What materials and thickness should I use for the tubs?
Documented on the Ford Mustang build
Published February 26, 2026
Common choices are 18–20 gauge mild steel for fabricating tubs; stainless or aluminum are options but require different welding techniques.
Full Answer
Common choices are 18–20 gauge mild steel for fabricating tubs; stainless or aluminum are options but require different welding techniques. Thicker metal is stronger but harder to shape—18 gauge is a common compromise.
Documented In This Build
Related Knowledge
How much extra clearance will custom fender wells give me?How do I prevent rust where I cut and weld?Do I need to weld the tubs in or can I use rivets?Will cutting the inner fender affect structural integrity?How do I prevent warping when welding thin sheet metal?What wheel/tire sizes can this modification accommodate?How much extra tire/wheel clearance can I expect?How difficult is this for someone with limited metalworking experience?
Related Parts
Seam sealer
$12
MIG welding wire
$15
Primer (self-etch or epoxy)
$30
18 gauge mild steel sheet (or equivalent sheetmetal)
$60
Pop rivets / rivet nuts
$10
Wheel tub / inner fender panel (replacement or prefabricated kit option)
$120
Shielding gas (MIG mix)
$30
Body filler (Bondo) / finishing materials
$15
Topcoat / bedliner / underbody coating
$60
Rust inhibitor / etch primer (optional)
$20
Related Tools
Jack and jack stands
MIG welder
Clamps (sheet metal clamps / C-clamps)
Angle grinder with cutoff wheel and flap disc
Electric or air drill (with hole saws / spot weld cutter)
Metal snips / aviation shears
Metal hammer and dolly set
Measuring tools (tape, straightedge, scribe)
Rivet gun / rivet nut tool (optional)
Related Videos
From cuts to custom fender wells on my Mustang - FINAL
From cuts to custom fender wells on my Mustang Pt 6
From cuts to custom fender wells on my Mustang pt 2
From cuts to custom fender wells on my Mustang Pt 5
From cuts to custom fender wells on my Mustang
From cuts to custom fender wells on my Mustang part 3