Two racks
The black rack uses standard-diameter tubing (though, really, I could have used quarter-inch tubing for such a tiny rack), the orange one (destined for the kit bike – the hideously steep HTA makes my normal-offset fork teeter on the edge of low trail, so a larger rack + bag might settle the high-speed shimmy it sometimes gets) uses oversized (3⁄8“) tubing.
It might be the paint, but it’s not immediately obvious that the O/S rack is made of larger-diameter tubing than 5⁄16“ standard tubing. It’s considerably harder to work, but that’s not immediately visible when I look at the final product.