What materials are best for building a Helmholtz coil?

[hylander4]

Hello PFs,

I need to build some Helmholtz coils, and I was wondering if anybody here had suggestions on what to make the actual rims that hold the wire in a coil are generally made out of? So far its been suggested that I use bicycle rims, but even that creates a question--aluminum or steel? Should the rims be ferromagnetic or paramagnetic?

Anybody have experience building these? I was hoping to make mine about a bit less than a meter in diameter.

 

[berkeman]

Hello PFs,

I need to build some Helmholtz coils, and I was wondering if anybody here had suggestions on what to make the actual rims that hold the wire in a coil are generally made out of? So far its been suggested that I use bicycle rims, but even that creates a question--aluminum or steel? Should the rims be ferromagnetic or paramagnetic?

Anybody have experience building these? I was hoping to make mine about a bit less than a meter in diameter.

(Thread moved from GD to EE)

Is that the approximate size for your coils, bicycle wheel size? What frequency range are you going to be testing?

You should not use any conductive material for the coil supports. It will distort the field in general. You could probably use aluminum for DC B-field generation, but you should be able to figure out some plastic coil supports that will work for both AC and DC field generation.

 

[hylander4]

I haven't really been given any frequencies to test. I was assuming I'd be testing DC fields. The coils are being used to test the effectiveness of magnetic shielding, and they have to fit around a ~1m wide cylinder.

If it doesn't have to be too exact, would wood be alright? Or would wood be too apt to catch on fire?