Rust Repair and Panel Replacement That Lasts
Rust is the number one enemy of classic cars, and dealing with it properly is one of the most important jobs in any restoration. Whether you're in South Sioux City or Wayne, at Mohnson Fab we don't patch over problems — we cut out the damaged metal, assess the full extent of the corrosion, and replace it with fresh steel that's properly fitted and welded. Whether it's a small patch in a fender or a full floor pan replacement, the repair is done to last decades, not just pass inspection.
We handle the full range of body panel replacement work: quarter panels, rocker panels, floor pans, trunk floors, wheel wells, door skins, cowl panels, and more. When aftermarket replacement panels need modification to fit correctly — and they usually do — we have the equipment and experience to make them right.
Proper Repair Starts with Proper Preparation
Every rust repair begins with fully exposing the damage. Surface rust is often just the visible tip of much more extensive corrosion hidden beneath undercoating, seam sealer, and overlapping panels. We strip back everything necessary to find solid metal, then mark our cut lines with clean margins beyond the rust.
Replacement panels are trimmed, fitted, and clamped in position before any welding begins. We use a combination of TIG and MIG welding depending on the panel thickness and location, with careful heat management to minimize warping. Butt welds are used wherever possible for a clean, strong joint that finishes flat. After welding, every seam is ground and metal-finished so the repair blends seamlessly into the surrounding body work. For trunk floors, cowl panels, and wheel well repairs that need formed sections, we use the English wheel to shape repair patches with the correct contour, the metal brake for clean bends on flanges and mounting edges, and the planishing hammer for final surface finishing. These tools let us match factory panel profiles precisely, even on compound-curved areas where off-the-shelf replacement panels fall short.
Panel Work for Classic Cars, Muscle Cars, and More
Rust doesn't discriminate, and neither do we. Our Dakota City shop handles body panel replacement on classic cars, muscle cars, hot rods, vintage trucks, and any other vehicle that needs solid metal where rust has taken hold. We regularly work on cars from across the region — owners from Sioux City, Omaha, Lincoln, Sioux Falls, and Des Moines bring their vehicles to us because they know the panel work will be done correctly, with attention to fit, finish, and long-term durability.
Equipment & Tools
Vehicle Types
Other Services
1965–1970 Mustang Restoration
Dedicated first-gen Mustang expertise with factory-spec structural accuracy on a purpose-built unibody chassis fixture.
Classic Car Restoration
Over 20 years of hands-on experience restoring pre-1970 vehicles — American muscle, British sports cars, Italian exotics, and everything in between.
Hot Rod Fabrication
Hand-formed panels, one-off metalwork, and custom fabrication — building something that's never existed before.
Custom Metal Shaping
English wheel, power hammer, and hand-forming techniques — shaping flat sheet into compound curves and finished panels.
Chassis & Structural Repair
Professional chassis table work with factory-spec measurements — structural repair done with the accuracy your vehicle demands.
Ready to Start Your Project?
Get in touch to discuss your restoration or fabrication project. We'll provide an honest assessment and a fair quote.
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