How should I protect the new metal from rust?
Documented on the Ford Mustang build
Published February 26, 2026
Use a weld-through primer on seams during welding, seam sealer on joins, and follow with epoxy or zinc-rich primer and appropriate topcoat or undercoating to seal the inside of the wheelwell.
Documented In This Build
Related Knowledge
What welding technique is recommended?Do I need to use preformed tubs or can I fabricate from sheet metal?Will this modification affect vehicle legality or safety?How much clearance should I allow for larger wheels/tires?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
MIG welding wire (ER70S-6, 0.030-0.035" spool)
$30
Grinding / flap discs (pack)
$20
18 gauge cold-rolled steel sheet (for tubs)
$60
Preformed wheel tubs (alternative)
$250
Seam sealer / panel adhesive
$10
Weld-through primer / zinc-rich primer
$25
Automotive body filler (Bondo or equivalent)
$15
Self-tapping screws / rivets & nutserts (fasteners)
$10
Related Tools
Hammer and dolly set
Spot weld cutter / drill
Angle grinderDeWalt DWE402
Sheet metal brake / metal folderEastwood Leaf Break (or equivalent)
Measuring tools and markers (tape, scribe, straightedge)
Clamps and cleco fasteners
MIG welderLincoln Electric LN-140 (or equivalent)
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 4
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