Tech - The Basics Of Welding
Tackle your own metal repairs on your vintage Mustang project
So you’ve boned up on all the proper safety precautions, you’ve researched your equipment, and you’ve setup your new machine with some welding wire and shielding gas. You’re ready to melt some metal together right? Hold on a second there skippy; you’ve got more learning to do. Creating a good weld that is safe and securely bonds your work pieces together takes some training and knowledge.
First, you have to know the type of metal you are welding, as well as the thickness of the metal, so you can properly setup your MIG welder’s wire feed speed and voltage to produce the best welds. You also have to determine the best way to approach the work piece (not everything is a straight weld on a work bench), including positioning the MIG gun, electrode extension, and gun travel speed. No two welding jobs are the same. Every time you fire up your welder it is recommended to test your settings on a scrap work piece to ensure your settings are correct. Just assuming your welder is properly set because the job is similar to something you’ve done in the past can mean poor weld penetration, excessive spatter, burn through, or porosity of the weld.
It has been said that applying a good MIG weld sounds like sizzling bacon, and while this is true, it is not something a beginner should rely on by sound alone. During your initial use, and until you are comfortable with your new equipment, it is best to pick up some scrap metal in the thickness you intend to weld (damaged fender from a body shop, some old angle iron brackets, etc.) and practice on these parts, learning what your welder can do and the proper settings, before striking the first arc on those pretty new quarter panels.
After speaking with various welders, pulling from our own experiences, and reviewing the massive amounts of training materials you’ll find on our sources’ websites, we’ve come up with these additional tips to consider before you strike that arc with your new welder.
- Keep the MIG wire feeding mechanism at the right tension and clean of any dirt or grease.
- Some welders prefer to push the gun, others pull, but both methods are correct in specific circumstances. Pushing the gun will give less penetration but a wider bead, while pulling the gun will do the opposite (narrow bead and more penetration).
- Keep the gun tube/liner as straight as possible to minimize wire feed speed issues.
- Use both hands to steady the gun for better looking welds.
- Tack weld pieces first and then finish weld, being sure to move around to prevent heat warpage.
- Use the proper shielding gas. Typically an Argon/CO2 mix is used for thinner steels in automotive work.
- Know your machine’s duty cycle for the settings you are using and let it cool for the proper time frame.
- Don’t let people watch you weld without the proper safety equipment in use on them as well.
A complete safety rig like this Lincoln Electric Ready-Pak offers everything you need to be safe while welding in one convenient package. The kit includes a Viking auto-darkening welding helmet, welding jacket, leather and traditional MIG gloves, safety glasses, and “doo rag.” You can be all set and ready to go for under $300.
Over the years many of us have sourced heavy work gloves for grinding, perhaps even a work jacket, so you might have much of what you need to get started welding safely, except for the welding helmet itself. A nice auto-darkening helmet, like this Viking 2450 series, will fit the bill nicely. Lincoln Electric carries a full line of helmets, including some trick licensed graphics from Chip Foose, Iron Man, Captain America, and others.
While the majority of those reading will be using a MIG welder for panel replacement and light on-car fabrication, if you find yourself making lots of small parts or repairing small items, you may wish to invest in a welding table, like Miller’s Arc Station. The Arc Station provides a secure welding surface with material clamps, yet easily folds out of the way when not in use.
Welding metals together takes knowledge of your machine’s settings, but there are also general rules of thumb to go by for material thickness, type of gas, and wire size. One quick way to get close to the optimum settings is with a welding calculator. You can find them on numerous welding supply sites, and Miller even has an iPhone app to put a calculator right in your pocket.
Thanks to our friends at Lincoln Electric, here’s a visual representation of what a good weld looks like, along with a whole lot of bad welds due to various improper settings and user error. These welds were produced using short circuit transfer mode and a typical weave pattern bead. From left to right: -Proper wire feed speed, voltage, electrical stick out, and gun travel speed -Wire feed speed too slow -Wire feed speed too fast -Electrical stickout too short -Electrical stickout too long -Gun travel speed too slow -Gun travel speed too fast -Not enough gas coverage (low bottle pressure, regulator set too low, etc.
Welding wire comes in several diameters, each of which is capable of welding a range of material thicknesses. As you can see by this chart (courtesy of Miller Electric), .035-inch wire has the greatest range and what you will normally find in most machines at body and fab shops. However, for those just starting out, .030-inch wire is easier to weld on thinner metals like sheetmetal. So if you’re planning on a lot of sheetmetal/panel replacement work, you might want to consider spooling your machine with .030-inch wire.