Deer Meadow Bonsai

More About Annealed Copper Wire

Why Anneal?

Annealing is a process of heating a metal so as to make it softer. The effect is particularly strong for copper, so annealed copper is much, much, much softer than unannealed copper.

Bending annealed copper wire causes it to work harden, which reverses the annealing. So, annealed copper is soft when we apply it to our trees and it gets much harder as we do so. This is sort of magical and is the main reason that copper wire is often superior to aluminum wire for bonsai: The wire is soft going on, but it gets harder in the process and thereby holds the branch or trunk as if it were a much larger wire!

But (...and there’s always a ‘but’...), we don’t want the wire to harden before it gets to the tree. So to minimize ‘pre-wiring hardening’, users should (a) protect the wire from deformation in storage, travel, etc. - don’t let it get knocked around - and (b) minimize the hardening that occurs as a piece is straightened from the coil just before using. This is nearly insignificant for very thin wires, but very important for heavy wires - they will be dramatically hardened if they are annealed in small diameter coils then straightened out for application.

So I make heavy wires into large diameter coils and fine wires into smaller diameter coils.

My Life as a Wire Monger

After 17 years as an engineer with McDonnell Douglas, I left to become a full time potter in 1984. I made decorative vases, bowls and platters for galleries and stores all over the US (and still do). My bonsai suffered through a few years of neglect, but as my pottery became more successful, I had more time to spend on the hundreds of trees in pots and in growing beds in my small backyard in Berkeley. In 1995 I moved to Sonoma County where I have five beautiful acres and, now, a bonsai nursery and this website!

I have always used copper wire on my trees - that’s all there was when I started in the mid 70’s. Since I was able to anneal my own, I never switched when aluminum became available. Several years ago, copper came back into vogue, so I began to anneal wire for friends. Finally, the price of the imported wire was so high that more and more people wanted me to supply it for them and I began to sell annealed wire.

When it was just for my own use, I used scrap wire. As I began to sell it, I realized what an enormous amount of labor it took to straighten and coil scrap wire and that I could never charge enough for the finished product so as to make the effort worthwhile. So I began to use new wire. I coiled the wire using one of my potter’s wheels, heated it in an outdoor kiln and quenched it in water.

My customers loved it! Both the quality (not all “annealed” wire is as soft as mine; I have heard of unevenly annealed wire that has hard and soft spots) and the price, because my wire was less than half of the price of imported copper wire.

I didn’t measure the wire when I made the coils, I just made them in what my experience told me would be good amounts. Larger diameter coils for heavier wire and smaller for lighter wire. When a customer wanted wire, I piled it up on a scales, weighed the total and charged by the pound (like buying meat from the butcher).

I’m still coiling and annealing the wire pretty much as described above, but I have gradually learned how to make the wire even softer than before. And I have standardized my coil weights, so I no longer have to weigh every coil as it is purchased.

I’ve been selling the wire for many years now, and my customers are happy with it. I am grateful to Kathy Shaner and Boon Manakitivipart and other noted sensei’s for referring many of their clients and students to me.

Japanese Wire vs Mine

1. Wire gauges are different in the US and Japan. Their # 6 wire is equivalent to my #4 gauge. Their #8 is my #6, their #10 is my #8, and so on. I didn’t invent this difference, I simply use the standard AWG sizes for wire made and used in the US.

There is no relative advantage to either numbering scheme.

2. Japanese wire is of excellent quality. I generally expect my wire to be better annealed than other domestic wire, but I do not expect it to be any better than the Japanese wire.

3. Japanese wire is normally available in large diameter 1 kilo rolls. That is fine for heavy wire, as 1 kilo of #4 is less than 20’ of wire. One kilo of fine Japanese wire, however, often becomes a tangled mess because (1) fine wire is so soft that it is difficult to maintain the shape of a large diameter coil and (2) a kilo of fine wire is a huge length of wire - way more than most users would need.

I make my wire into conveniently sized coils that give a good balance between having a good amount of wire, but not so much as to be unwieldy. And I make the smaller wires in smaller diameter coils that are easier to handle and are less likely to become tangled “bird nests”.

4. Japanese wire is much more expensive than my wire. It costs more per pound (or kilo) and you have to buy way more of the small wires than you need.

Storing Copper Wire

There are two considerations: convenience and protecting the wire from being deformed (and therefore hardened) before you use it.

You may have more elegant ideas, but I recommend storing and carrying your annealed wire in a cardboard box. A 12” x 12” x6” box will easily hold one coil of each size. If you are careful, that is all you will need.

For most people, however, the wire box gets jostled around and the heavy wires beat up the small wires, so you should separate the four smallest sizes - 16 through 22 - from the larger wires. You could use a separate box, or make a topless cardboard tray about 8 inches square by 1 1/2 inches high. Put the small wires in the tray and carry the tray inside your wire box, on top of the heavier wire.

I use a more elaborate version. I made nesting trays - one tray for each wire size - so none of the wires get tangled with the others. The trays keep my wires separate and undeformed for maximum softness.


Annealed Copper

Copper vs Aluminum

Anodized Aluminum

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