How do I protect the repaired area from rust and road debris?
Documented on the Ford Mustang build
Published February 26, 2026
Use seam sealer on all joints, primer and a topcoat of paint, and reinstall or fit an inner liner.
Full Answer
Use seam sealer on all joints, primer and a topcoat of paint, and reinstall or fit an inner liner. Undercoating or rubberized spray can add extra protection against stone chips and moisture.
Documented In This Build
Related Knowledge
How do I prevent warping when welding thin sheet metal?What wheel/tire sizes can this modification accommodate?Do I need to weld the new fender wells, or can I rivet/bolt them?Will modifying the inner fender affect vehicle safety or inspection?How much extra tire/wheel clearance can I expect?How difficult is this for someone with limited metalworking experience?How much wheel/tire clearance should I leave when shaping the fender well?How long does a project like this typically take?
Related Parts
Sheet metal (mild steel) - 18-20 gauge
$50
Universal inner fender liner / splash shield
$30
Seam sealer (automotive)
$10
Pop rivets / sheet metal screws
$5
MIG welding wire / shielding gas (consumables)
$20
Body filler (Bondo or similar)
$12
Primer and paint (rattle cans or small kit)
$40
Related Tools
Measuring tape and marker
Angle grinder with cutting and flap discs
MIG welder
Reciprocating saw / metal cutting saw
Drill and spot weld cutter / drill bits
Hammer and dolly set
Clamps (C-clamps / locking pliers)
Body sanding blocks / orbital sander
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