This is a great idea. The "hubs" of the dome have the same angles whatever the length of the vertices of the geodesic dome. I looked into purchasing cast hubs maybe a few years ago, but could not find a supplier (was thinking of making a temporary shelter/greenhouse/barn). There was someone making hubs out of pressed sheet steel, but I was not impressed with its strength.
This sort of enterprise would flourish in a post peak environment assuming some natural gas could be obtained. Recycling aluminium into a "cottage industry" setting had great potential.
I liked seeing him use greensand for the mold. takes me back to my highschool metal work days.