Throttle butterfly flap material

[Hoofa]

Ok what should it be made out of, brass or ally ? Or does it not really matter ? Someone must know ?, help,please chaps

[Pupp]

I'd be a little cautious of brass if metahanol features significantly in your plans at all, it reacts.

That apart, I'd have thought the biggest issue is going to be machining it to the necessary 'eliptical' edge profile so as to get a good seal...