Samsung's Galaxy Z Flip isn't officially dust-proof, but Samsung took some measures to make it harder for dust to penetrate into the device, including placing little dust-repelling brushes into the hinge.

But the brushes don't do a particularly good job of stopping dust from entering the device, at least according to the experts at iFixit, who tore the phone down to bits and tested its dust-repelling properties.

To do this, iFixit used a simple experiment: They placed the phone into a bag together with a bunch of easy-to-spot purple dust, and shook the bag for a few seconds. If the dust entered the phone, it would be visible once it was opened, and sure enough – there it was, in copious amounts.

Even worse, immediately after the test, the Z Flip's hinge made an odd, cracking sound when the phone was opened, and was pretty much unusable. Ouch.

The folks at iFixit warn that their test goes "well above and beyond normal working conditions," but it's still not very comforting to see dust penetrating the phone that easily.

The rest of the teardown, available here, is an interesting read as well. Highlights include two distinct battery cells with respective capacities of 2,370mAh and 930mAh, the ultra-thin glass in the display which iFixit says is actual glass, but under a layer of plastic, and a poor repairability score of 2 out of 10.