Doubling up copper bonsai wire

[August44]

I think I remember seeing a chart somewhere telling what gauge copper wires turned into if they were doubled. Does anyone have a copy of that? I do remember that if you combined 2, 8 gauge wires you did not have the equivalent of a 4 wire.

 

[WNC Bonsai]

It would also be nice to have the same chart for aluminum and one comparing copper and aluminum.

 

[jeremy_norbury]

I thought that copper and aluminium acted the same in terms of doubling - but even that changes, apparently.

We care most about flexural rigidity.

I asked Copilot to make be a couple of tables and it came up with these:

Copper

Wire Diameter (mm)	Flexural Modulus (GPa)	Moment of Inertia (mm^4)	Flexural Rigidity (GPa·mm^4)
1.0	115	0.049	5.64
1.5	115	0.199	22.89
2.0	115	0.785	90.28
2.5	115	2.448	281.52
3.0	115	5.940	683.10
3.5	115	11.95	1374.25
4.0	115	20.11	2312.92
4.5	115	31.05	3570.98
5.0	115	44.41	5107.34
5.5	115	59.82	6878.50
6.0	115	77.94	8966.31

Aluminium

Wire Diameter (mm)	Flexural Modulus (GPa)	Moment of Inertia (mm^4)	Flexural Rigidity (GPa·mm^4)
1.0	69	0.049	3.38
1.5	69	0.199	13.73
2.0	69	0.785	54.17
2.5	69	2.448	168.91
3.0	69	5.940	409.86
3.5	69	11.95	824.86
4.0	69	20.11	1387.59
4.5	69	31.05	2142.60
5.0	69	44.41	3064.16
5.5	69	59.82	4137.51
6.0	69	77.94	5378.86

For small gauges every 0.5mm diameter increase is like 3-4X stronger - so you need 4 strands of 1mm wire to be equivalent to 1 strand of 1.5mm wire.

When you get to 3mm it's 2X stronger and at 5mm even less.