I just did this to my MacBook not because of the sharp edge but because the pitting turns a sharp edge into a sawblade. Something about the grounding on on the frame when plugged in mixed with my sweaty hands leads to damage along this sharp edge on every MacBook I've ever owned.

See https://www.reddit.com/r/macbook/s/hbyVh5SJhw for another poor soul with the same caustic skin

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CGamesPlay an hour ago | parent | next [-]

Oh is that why it happens? Was wondering why the spot directly under my wrist was pitted into a sawblade. I also filed it, though just enough to remove the pitting, nothing like the OP did.

It's easy for me to feel the mains frequency while gently rubbing the top surface of the MacBook while it's plugged in. Really feels unsafe, but neither me nor the computer have suffered any serious injuries yet.

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normie3000 14 minutes ago | parent | next [-]

> It's easy for me to feel the mains frequency while gently rubbing the top surface of the MacBook

I haven't been a regular Mac user, but I've had maybe 3 work MacBooks since 2010 and I recall having this issue with all of them.

Why haven't they fixed it?

	▲	msephton 10 minutes ago \| parent [-]
		It's also an issue on the new Neo. It was the first thing I noticed when I tried one in the Apple Store. I unplugged the power cable and it went away, replugged and it came back. I'm in the UK so I expected grounded electricity supply.

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ajam1507 an hour ago | parent | prev [-]

Using a 3 prong extension cable on the charger will prevent this.

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imglorp an hour ago | parent [-]

How? The (US) charger's only got 2 pins so ground stays unconnected.

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pxx 29 minutes ago | parent | next [-]

There are grounded duckheads for this purpose, e.g. https://amzn.to/4cnzuef (note out of stock. I guess your best bet is to use a UK duckhead, but half of those have a dummy ground...)

if you take the plug part from the brick you'll note that there's only two pins but the button-like thing is a ground

as noted in a sibling, the power adapter extension cable does plumb the ground through (https://www.apple.com/shop/product/mw2n3ll/a/power-adapter-e...)

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bombcar 31 minutes ago | parent | prev | next [-]

I don't know if this link will work - https://www.chargerlab.com/wp-content/uploads/2022/06/202206... but that metal round pin thing is a ground; and the three-prong cable connects to it.

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Tsiklon 37 minutes ago | parent | prev [-]

The extension cable they used to include in box with the computers, it has the third pin for the charger brick connector which is wired to ground

	▲	15155 10 minutes ago \| parent [-]
		There's zero chance that the DC ground in the laptop is tied to earth ground in the charger: they use LLC resonant converters and flyback converters (depending on vintage) - an earth ground tie would defeat the purpose of these isolated topologies.

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al_borland 2 hours ago | parent | prev | next [-]

This comment is concerning.

> acidic sweat. once you got through the anodization the raw aluminum wears faster....

If one files off the sharp edges, won’t the sweat eat through everything faster, as that protective layer was filed off.

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crdrost an hour ago | parent | next [-]

Probably. But, the time when the laptop is taped off would be uniquely a good time to hit it with some polyurethane or something clear to protect it from that sort of damage? Just make sure you hit it with compressed air first so you aren't gluing the aluminum dust to the chassis?

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compass_copium 2 hours ago | parent | prev [-]

Aluminum should oxidize essentially instantly.

	▲	lukevp 2 hours ago \| parent \| next [-]
		Anodizing and oxidation are 2 totally different things.
	▲	themafia an hour ago \| parent \| prev [-]
		True; however, this is an aluminium alloy. These typically have lower corrosion resistance and are most commonly anodized because of it. The applied layer is typically 3 to 5x thicker than that formed by pure aluminium oxidization.

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dataviz1000 an hour ago | parent | prev | next [-]

I’ve been traveling around the world. It is 50 / 50 of the socket is properly grounded —-anywhere in the world. I get a tingling zap on the wrist when not properly grounded. The charger also gets hot and sparks.

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ddlsmurf 31 minutes ago | parent | next [-]

but it's never going to be grounded, there isn't even a ground pin on the charger

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russelg 12 minutes ago | parent [-]

If you swap in the extension cable head, that does indeed have a ground pin, at least in Australia anyway. The grounding comes from that metal ring that the connector uses as a guide. https://www.apple.com/au/shop/product/mw2n3x/a/power-adapter...

	▲	ddlsmurf 9 minutes ago \| parent [-]
		only two prongs of which make it through. Usually the regulation as I understand is that it's fine if you can prove the case can never get in contact with anything electric, for most laptops that's just being made of plastic.

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shawn_w 23 minutes ago | parent | prev [-]

>The charger also gets hot and sparks.

Some heat is normal, but the sparking seems concerning.

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greazy 2 hours ago | parent | prev [-]

Oh wow I think I have a mild version of this.

Can it cause the plastic on the mouse to break down?

	▲	bluGill an hour ago \| parent \| next [-]
		Yes, it is fairly common with some plastics. better plastics won't but there are a lot of different plastics with differt formulas (and many can be mixed)
	▲	BoredPositron an hour ago \| parent \| prev [-]
		You need to moisturize more.