Welding 101: The Home Welder - Hot Bike Magazine
The business end of the MIG welder is called a gun. Filler wire and shielding gas is fed out of the end of the gun.
A midsized MIG welder from Lincoln Electric that can be adapted to weld aluminum.
TIG welders use a torch to hold the electrode. This one is water-cooled.
Adequate for professional use in light fabrication, the Auto-Set function on this Millermatic 212 Auto-Set MIG welder (approximately $2,000) appeals to beginning welders because it takes the fear out of machine setup. You just set the welding wire size and material thickness and Auto-Set selects the optimal wire feed speed and voltage.
With fewer controls to deal with than most TIG welders, the Diversion 165 ($1,617) from Miller is not only easier to set up but priced right for beginners. it also comes with Welding for Dummies and a DVD on how to set up and operate the machine, along with some basic TIG welding tips.
HIWT has 143 welding booths complete with a welding table and material position holder to practice welding in all positions.
A well-stocked welding store will make your life a lot easier.
Welders ready to try. Ask for a testdrive before you buy. Most stores will work with you to meet your needs.
Get to know the guys at your local store. They can be a valuable resource when starting to weld.
A few years ago on 60 Minutes Jesse James said, "There are two kinds of people in the world, those that can weld and those that can't." You see it every week on cable TV, a fabricator shapes a piece of metal or a couple pieces of metal and then pulls out a MIG or TIG welder, tacks the parts together, and then runs a bead fusing the two pieces together permanently-well hopefully. When they're done it's another perfect part. They make it look easy and after welding bits and pieces of metal together a masterpiece emerges. Can the home hobbyist/enthusiast do the same level of fabrication? Possibly, with the right tools and training almost anyone can create or repair anything. But where do you start? There is a lot to learn, but it's not as daunting as you may think. It does take time and effort though.
What Is Welding?
According to the American Welding Society (AWS), welding is a material joining process which produces coalescence (joining together to form one mass) of materials by heating them to suitable temperatures with or without the application of pressure or by the application of pressure alone and with or without the use of filler (metal added in the welding process) material.
Basically pieces of metal, the base metal, are fixed into position. Heat is applied to melt both pieces of base metal creating the puddle. The welder moves the heat source along the joint continuously melting the base metal and fusing the parts together. In most welding processes, filler metal is added, this replaces the base metal used in the puddle and increases joint strength. Filler metal when properly added to the puddle creates the weld bead.
Welding processes fall into several general groups, such as arc welding, brazing, oxyfuel gas welding, resistance welding, and solid state welding. And within these groups are more specific processes, such as gas metal arc, plasma arc, dip brazing, pressure gas welding, percussion welding, friction welding, and many more.
However, walk into any motorcycle shop and the majority of the time you'll see a Metal Inert Gas (MIG) welder or Tungsten Inert Gas (TIG) welder close by. MIG and TIG both fall into the general arc-welding group. Arc welding utilizes the combination of an electrode and a welding power supply creating a direct or alternating current to create an arc between the electrode and base materials. The arc generates the heat to fuse the base materials together. For the home shop/do-it-yourselfer, both MIG and TIG welders are available to connect to your household 115V outlet, but with these machines the thickness of material that can be welded in a single pass will be limited due to their lower power output. However, if your shop or garage is wired for 230, you'll be able to increase your welding capabilities/materials thickness.
All of the welding processes require some type of shielding to protect the weld puddle from atmospheric contamination. One type of contamination is hydrogen embrittlement, in which the welded material becomes brittle and can severely weaken or fracture the weld due to exposure to hydrogen.
Shielding is done several ways, two of the most common are flux and gas. Flux is applied to the filler rod before welding or it's a coating on the filler rod. There are also paste fluxes that are applied to the base metal. Shielding gas is an inert (nonreactive) gas that is flooded around the weld puddle to protect it. Both MIG and TIG use shielding gas.
Gas Metal Arc Welding (GMAW/MIG)
MIG welding is a process in which an arc is created between a continuously fed filler metal (a wire electrode) and the part being welded. The electrode and shielding gas are fed through the MIG gun. The electrode and shielding gas are both consumables. MIG welders are very popular and for good reason. MIG welders are best suited for indoor use since they use shielding gas to protect the weld. However, if you are going to be welding outdoors where the shielding gas can be blown away as you weld, a variation known as Flux Cored Arc Welding can be utilized. With Flux Core the wire has flux material inside the core of the welding wire, thus it doesn't need shielding gas. Some of the benefits of MIG welding is that it's easy to learn, you have better control on thin materials, it's useful for awkward/out-of-position welding, deep penetration for welding thick sections, you can use the same power source for solid and flux-core wire welding, travel speed, and deposition rates can be higher than TIG for greater speed and efficiency.
Gas Tungsten Arc Welding (GTAW/TIG)
TIG welding is a process in which an arc is created between a nonconsumable tungsten electrode and the parts being welded. An inert gas is used to protect the weld, which is fed through the TIG torch. A foot pedal or fingertip controller is used to control the heat. A filler material is not always needed but when it is, it is fed by hand. With the right TIG equipment you can weld anything. This includes steel, aluminum, stainless steel, titanium, magnesium, and more. TIG gives the welder the most control over the welding process. Most TIG power sources can also be used for stick welding. While TIG is much more versatile in weldable materials than MIG and produces nice-looking welds when done correctly, it is also more difficult to master. Using a tungsten electrode to support the arc, a foot pedal to control heat, filler metal added only when needed, the TIG welder can create the best quality welds but requires more coordination. The shielding gas used is usually argon. Tungsten electrodes are alloyed with various precious metals depending on the base metal being welded. TIG welding machines can be changed from DC both positive and negative ground to AC current quickly. DC current is used for steel and AC is used for aluminum. The benefits of TIG welding are that you can weld more metals and alloys than MIG, it creates clean high-quality welds when weld appearances matter, and welds can be made in all positions. TIG Welders can a bit pricier, but once again you have a broader range of material that can be welded. Miller offers its Diversion 180 AC/DC TIG welder that can be used off both 115V or 230V input power for about $2,150.
There are a number of outlets for training. We recommend training before buying equipment. This will allow you to gauge how much skill and commitment you have. By going to a training class you'll get the opportunity to try different welding processes and equipment. This will help you decide before you purchase if welding is for you. Welding is like riding a bicycle, you never forget how. You may not be as smooth if you haven't welded in a few months, but with a little practice, you should be able to produce good quality results.
The fastest way to becoming a proficient welder is to attend formal training. A number of very good welders started with a friend showing them the basics, but if you're looking to speed up the learning curve, formal training is the answer. There are a number of training options. By taking a class or two you may find you're a natural at welding or it's something you'll never master, without making a large investment.
The local vocational schools may offer classes. We've found it pays to shop vocational schools. The school closest to us offers a basic welding class with 76 hours of training in gas and arc welding for $732 plus textbook. This school also has a Level II class with 100 hours of training for $975. That's 176 hours of training for $1,707.
The vocational school in the next county has welding classes broken out by process that gives the student Gas: 48 hours of training for $285, MIG: 32 hours for $216, Stick: 64 hours for $374, and TIG: 48 hours for $285. That's 192 hours of training for $1,160. The benefit here, besides cost, is you pick the processes you want to learn.
Also there are schools that cater to the welding professional. One of the oldest and largest is the Hobart Institute of Welding Technology in Troy, Ohio. With 143 welding booths and 18 full-time instructors, it is one of the best training facilities in the country. Its classes average two weeks for about $800 and are process or career specific.
Another is the Lincoln Electric Welding School in Cleveland. Its classes average one to two weeks and cost about $350 per week.
There are a number of very good books that provide a basic understanding of welding. Two of our favorites are both by Richard Finch, Welder's Handbook and Performance Welding. Both of these are very good reads and for referencing, when you haven't welded something in a while.
Buying welding equipment is going to take a very serious assessment of your welding needs. If you buy equipment that is underpowered, you'll be frustrated forever. On the other hand, if you buy a welder that is more than you'll ever need, you end up wasting money that could be spent on your projects. Finding a balance gives you the best of both worlds.
Where to buy can be a tough decision. The Internet has bargains galore, but how much follow-up do you get if there's a problem? When buying equipment, we looked at five welding suppliers in the area plus two from the Internet. In the end, we purchased from one of the locals. While its price was slightly higher, the value it provides by being local is well worth the little more spent. This has proven to be a very beneficial relationship. Whenever there is something difficult to weld, they are always ready to help.
In upcoming issues we'll look at the two most popular processes for motorcycle work, TIG and MIG, in greater detail.
A brief comparison of common welding processes-Miller Electric Mfg.
|Type of metal that can be welded||Steel, stainless and aluminum||All weldable metals|
|Metal thickness||24 gauge (.025") and up||.010" and up|
|Welding speed||Very fast||Very slow|
|Practice time required to be proficient||Low||Moderate-high|
|Purchase price for home-use units||Moderate-high||Moderate-high|