Wire bending and wrapping — thinner than ¼" (4 AWG)

For functional pieces, one of the important things to get right is 1) how hard is the wire that you start with (AKA wire temper), and then 2) how much work-hardening do you do to the wire before it's finished:

• Jewelry Tutorial HQ
  • Wire hardness explained.
  • What is work-hardening?
  • How to work-harden.
• Choosing what wire to use.
• ▶by Aaron McDonald
• ▶Lots of videos by DIY Keychain

Marble track:

• ▶How to make a steel marble track, step-by-step | Daniel de Bruin
• ▶How to make a steel marble track | Bit Machines
• ▶@Copper-Gravity
  • ▶Building a marble run, time-lapse with commentary
  • ▶Building another marble run, time-lapse
• advice on using a small torch to solder: [1]   [2]   [3]   [4]   [5]   [▶6]   [6]
  • Lexivon butane soldering
  • Bernzomatic FirePoint Creator Tool — Capable of 2000°C if propane, and 2200°C if MAPP gas.
  • Oxy/propane or oxy/MAPP — Not worth it, because the Turbo Torch is about as good, but is more compact since it's only one cylinder.
  • Turbo Torch — acetylene and air — Capable of 1600°C.
  • O/A torch — Capable of 3100 to 3500°C.