Does anybody know where I can get some cheap aluminium to make a flywheel?
I live in WA? Please don't say scrap metal place (unless u know of one which gets large pieces) Buying new, seems like it would be quite expenssive??

Don't know what companies you have over there but somone like Capral Aluminium should have what you are looking for.

You will need to get the right grade of aluminium also to suit what you are trying to use it for.

Not over expensive, the machine work is usually the expensive part of an alloy flywheel.

Aluminium is pretty bloody expensive. In NZ it is anyway. Have you thought about making a steel one, it would be a lot cheaper.

possibly head down to henderson, and ask one of the boat building companies there for a bit... seems to be no shortage of aluminium there

I got my alloy one made in Melbourne cause I couldn't find anyone competant to make me an alloy or steel one here in Perth

But yes once you find out the grade you should be using start the ring around.

Cheap grades of aluminium + flywheel in the one sentence= big banga boom!!!!
The right grades are not cheap.

Like Feral says, wrong grade of alloy & you got problems.
So what IS the right minimum grade? I don't know,... or care, as i'm not making a flywheel, but you would be wise to find out, & care a lot, as the wrong chioce could equal one very unhappy Datsun driver.

Will you be machining it yourself, or paying someone? How do you propose to securely fit the friction surface insert?

I don't know the actual grade of material
But this is what it looks like when finished

quite a bit of work in one of those...
unless you're a competent machinist you'll have to pay ####loads to get one made, and if you were a competent machinist you would more than likely know where to buy the material
If you are paying someone to do the job, why not just let them worry about where to get it and the correct alloy to use? They will probably put on their margin but they will buy it cheaper than you could anyway, so in the long run probably not much difference in price but less hassle for you.