At the suggestion of a club member, I'm looking into picking up a few spools of copper wire for my Junipers I'll be working this fall. I notice that pricing for annealed copper wire for bonsai is pretty high compared to say, copper wire used in jewelry making. I haven't come up with much information comparing annealed with "dead soft" or "Half hard" wire descriptions. Would jewelry making copper wire work harden as well as annealed bonsai copper wiring? My immediate guess is that I just should pick up the bonsai wire and quit finding ways to be a cheap bastard, but figured I'd ask anyway and see what others' experiences are in the community.
Jewelry making has been a hobby of mine for longer than bonsai. Most of what was said above was correct, but I'm still gonna rant.
Most copper jewelry wire is the same 99.999..% copper that you'll get from the bonsai suppliers, stripping electrical cable, or buying bare copper wire at Home Depot. I only say "most" because some "copper" "craft" wire may just be a copper colored aluminum.
As I'm sure you've guessed, dead soft wire is a lot softer than half hard. Bonsai people like their wire much softer than dead soft. This matters less at the smaller gauges (say, 18g to 12g or so) but becomes a really big deal when you are working with the fat stuff -- 10g, 8g, and 6g. I often make bracelets out of 6g and 4g wire. I believe that there are bonsai that need those sizes -- I just don't own any
I'm a little surprised that you found that jewelry wire is cheaper than bonsai wire. In my price checking that didn't really seem to be the case for anything larger than 20g (which isn't really a useful bonsai size). Otherwise, for retail quantities of wire, the bonsai suppliers were ahead of the game (stone lantern for 18g, Julian Adams for 16-8g) the one exception was 8g that was cheapest (in 50ft rolls) at a local hardware store (Menards).
Wholesale, I was (unsurprisingly) able to beat Julian Adams prices for 8, 10, 12, and 16g through wireandcableyourway.com. (I had previously lucked into a deal on scrap 14g so I'm set for that for the forseeable future as well) But, 100ft (and 500ft for 16g) quantity minimums may be more than you are willing to take on. Again, I have jewelry (and sculpture) uses for this stuff, and a (small) kiln which makes annealing* for my own trees easy enough.
All that being said: I wouldn't recommend buying wholesale (or scrap) and annealing your own as a good way to save money, unless you really don't value your time. It's just not *that* much cheaper, and it's kind of a pain. Which is all to say -- it's tempting to believe that the bonsai wire suppliers are adding "bonsai" tax to the price of their wire. I don't really think that they are. It does suck to pay for shipping, but if you order a sizable quantity from Gremel or Adams, you'll be set for a while and can spend more time on your trees.
*I've never used "proper" bonsai copper wire. But... I took wire from the SparkleKiln™ to a workshop with a bonsai professional and he wanted to know where I got it because my fat wire (8g) was the softest he'd ever used. I know that Gremel and Adams have their various "programs" worked out, but I just load the kiln with my spools (various gauges), ramp to 1350F over 1 hour, quench immediately, and (if I'm feeling fancy)
pickle.