I still have tiny scars on my thighs from when I taught myself to solder electronics at age 13 during a hot Summer. I made the quickly-realized mistake of wearing shorts, although it was so hot that I kept wearing shorts and figured out how to position things so that I didn't splatter molten solder on myself (it doesn't mix well with synthetic fabric shirts, either!
It's been really nice to see areas set up at Maker Faires, Fixit Clinics, and similar events dedicated to teaching kids (of all ages) how to solder, among other skills. That single skill seems to be the biggest hurdle standing between most people and their learning about how electronic things work. However, once they've learned it, they tend to become much more adventurous about taking things apart to see how they work, as well as building projects, often just for fun.
Soldering metals for mechanical purposes is distinct from brazing, welding, etc., in the kinds of materials, heating sources, and temperatures involved. Copper sheet soldered with lead-tin alloy filler material (solder) is the most common, but, it can also be accomplished using brass, bronze, nickel, and tin sheet metal. It's used all the time to build model railroad locomotives and cars, automobile models, hand-made crafts, as well as cooking implements, connecting plumbing pipes/fixtures/connectors, etc. Soldering is generally accomplished using filler materials with relatively low melting points between 400 and 800 degrees F, primarily lead-tin alloys of various percentage mixtures around 70/30% ~ 60/40%. Lead-free applications now use tin-silver-copper, tin-silver-copper-bismuth, tin-silver-copper-antimony, or silver-copper alloy filler materials, depending on whether manual, wave, or other automated flow techniques are used.
Brazing almost always involves direct gas-combustion torch or furnace heating, rather than an electrically or gas-combustion heated iron typically used in soldering. Brazing also uses filler materials with higher melting points than those for solder alloys, primarily aluminum-silicon, copper, copper-silver, copper-zinc, gold-silver, nickel alloy, silver, and amorphous brazing foils containing nickel, iron, copper, silicon, boron, or phosphorus. Just to confuse things, there are products called "silver" solders, but, they're actually silver-bearing alloys containing copper, zinc, or cadmium - the process of "silver soldering" is also known as "hard soldering" or "silver brazing" because of the higher temperatures needed relative to those used in soldering, e.g., via direct gas-combustion torch heating.
Welding uses the same, or similar, pure metals or alloys for both the material being welded and the filler material and requires much higher temperatures than soldering or brazing to reach the melting point of the welded material, typically thousands of degrees F, depending on the material.