If that header was glowing red during heating, it must have been steel ?? I have never seen aluminium glow, not even at the point just before you burn a hole in it. Also, it was chromed, and I have never seen a chromed aluminium header.

I think filling with sand ( for aluminium headers) is against collapsing of the material. I make all my headers myself, but bending the aluminium is always a problem []

That Skystar looks great!

KrisG