “loopholes” appear. They’re tolerated because sometimes you simply have to get shit done. That’s why Amazon and others used to list a variety of “water cans” that look exactly like they’d be perfect to fill your (non-electric) lawnmower.
Another workaround are little “vent kits” that you can get on Amazon and other places. They’re specifically made so you, the homeowner, can drill into an enshittified gas can and “convert” it into a useable gas can. If it freaks you out that there’s a kit to do exactly what the factory isn’t allowed to do, wait ’till you hear how they sell 30 round mags in Colorado.
But I digress. I’m not sure the California can is still law of the land. I no longer care. I just don’t buy new cans because I don’t need to fund stupidity. I’ve basically left the market; possibly for life. (I suspect Ayn Rand would take that last statement and turn it into a 50 page monologue.)
The donk…… spout is held on by a “nut”. (Don’t blame me for what you’re thinking, I didn’t name these things. The dirty jokes are pitched across the plate!) I downloaded a model for “nut”… ugh this is killing me.
The nut printed out great but didn’t match the thread on my jugs. (That still sounds dirty!)
The silliest, crudest, most improbable solution I could think of was to rescale and print a larger nut. I scaled to 105% and it fits the threads flawlessly. I can’t believe that worked!
For some reason I took no photos. I also forgot to preserve the link. You can find it with a quick search on Printables.
When you remove the d…… spout, you need an insert to block the hole in the nut. It’s at this link. I scaled it at 105% to match the larger nut and it fit perfectly.
I took the gasket off my old… spout. And put it on the new… spout. A gasket makes the seal a lot better.
I wanted a gasket on the insert. There were comments that this one was a finicky print. People complained it was too small. (Dammit why is everything a setup to a punchline?) The link is here. The commons license says no sharing without attribution. Since I’m not sharing the file I’m still within the license. Also it’s just a disk, you could design your own in a few minutes.
I printed a series of gaskets, inflating about 1% between each one. Then I selected the best fit. It worked great. Calibration is science!
Gaskets should be made of “squishy” material. I used Bambulab TPU 95A HF. It’s good with solvents and it only took about $0.11 to make a plate with every possible size.

Real gas cans have a vent. This is the vent cap file I found at Printables. It worked fine with no need for scaling.

I find it absolutely bizarre that they even made unvented gas cans. It’s such a weirdly Utopian madness… but it happened.

Here’s a few gas cans. Some cans have newly 3d printed bits. Some remaining bits are still useable and don’t need replacing. Others bits are crappy and are waiting while I count and print more pieces to swap in.
It’s also a cameo by our elderly barn cat.

None of this is rocket science, but it’s proof of concept. I needed a thing and within a day had printed precisely what I wanted. I can print essentially infinite numbers of those items and they don’t use much filament so they’re dirt cheap. How cool is that?
Another 3d printing happy moment.
I was out trimming branches with what I call “chainsaw on a stick”. I didn’t notice at first but I was using a battery that had been damaged but then I fixed it with 3d printing.
I did that about a year ago. The OEM housing cracked, I replaced it with a knockoff housing that lasted about a year but then it too cracked. I printed a new housing (choosing red and black colors probably at random) and it’s holding together fine. (I also swapped the batteries and electronic gadgetry.)
It worked so well that I didn’t even notice it at first. It looks, works, and feels as good as the OEM stuff. How cool is that?
