If you can make an intake plenum in cast aluminum for less than 60$ as you claim, you'll have my eternal respect, and I'll buy it from you for twice the price !
For my situation:
First, I don't have the tools, nor the place to cast anything, so that's not an option.
Second, I know most of the machine shop in my area, and none of them would do a job for less than a 100$.
And lastly, no, it won't melt, if you've read the thread you'll know.
The only problem as I mention in the thread is the low pressure inside the plenum that made it slightly deform at idle. But that will be solved with the updated version.
I saw a lot of video about sand casting stuff out of aluminium, I know what's required and everything, but the fact that a teenager can do it (I think there's a kid that's 12 and that has a channel on youtube where he casts stuff like slingshots) doesn't make it a better or easier solution.
Sure, you won't mass produce 3D printed parts, but that's not the goal here
3D printing was never and will never be used for mass production, there is no point comparing it to casting.
Ben.