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.
Doubling up copper bonsai wire
- Thread starter August44
- Start date
WNC Bonsai
Masterpiece
It would also be nice to have the same chart for aluminum and one comparing copper and aluminum.
jeremy_norbury
Omono
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
Aluminium
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.
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.
Great job Jeremy. I'm gunna whisper to you real low that I don't understand the meaning of anything in the charts except the mm section. The rest, help please. Also cause you the smart guy, if I put #6 gauge copper on and it wasn't enough, so I doubled it with another one, how much stronger would the wires together be verses just one wire and how many 6 gauge would I have to put on to double it? If figuring that all out is a pain, don't do it. Just curious. It sure is backwards to what I was thinking. Thanks for your efforts.
19Mateo83
Masterpiece
Don’t feel bad…. I’m scratching my head looking at those tables as well.
jeremy_norbury
Omono
@August44 @19Mateo83
Yeah - I don't invent these things, it's an engineering thing and I'm not one of those, I'm a computer scientist - which is why I can plagiarize data efficiently.
Yeah - I don't invent these things, it's an engineering thing and I'm not one of those, I'm a computer scientist - which is why I can plagiarize data efficiently.
- The lovely people at Carrera Casting have a freedom units to mm conversion table here: https://www.carreracasting.com/charts/wire-gauge
- It looks like 6 gauge wire is very close to 4mm.
- 4mm copper wire has a "resistance to bend" value of roughly 2300 units.
- to double that, you just use 2 wires
- HOWEVER, if you happen to have 5 gauge wire (more or less 4.5mm or just 0.5mm thicker) - its already 50% stronger than the 6 gauge.
- And more importantly, if you have 4 gauge - which is roughly 5mm in diameter it is already more than 10% stronger than 2x 6gauge. (2x2300 =4600 vs 5100)
jeremy_norbury
Omono
So just a little bit more juggling and we end up with this equivalency table in US wire gauges
How to read it:
Wire Flexural Rigidity Equivalents (Copper and Aluminum) in US Wire Gauge
In very simplistic terms each gauge up in size ( lower gauge number ) roughly doubles the stiffness.
How to read it:
- Say we have gauge 8 wire - what is the equivalent stiffness in other gauges?
- go down the left and find 8
- go across and we see under gauge 12 - we need 16xG12 to be equivalent to 1 strand of gauge 8
- We have gauge 5:
- down to 5 and across
- we need either 4x G7 or 2x G6 to be equivalent.
Wire Flexural Rigidity Equivalents (Copper and Aluminum) in US Wire Gauge
| Gauge Diameter (mm) | 18 (1.02mm) | 12 (2.05mm) | 9 (2.91mm) | 8 (3.26mm) | 7 (3.67mm) | 6 (4.12mm) | 5 (4.62mm) | 4 (5.19mm) |
|---|---|---|---|---|---|---|---|---|
| 18 | 1 | - | - | - | - | - | - | - |
| 12 | 97 | 1 | - | - | - | - | - | - |
| 9 | 794 | 8 | 1 | - | - | - | - | - |
| 8 | 1612 | 16 | 2 | 1 | - | - | - | - |
| 7 | 2756 | 27 | 4 | 2 | 1 | - | - | - |
| 6 | 4629 | 45 | 7 | 4 | 2 | 1 | - | - |
| 5 | 8073 | 78 | 13 | 6 | 4 | 2 | 1 | - |
| 4 | 13741 | 133 | 22 | 11 | 6 | 4 | 2 | 1 |
In very simplistic terms each gauge up in size ( lower gauge number ) roughly doubles the stiffness.
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