As we’ve said many times in the past, the creation of custom cases and enclosures is one of the best and most obvious applications for desktop 3D printing. When armed with even an entry-level printer, your projects will never again have to suffer through the indignity of getting hot glued into a nondescript plastic box. But if you’re printing with basic PLA, you need to be careful that nothing gets too hot inside.

Which was a problem when [Oleg Vint] started work on this 3D printed case for the popular TS100 soldering iron. But with the addition of a standard 608 bearing, the case provides a safe spot for the iron to cool off before it gets buttoned back up for storage. Of course, you can also use the flip-out perch to hold the iron while you’re working.

As [Oleg] explains on the Thingiverse page for the case, he actually blended a few existing projects together to arrive at the final design. Specifically, the idea of using the 608 bearing came from a printable TS100 stand originally designed in 2017 by [MightyNozzle]. Released under Creative Commons, [Oleg] was able to mash the bearing stand together with elements from several other printable TS100 cases to come up with his unique combined solution.

via Printed TS100 Case Beats the Heat with a Bearing — Hackaday

Solder is the conductive metal glue that one uses to stick components together. If you get the component and the PCB hot enough, and melt a little solder in the joint, it will stay put and conduct reliably. But it’s far from simple.

There are many different solder alloys, and even the tip of the soldering iron itself is a multi-material masterpiece. In this article, we’ll take a look at the metallurgy behind soldering, and you’ll see why soldering tip maintenance, and regular replacement, is a good idea. Naturally, we’ll also touch upon the role that lead plays in solder alloys, and what the effect is of replacing it with other metals when going lead-free. What are you soldering with?

Intermetallic Compounds

Soldering, and its higher temperature cousin, brazing, are one of essentially two ways create metal-to-metal bonds, and they allow the use of low-temperature techniques that still create relatively stable bonds between two metal surfaces. Soldering is also an interesting chapter in the field of metallurgy, on account of it being based around so-called intermetallic compounds (IMCs).

Welding stands in contrast to soldering, where high temperatures melt the metal on both sides of the pieces that are being joined, permanently fusing them. Welding is a high-strength, high-reliability way of joining metal pieces, but is unfortunately wholly unsuited for delicate electronics where excess heat can damage parts and the goal is more to ‘glue’ electrically conducting elements together than to melt them together.

This also leads us to the reason why soldering and IMCs are such a source of trouble, to the point where IMCs are referred to as ‘evil’. IMCs are essentially bits of the two metal surfaces on either side dissolved into the solder, causing enough of a joining that each side of the joint is more or less stably fused with the solder. Unfortunately such an IMC is a far cry from the stable solid metal of a welding joint, and as a result can be brittle depending on exactly which metals were involved in the solder alloy.

But the IMCs formed in soldering are strong enough, and their formation is at the root of why every solder alloy uses tin. Tin has the property that it is very good at letting other metals dissolve into it. In fact, it’s possible to solder with pure tin, although as we’ll see below, most solder is improved by adding other metals into the mix.

via The Fascinating World Of Solder Alloys And Metallurgy — Hackaday