Torching and welding: Fashion trends in molten metal

Jan. 1, 2020
Recent innovations make the welder's life on the shop floor more productive and enjoyable. Smooth out the bumps in your work flow.

Recent innovations make the welder's life on the shop floor more productive and enjoyable. Smooth out the bumps in your work flow.

For the collision repair industry, welding is the primary way to make fast, strong and versatile bonds on steel and aluminum parts. Whether replacing quarter panels or various skins, making repairs to subframes or floors, fabbing up a bracket or making a quick tack to make a more effective pull, welding is one of the routine activities that autobody repairs require. There are four main welding processes. The most popular workhorse in collision work is the MIG, or GMAW machine, also known as a “wire-feed” welder. These have been around the shops since the mid-1970s, presently reaching a pinnacle of usefulness and design perfection. Second on the list is the TIG machine, ideal for accurate, detailed construction and repairs, but it requires more cleanliness, has more parts to maintain and takes longer to make the same weld than the MIG does. Years ago, before the MIG became popular in collision repair shops, craftsmen used either the electric stick welder in AC or DC configurations or the oxyacetylene torch. The torch was the mainstay for welding steel and aluminum, as well as for brazing, soldering and making hot shrinks in lumpy panels. With the advent of the stud guns and the spot-weld pullers, however, the hot shrinks are not made with the torch much anymore, and brazing and soldering have been replaced by the MIG and plastic filler, respectively.

So what are the latest fashion trends in the welding marketplace? Let’s take a peek at some of the bells and whistles offered for the welding environment. The machines are taken on first, with helmets, filter plates, fillers and accessories coming after.

The Machines

Since you pretty much have to take the vehicle apart first in order to weld it later, we get to enjoy some organized destruction. One of the fun aspects of this—for me anyway—is the plasma cutter. It counts as a machine and not as a saw, grinder, shear or panel ripper, so I feel it fits right in to our discussion of welding-related equipment. Early versions of the plasma torch were available with inert gas only. Because the cost of helium, argon and nitrogen are more than shop-grade compressed air, these machines were relegated to high-end industry for cutting stainless and hard steels and other such big-buck products. The CO2 models came later making the price a little more bearable, and finally, in the early 1980s, some companies offered shop air models, running clean, filtered, dry air at 90 psi. The prices have dropped considerably, historically from about $3,000, down to $600 nowadays for a machine that will do 11⁄2” plate steel. The advantages are that they will now easily cut through painted steel avoiding sawing or grinding, but either way you will have dirty air to watch out for.

One neat thing with plasma is that no preheat is required to start the cut, but the disadvantage is that one mere blip of the button instantly whacks a clean hole through anything electrically conductive. Most machines can be set to two or three selections of metal thickness, which saves on those tender plasma torch parts known as “consumables.” The plasma cutter can be a suitcase-sized portable package weighing a few pounds up to a rolling powerhouse that will do one-inch stainless in the bat of an eye. Many small portables now run on 110V with larger ones using 220V single phase, and can follow a straight edge or a curved pattern with nice precision and very little slag on the cut edge.

Beware of cutting aluminum with plasma, however, as the cut edge develops micro-cracks that can travel into the sheet, unless trimmed back with a shear to a distance of 3X metal thickness, or simply welded full length. Test a plasma-cut edge with a pair of snips and see if the aluminum shatters when you try to whisker off a thin section. The torch for an old plasma cutter can simply be replaced with a more ergonomic late-model one that uses longer-life and better-performing consumable parts, such as swirl rings, tips and electrodes. The high frequency used to start plasma and welding machines can interfere with computers so manufacturers have responded by using digital inverters that can offer variable-start modes to avoid using the high frequency. These inverters also offer more consistent arc control for a fine kerf and minimal slag.

GMAW (MIG) and GTAW (TIG) Welders

Smooth reliable arc starts on thin sheet are a routine experience with the new inverter technology found on every electric welding machine—MIG, TIG, and stick. While MIG is rapidly achieving a high quality level, it simply cannot make the fine, accurate welds that the TIG can, though its capabilities are indeed significant. Unknown to many of us, shops around the country are having trouble with “dirty power”—power line feeds that have significant fluctuations in voltage. These fluctuations bollix not only the office computers, but cause big headaches for the unsuspecting technician trying to stitch a front end back together down on the shop floor. Welding manufacturers have now specifically addressed this with incredibly efficient inverter designs that not only draw fewer amps on the primary side and enable longer welding leads on the secondary side, but weld with a rock-steady arc all the time. Voltage spikes and voltage drops large enough to cause brownouts should no longer be the reason for erratic and unpredictable MIG and TIG weld performance. These new MIG machines also have digital programming for repeatable welds, hot starts, and feature additional settings for allowing various types of welding applications. With all of this marvelous technology now packed in small boxes, most of the in-shop repair welds should duplicate factory production appearance and performance.

MIG torches are now much more ergonomic and easy to control for smooth wire flows, and can have adjustable triggers for gloved hands. The spool guns for aluminum welding are now lighter and handier than ever, paring the weight down to 22 oz. in some models. Some manufacturers allow for a simple plug-in feature that eases changing torches and guns, and one company has even added a thoughtful 110V receptacle to the back of their machine to save you from having to drag out a separate extension cord for the shop light or grinder.

Helmets

The large-view 4 in. by 5 in. filter plate is becoming very popular, with the expanded field of vision enhancing the user’s safety and mobility. Automatic flip up and auto-darkening plates are now available that move completely out of the line of sight for non-welding tasks such as weld-prep, alignment, grinding and cleanup jobs, saving many hat changes in mid-cycle. Built-in respirator helmet models can actually offer a positive atmosphere of filtered air that is significantly cleaner inside the helmet than is found in the shop air outside the helmet. This might be an alternative to wearing a respirator under the hood and then having to find clearance for it when the lid is down.

Filter plates

New to the electric welding helmet filter plate line are those that now allow adjustment of sensitivity from 10.5 down to a 2.5 shade for grinding processes. Only slightly darker than clear, this shade enables the wearer to see and to be protected against flying steel grit during post-weld cleanup operations, which saves much time by not requiring a change of headgear. New adjustable delay features allow for either a longer dark-to-light recovery time for big molten pools, or a rapid recovery setting for making a quick series of tacks or skip welds on thin sheet. New sensitivity settings now allow for a smaller amp-arc trigger to darken against small/tiny arc flashes and conversely have higher settings for heavy current arcs on thick sections. The arc response or switching times are becoming very fast, and on some products are down to less than 1/10,000th of a second—a huge increase in performance in just five years’ time. Additionally, for the visible “flare” that the welding arc sometimes produces, there are a few rare filter plates that will “see” through it, offering a bright, clean view of the weld zone, which can be very helpful when using flux-cored fillers or when welding certain metals.

Filler wire

Traditionally, the ideal filler for welding steel body sheet was ER70S2, even though the manufacturers called it by their own special names. Recently though, ER70S6 has come to the forefront and surpasses the old S2 in many ways, including penetration, appearance and smoothness. It is fine for the oxyacetylene torch and for the TIG, too. Do not let the copper coating give you any trouble, as you can simply whisk it off with steel wool prior to welding. Ideal thicknesses are .023 and .030 diameter. 

Gas

The old designation for the best inert gas mix for MIG welding was called “gold gas” and it is still the tops in performance, though it is now specified simply by the ratio, C25 (75 percent argon, 25 percent CO2). It runs smooth with good hot starts and nice penetration.

Abrasives

No discussion of welding supplies is complete without a mention of abrasives for cleanup. Many manufacturers have redesigned the old flap wheel into a formidable metal shaping tool. The durability and consistency of the backing has greatly improved and the abrasive grit has as well. Contoured wheels are now available that encourage nice, rapid finishing of the welded parts. The old style hard wheels are now contoured as well, making finish work as precise as the actual welding.

Have fun shopping and make the next job the best yet!

About the Author

Kent White

Kent White achieved master technician, metalman status at Harrah's Auto Collection in 1976. His metalwork appears on many high-end collector classics, vintage racecars, and aircraft around the world. He instructs metalworking, develops tools, publishes metalwork training films, writes, and bangs on metal.

Sponsored Recommendations

Best Body Shop and the 360-Degree-Concept

Spanesi ‘360-Degree-Concept’ Enables Kansas Body Shop to Complete High-Quality Repairs

How Fender Bender Operator of the Year, Morrow Collision Center, Achieves Their Spot-On Measurements

Learn how Fender Bender Operator of the Year, Morrison Collision Center, equipped their new collision facility with “sleek and modern” equipment and tools from Spanesi Americas...

ADAS Applications: What They Are & What They Do

Learn how ADAS utilizes sensors such as radar, sonar, lidar and cameras to perceive the world around the vehicle, and either provide critical information to the driver or take...

Banking on Bigger Profits with a Heavy-Duty Truck Paint Booth

The addition of a heavy-duty paint booth for oversized trucks & vehicles can open the door to new or expanded service opportunities.