Custom Metal Finishing: Patching with a MIG Welder

At Customs & Hot Rods of Andice, we use a variety of tools to complete our custom builds and vintage restorations. Our arsenal includes equipment like TIG and MIG welders, which are vital to our custom metal finishing work.

While TIG welding equipment is out of the price range of many hobbyists, MIG welders are more economical. These welding tools are a must for any DIY'er who wants to do minor custom metal finishing on their own, such as removing rust and patching automotive panel damage. Here are some tips on how to effectively use your home MIG welder:

Custom Metal Finishing 101: Patching with a MIG Welder

• Remove ALL rust and corrosion on a panel. The number one mistake that MIG welding newbies make is being too hesitant to rout out all rust and corrosion. Many owners fear that being too aggressive might cause damage, but if you don't remove all rust and corrosion now, it will spread and cause bigger problems down the line.
• Thoroughly clean the weld surface. Failing to pre-cleaning the welding surface is a leading cause of ugly and weak welds. Use 60 grit to remove old paint, primer, and fill so you start your work with bare metal. Finish with a wax/grease/paint remover to get rid of any residual materials.
• Set the welder to clean burn and fill the gap. It's tempting to set your welder at a low voltage, but you will get the best results with a hot, clean burn with localized heat distribution. This will allow you to stack up spot welds to fill the gap, which can then be ground down without porosity issues.
• Grind the weld flat. Once the welds have set, use a low grit sanding disc -- preferably on an air-pressured grinder -- to grind the weld flush with the rest of the panel. An air pressured-grinder won't add excess heat to the custom metal finishing, which could potentially distort your work.
• Inspect for flushness. Work slowly when grinding and check your progress often, as it's unlikely you'll get the panel flush on your first try (but big congrats if you do!). One of the best methods for checking for flushness in your custom metal finishing is with a guide coat. Guide coats come in wet and dry versions and are applied over the panel work. Follow the manufacturer's instructions on sanding and wiping these coats down to reveal any low or troubling areas.

Got a Big Custom Metal Finishing Job? Contact CHRA

Have an automotive metal project that is bigger than a little rust? Talk to our team at CHRA -- your local Texas experts on auto builds, hot rod restorations, and custom metal finishing.