Chevy Tips and Tech - Welding Basics

Sucp 1109 Tips On Welding Welding Basics 002

Welding can be a scary thing for the novice Chevy builder. While not difficult per se, if you've never used a welder before and your Bow Tie needs some new metal installed, it can be a daunting task.

Sucp 1109 Tips On Welding Welding Basics 004

1 The same as carpentry, the first thing to do before cutting any metal out is measure, measure, mark, then measure some more. Blindly cutting away metal can put you in a real jam, especially if you cut away metal that’s not part of your replacement part. Here, we’re marking the area where we need to install a new floorpan.

1 The same as carpentry, the first thing to do before cutting any metal out is measure, m

The nice thing about our modern age (or at least compared to when cars were being restored in the '80s and early '90s) is that welding equipment is cheaper than ever to purchase, and the newer DIY-oriented welders have many automatic features that make the process even easier for a first-timer. Miller Electric's Millermatic series and Lincoln Electric's Power MIG series welders are great examples of user-friendly equipment featuring many automatic functions that make welding easy. Plus, these units come in at under $1,000-a real bargain.

On the electric side of welding, besides the commonly known arc welding, you have MIG (metal inert gas) and TIG (tungsten inert gas) welders. TIG welding is usually reserved for more experienced welders, so we're just going to focus on the MIG side.

MIG welding (also known as gas metal arc welding-GMAW) is a semi-automatic or automatic arc welding process where a spool of wire electrode and a shielding gas are fed through a welding gun. A constant voltage, direct current power source is most commonly used with MIG, but constant current systems, as well as alternating current, can be used. There are four primary methods of metal transfer in MIG, called globular, short-circuiting, spray, and pulsed-spray, each of which has distinct properties and corresponding advantages and limitations.

Developed in the '40s for welding aluminum and other non-ferrous materials, MIG was soon applied to steels because it allowed for lower welding time compared to other processes. The cost of inert gas limited its use with steels until several years later, when the use of semi-inert gases such as carbon dioxide became common. Further developments during the '50s and '60s gave the process more versatility, and as a result it became a highly used industrial process.

Today, MIG is the most common industrial welding process, because of its versatility, speed, and the relative ease of using the process in automated robotic welding. Car companies iuse MIG welding almost exclusively. Unlike welding processes that do not employ a shielding gas, it is rarely used outdoors or in other areas of air volatility. A related process, flux cored arc welding, often does not utilize a shielding gas, instead employing a hollow electrode wire that is filled with flux on the inside.

While working on our Project XS Chevelle and '55 Bel Air at Classic Automotive Restoration Specialists, we took a few minutes to make notes about some stuff that the first-time welder would find helpful before he starts performing surgery on his classic Chevy.

Before getting started on your car, the best thing you can do is get some scrap pieces of metal to play around with and use for getting familiar with the particular welder you've got. Scrap metal can help you hone your skills, experiment with different beading techniques, and allow you to play a bit and get a feel for the whole process of MIG welding.

It's really not that hard, and with some practice and patience, you can learn how to fix your car's metal and feel the satisfaction of doing the job yourself. You may even save a few bucks in the process.

2 You can remove rusted metal with either an acetylene torch, plasma cutter, or air-powered cutoff wheel. Here we’re using a plasma cutter. When using a plasma cutter or torch, use extra care and caution for what’s on the other side of the metal. The heat and sparks can easily catch old gunk and oil on fire. You’ll notice that we’re cutting well inside our mark—this is intentional. In our floorpan’s case, not all the metal was bad, and when you’re restoring a car, the more factory sheetmetal you can retain the better.
2 You can remove rusted metal with either an acetylene torch, plasma cutter, or air-power
3 Once the old piece of metal is out, it can be a useful template for trimming your new piece down to fit your car (and give you an idea of how much you’ve got to work with on the new piece). We ended up removing more old metal after comparing our first cut with the new floorpan section.
3 Once the old piece of metal is out, it can be a useful template for trimming your new p
4 To prevent future rust, and if your car is a long-term project that will span months or even years, it’s best to protect your new metal with some sort of weldable primer material. Don’t make the mistake of using POR-15 or similar products on surfaces to be welded. POR-15 is an insulator and can’t be welded through. For our panel, we sprayed the welding surfaces with this copper weld-through primer then covered the non-welding areas with a red oxide primer. You can also use brush on zinc primer, which will protect metal from rust and maintain a conductive welding surface.
4 To prevent future rust, and if your car is a long-term project that will span months or

5 At the factory, metal parts were assembled using massive spot weld guns. For the at-home guy, plug welding can be used to simulate factory spot welds. Plug welding is sometimes the best option for attaching panels anyway, especially where you have “tabs” or bends butting up next to other panels. Here, we’re using a pneumatic punch to make holes along the rocker side of our floorpan for attachment to the rocker.
5 At the factory, metal parts were assembled using massive spot weld guns. For the at-hom
6 You have some different options for holding your new panel in place while you set up to weld it in. Large C-clamps and Vise-Grips are a common method. At bottom left you can see where we’ve used Cleco rivets to affix part of the panel. Cleco rivets are useful if a panel needs to stay in place for an extended period of time before welding.
6 You have some different options for holding your new panel in place while you set up to
7 Here’s an example of plug welding. Once we’re sure the floorpan is in place and the other welding done, we’ll come back and grind these down to smooth them out and make them look like factory spot welds.
7 Here’s an example of plug welding. Once we’re sure the floorpan is in place and the oth

8 When dealing with tight corners combined with sharp bends, it can help to make a cut in the new panel’s bend to help get it fitted in place and match the corner of the original metal/section of the car. Once everything’s in place, you can weld up the cut then smooth it out so no one will ever know it’s there.
8 When dealing with tight corners combined with sharp bends, it can help to make a cut in
9 Using the outside of the car, we’ll show you a few more tips. Most old Chevys (including our subject ’55) tend to have a lot of Bondo hiding underneath multiple layers of paint. To get a good idea of what you’re dealing with and what exactly needs to be repaired, using a dual-action sander to strip everything away works great. After removing thick layers of body filler, you can see where a typical dent puller repair job was done using rivets (the small spots of Bondo in the upper right).
9 Using the outside of the car, we’ll show you a few more tips. Most old Chevys (includin
10 When tacking in a new piece of sheetmetal, space your tacks far enough apart so you don’t get heat buildup in the panel that will cause warpage. Also try to use as few tacks as possible. If you have to break the panel loose again for realignment or some other reason, this will save you a lot of work.
10 When tacking in a new piece of sheetmetal, space your tacks far enough apart so you do

11 A typical MIG welder from manufacturers like Miller or Lincoln is extremely affordable these days (under $1,000) and offers the DIY’er at home the ability to do more metalwork than was possible in the past. They’re also small and easy to maneuver around a two-car garage, especially when mounted on a dedicated cart like this one. Another advantage is small MIGs run off standard 110 household current.
11 A typical MIG welder from manufacturers like Miller or Lincoln is extremely affordable
12 The particular MIG welder we were using was a Millermatic 175. It will weld up to 1/4-inch-thick pieces of steel—perfect for most car projects—and is super easy to use. On the inside door of the welder is a chart that gives you the corresponding wire speed and voltage settings for a given thickness of steel. Lincoln Electric offers similar units that work the same way. You can also get some cool accessories for small welders like this one, such as a spool gun for welding aluminum.
12 The particular MIG welder we were using was a Millermatic 175. It will weld up to 1/4-
13 After you’ve fully welded in a panel, don’t worry if you have a fairly ugly welding line. This blemish is easily cleaned up with a coarse sanding/grinding disc. Once the welded seam is smoothed out and covered with some filler primer, you’ll never know it was there. Just be careful when grinding on the seam that you don’t go too far and totally grind away your weld.
13 After you’ve fully welded in a panel, don’t worry if you have a fairly ugly welding li

14 Here is an assortment of the basic types of clamps that will make welding at home a lot easier. You can pick these up from most tool suppliers including Harbor Freight, Sears, Home Depot, Lowe’s, Snap-on, etc. Buying an assortment of sizes is good too, so you’ll have clamps for just about every area of the car.
14 Here is an assortment of the basic types of clamps that will make welding at home a lo
15 This is a TIG (tungsten inert gas) welder. TIG welding requires more skill and patience than MIG welding, but offers the advantage of less generated heat, more control over the weld, and the ability to weld very thin pieces of metal and non-ferrous metals such as aluminum, magnesium, and copper alloys. TIG welding can be fun and offers some interesting creative opportunities when building a car, so if you get a real knack for MIG welding and want to go to the next level, consider a TIG.
15 This is a TIG (tungsten inert gas) welder. TIG welding requires more skill and patienc
16 Here’s a shot of the typical grinders, sanders, and cutters you’ll need when working with metal and welding. Again, all of these are available from most tool sellers, along with their required supplies such as new grinding wheels, cutoff discs, and sanding discs of various grits. In this area you can either go with electric or air power and be good to go, but on the cutoff wheel we’d recommend an air-powered version for some extra muscle.
16 Here’s a shot of the typical grinders, sanders, and cutters you’ll need when working w

SOURCES
Miller Electric 1635 W. Spencer Street Appleton WI 54912 920-734-9821 www.millerwelds.com	Classic Automotive Restoration Specialists Inc. 8235 Nautical Point Drive Belews Creek NC 27009 336-595-3900 www.classicautomotiverestoration .com
Lincoln Electric 22801 St. Clair Ave Cleveland OH 44117 216-481-8100 www.lincolnelectric.com