I'm making a seat bracket for my Sparco EVO seat in my track car. I bought a set of OMP aluminum side mounts that are quite beefy (5mm thick) to mount the seat to my bracket. In time, I'll fabricate the side mounts too, but for now, I'm going to use the OMP mounts to bolt to the seat and the mounting bracket that will bolt into the stock seat mounting bolt holes.

I don't know why it didn't dawn on me sooner, but I know that 6061 aluminum looses it's strength when it's welded by quite a large margin. I'm using 0.1875 x 3" aluminum for the side pieces, and I'm welding the ends onto it that will bolt into the car chassis. I planned on strengthening it with some stringers on the sides, but again, the aluminum will lose some strength with the welding. Do you guys think that aluminum of this thickness is sufficient to securely hold the seat in an impact, or should I go with mild steel? I was thinking of ordering 0.125" 1018 cold rolled mild steel to make the same seat bracket.

Thanks for the advice!

 

Use steel.