How to MIG Weld Auto Body Panels


MIG welding body panels can be tricky because they are so thin. Thinner metals require lower welder settings and some technique. With some practice, however, welding auto body panels becomes much easier. The trick is to get a solid, strong weld without warping or burning through the material. It is a very good idea to practice on some scrap sheet metal if you have any. That way, the mistakes you make while learning won't be evident on an important project.

Things You'll Need

  • MIG welder
  • Auto body sheet metal
  • Welding hood and leather gloves
  • Grinder
  • Tin snips
  • Primer
  • Cut the sheet metal precisely. One of the most important things to do when welding thin metals is to make sure the gap is as small as possible, and the pieces fit together extremely well. A quality pair of tin snips can make the job a lot easier. Bridging a large gap is not fun while doing any sort of welding, but it is next to impossible when MIG welding on auto body material. You can use an angle grinder to finely shape the pieces so that they fit as exactly as possible.

  • Tack weld everything first. Never attempt to simply completely weld up any body panels, because the heat will warp them quickly. Instead, tack weld them together every few inches, allowing everything to cool between arcs. To tack weld them, simply pull the trigger on the MIG gun for only two seconds or so. The goal is to stick them together well enough so that the panels won't separate, while at the same time avoiding burning through or warping the sheet metal. Do not bother grinding the tack welds once they are completed, because you will be welding more on the panels.

  • Fill the gaps with weld. Now that the body panels are tacked together, you can slowly connect them by welding the seams. It is important to go very slowly, welding only two to three inches at a time. "Pull" the gun away from the weld at a 45-degree angle to avoid deep penetration. Let the entire weld cool before striking another arc to avoid warping. If you can access the back side of the body panels, check to make sure there is no burn through from there. Sometimes it is very hard to see what is happening from the front side only. If the back of the sheet metal is turning black or you are seeing holes, turn the settings down on the welder a bit and try again.

  • Grind the welds down. Once the body panels are completely welded, it will be necessary to smooth the welds down so that they are flush with the rest of the sheet metal, and no longer visible. After the welds are ground down and the body panel is straight, you can coat the area with primer to prevent rust from forming.


  • "Welder's Handbook, RevisedHP1513: A Guide to Plasma Cutting, Oxyacetylene, ARC, MIG and TIG Welding;" Richard Finch; 2007
Promoted By Zergnet


You May Also Like

  • How to Weld Sheet Metal Together

    This article is aimed at taking you through some basic steps involved with tack welding sheet metal together using a Metal Insert...

  • How to Weld Auto Body Panels

    Untreated rust on a car is like an untreated disease: The longer the rust remains, the larger the spot will become, spreading...

  • How to Weld Patch Panels

    Rust can creep up on your car and do plenty of damage before you notice it. It can appear under the he...

  • How to Weld a Body Trim Hole

    Filling body trim holes in thin gauged steel auto body panels requires the use of a MIG welder. To prepare the body...

  • How to Weld Quarter Panels

    Road salt and moisture cause the rear quarter panels of older vehicles to rust. When left unchecked, the rust will grow into...

  • How to Replace Auto Body Panels

    Many times when a car is damaged in a collision or has a rusted area that is beyond repair, the damage is...

  • How to MIG-Weld Patch Panels

    MIG welding, or metal inert gas welding, is the simplest type of arc welding to learn. A MIG welding torch delivers electric...

  • How to Fix Auto Body Repair Panels Without Welding

    An auto body repair or restoration project can often come to a sudden halt if welding is required. Welding requires extensive specialist...

  • How Car Panels are Replaced

    Replacing car panels--how to weld, where to clamp and what to caulk--is explained by our expert in this free auto-body repair video.

Related Searches

Check It Out

How to Build and Grow a Salad Garden On Your Balcony

Is DIY in your DNA? Become part of our maker community.
Submit Your Work!