Historically for "physical patents" in he US, you are free to make your own device for personal use. You could even build on as a [temporary] employee for someone else. Eli Whitney pretty much went broke on the cotton gin as a result. I'm sure the corporations would beg to differ, but it hardly matters what the law actually is these day: few will contest a threat of lawsuit.
I often joke that between his cotton gin [which vastly increased the market for slave-grown cotton) and his innovations in interchangeable parts (which finally made him rich building rifles), he pretty much made the US Civil War happen when/how it did
Software patents have philosophical issues that I don't want to tackle (Dammit Jim, I'm a doctor, not a lawyer), but if you wrote your own coder and decoder, and coded only your own data for playback by only yourself .. not I promised myself I wouldn't go there. Suffice it to say that if you wrote a program to decode a legally encoded MP3, you'd have to worry more about DMCA, because you'd be circumventing an encryption (whatever rights you'd otherwise have) Besides, MP3 is part of the MPEG-2 standard (1991?), so the original patent would likely have expired by now -- or in ca 2015, at the latest, if it was an add-on. I don't recall the details.
I did quite a bit of dallying with low-melt alloys in my youth (I frequently encountered a hobbyist writeup on SMT tricks that I posted to a mailing list under my real name, as well as my early (1996? 97? Within about a year of them marketing online, anyway) Chipquik circulating on the web 10 years later). I mention this because I still have the remainder of my very first sample from their original recipe (tossed it in a general toolkit when I bought more, but never needed to use it in "general" work) and can confirm it was quite different from the brittle stuff Dave showed (which is more like Woods, Cerro-Low, etc.) It was only moderately less flexible than 63/37
Woods metal *will* work as a low melt desolderer. and is relatively cheap in the quantities used by plumbers, AC workers, etc. for pipe-bending, heat-activated sprinklers, etc. You'll sometimes see Woods Metal sold in 100-2000g lots on eBay, crude unmarked "ingots" that were very likely just cast from scraps/blocks of old plumber's material (I once got one where I could read the embossing of the kitchen bowl they'd cast it in) IIRC, not so long ago, a 3lb block could be had for $20-30 plus s/h if you were patient. I took a quick look and found plenty of sales of "Woods Alloy", but few real bargains -- but those offers were erratic when I used to buy it.
There are a number of such low-melting alloy to experiment with: French's metal, Field's metal, Rose's metal ... it's been a long time since I was into this, so the exact details elude me. Cerrometals, on the other hand are typically sold in small quantities for specific uses (e.g. cerro-Low is used for revolver pistol chamber measurements, because it shrinks very slightly on cooling for easy separation), and tend to be much pricier (and undoubtedly purer) than their technical grade equivalents. I don't know of any cheap source for the Cerro-metals, but if I were *counting* on them, I'd go for the brand-name; chipQuik likewise can't patent an alloy that has been known and used for over a century, but it can patent a use, so no one else can sell it.
If I correctly recall the date of my review of the original ChipQuik, a 20-year patent would be running out very soon.
I would steer you clear of the (near) liquid metals. Mercury will suck gold off contacts so fast that you won't even be sure if it was ever there. Gallium (liquid at body temperature, but not *quite* at room temp, IIRC) will dissolve aluminum -- and some metal/liquid metal combos can be quite exothermic during dissolution, become exothermic on exposure to water, etc. Such metal/metal solutions are used in advanced organic chemistry to perform surprising reactions. I don't remember what Gallium does when it hits magnesium, for example, but you wouldn't want a flung droplet to hit your bike frame in the corner and start a fire that night.
Stick to low-melting solid alloys. You have to add heat, but by controlling the heat, you have more control over the physical material
It's dense, and they need to temporarily fill a fixed volume of often 100s/100cs of cc) - and they I never worried much about how to cast it into a wire, because it will stick to many materials (like the polyethylene containers I used in a water bath to melt it) creating thin "flashing" sheets that can easily be flexed off the poly and used almost as conveniently as wire. As you can see with the new Chipquik in the video, though,
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