Busted: Toilet Paper As Solder Wick

It didn’t take long for us to get an answer to the question nobody was asking: Can you use toilet paper as solder wick? And unsurprisingly, the answer is a resounding “No.”

Confused? If so, you probably missed our article a few days ago describing the repair of corroded card edge connectors with a bit of homebrew HASL. Granted, the process wasn’t exactly hot air solder leveling, at least not the way PCB fabs do it to protect exposed copper traces. It was more of an en masse tinning process, for which [Adrian] used a fair amount of desoldering wick to pull excess solder off the pins.

During that restoration, [Adrian] mentioned hearing that common toilet paper could be used as a cheap substitute for desoldering wick. We were skeptical but passed along the tip hoping someone would comment on it. Enter [KDawg], who took up the challenge and gave it a whirl. The video below shows attempts to tin a few pins on a similar card-edge connector and remove the excess with toilet paper. The tests are done using 63:37 lead-tin solder, plus and minus flux, and using Great Value TP in more or less the same manner you’d use desoldering braid. The results are pretty much what you’d expect, with charred toilet paper and no appreciable solder removal. The closest it comes to working is when the TP sucks up the melted flux. Stay tuned for the bonus positive control footage at the end, though; watching that legit Chemtronics braid do its thing is oddly satisfying.

So, unless there’s some trick to it, [KDawg] seems to have busted this myth. If anyone else wants to give it a try, we’ll be happy to cover it.

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Disposable Diapers Are A Tribute To Material Science

It’s a really tough problem that has been solved to an amazing level. How do you capture and contain urine from a floppy, curved, and moving human infant? Ah, but the problem is a bit harder than that. You also want to keep that liquid away from the soft skin of the newborn and keep the exterior of your overall system dry too. From an R&D point of view the nice thing is that the customer base is huge — everyone needs some type of diapers. And what we have achieved thus far is a huge accomplishment of material science. [Bill Hammack], The Engineer Guy, takes on the engineering of baby diapers in his latest video.

A diaper uses three inner layers to sweep urine away from baby’s skin. The first layer actually repels water — being injected between skin and this layer, liquid passes through the holes in the material. But the moisture repellent property prevents it from moving in the opposite direction because of the next two layers encountered. The second layer uses capillary action to pull the moisture toward the third (and to act as a one-way moisture valve). The third layer contains a super-absorbent polymer. That layer starts off very thin and swells with absorption.

Bill explores just a bit about how these materials are actually manufactured. The layers are non-woven to form the necessary structures. The absorption layer uses cotton fibers to ensure moisture doesn’t form a dam between polymers. Whether you have a little one in your own household or not, the science behind this solved problem is fascinating and well worth the six minutes you’ll spend on the video below.

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