MIG welding tips and resources
|Photo courtesy of AlcoTec Wire Corp.|
Motorcycle- and hot rod-building shows on TV have put welding in a very positive light lately. In fact, Jesse James, the star of Discovery Channel's "Monster Garage," was named the American Welding Society (AWS) Welder of the Year because of his contributions to the trade. It's nice to see welding in a good light after seeing it maligned for so long.
Over the years I've had a love/hate relationship with welding. I loved it when work and money were plentiful and the weather was nice. I hated it when there was no work to be found, I was broke, and when I was freezing or sweating my tail off.
Welding gets into your blood. It's fun for both professional and hobby welders, and being a welder is like belonging to a club.
In my fundamental MIG class, people really get fired up about and enjoy welding once they start to get "into the zone." One of my students, Chris Williams, enjoys it so much that he wore his welding hood when he got married (see Figure 1)!
Chris and Peggy Williams' December 2004 Wedding
Although this article mainly is for the welding hobbyist and those just getting into MIG welding, advanced welders also might find the material and reference sites interesting and useful.
Remember that you never can be too safe when welding! In my articles, I sometimes relate mishaps, both my own and other's, so that you can avoid making the same mistakes. I'm not embarrassed to admit (well, maybe sometimes) that I mess up every now and then. Anyone who claims he doesn't might be fooling himself, but not me. As long as we're human, we will make mistakes. I try to teach my high school students that the key is to learn from mistakes and not repeat them. What was it that Gomer said about his Grandma Pyle? "Fool me once, shame on you; fool me twice, shame on me!" Same goes with mistakes: Learn from the first, and don't make it again.
Beware the Juice
I had a nice 110-V MIG machine that I couldn't wait to hook up in my garage. Well, after using it, the dryer wouldn't heat up anymore. I got down on the floor, took off the machine's front plate, and looked at the insides. "Aha! It's just a coincidence. The coil there is broken." As I continued to talk to myself—all proud that I had diagnosed the problem—I pointed to the coil a little too closely and shocked the living bejeebers outta' me! That's right—220 V of pure electricity surged right through my pointer finger.
I jumped up yelling, screaming, hollering, thanking God that I wasn't dead, then went over and unplugged the stupid machine—which I should've done in the first place. Then I lay back down on the floor, pointed, and began to talk to the machine: "You stupid little %$##@* heating coil ..." Again, 220 V of pure electricity went right into my pointer finger. I had unplugged the 110-V washing machine instead of the welding machine! Now I pride myself on safety and a reasonable amount of common sense, but I have to say, it doesn't get much dumber than that.
I have humiliated myself to remind you that when you let your mind wander or get in a hurry, you might find yourself doing something that can hurt you. I should have taken my time and made sure that the machine was unplugged before I even thought about taking off the front plate. Never work on your welding machine unless you knowwhat you are doing. Even if the machine is unplugged, its capacitors can store enough electricity to zap you. Insulate yourself from electricity, because Mr. Electricity is always looking to go to the ground, and he will be happy to use you to get there. As long as you wear gloves (unlike the macho guys on the cable channels), stay dry, and make sure your machine connections are tight and grounded, you'll be all right.
Stay Away From Containers
I often address containers in my articles because I cannot stress enough the dangers of working on or around them. Almost every year I hear that someone has been hurt, maimed, or killed working on some kind of container. Remember, containers can be toxic, explosive, or flammable.
When working on bikes and hot rods, remember the gas tank! All it takes is an errant spark to cause an explosion or flash fire if vapors are present. An empty or partially filled tank is more dangerous than a filled one because of the vapors present in the empty space. A full tank will burn, but it won't explode or flash. If possible, remove the tank before working on the vehicle.
Protect Your Eyes
Be very careful with your eyes. Do not cut or weld without the appropriate eye protection. Make sure you have the proper shade when cutting and welding.
Be sure to read and learn all welding safety procedures. Welding can be a fun, safe hobby as long as you educate yourself and use common sense. Miller Electric's eTraining (see reference list below) is a good resource for basic MIG principles and safety guidelines.
Professor Marty's Top Tips
Years of welding and teaching welding have given me insight into the most often asked questions about MIG welding. The following tips may answer your questions. You'll find additional information in the resources at the end of the article.
- If you're teaching yourself, surf all the Net sites, read all the manuals, and watch all the videos you possibly can. Remember, no one is there to correct you if you are doing something wrong.
- Along with practice, practice, practice, remember safety, safety, safety!
- You can MIG weld mild steel, stainless, and aluminum, although you will need a special adapter for aluminum.
- MIG is great for welding motorcycle frames and race car frames. And although it keeps the heat-affected zone concentrated, remember to be careful with the amount of heat used.
- MIG ain't worth a dang on paint, dirt, rust, oil, and grease.
- Use nozzle dip or antispatter spray to keep your gun nozzle from getting clogged with spatter (molten welding droplets that solidify and stick to the inside of the nozzle, obstructing shielding gas flow).
- Use a pad with cleaner where the wire feeds into the liner to prevent the liner from clogging up with dirt.
- Most solid-steel MIG wire has a tensile strength (ability to resist being pulled apart) of 70,000 lbs. per square inch.
- A good general-use wire diameter for the hobbyist is 0.035 in.
- Make sure your machine is set to direct current electrode positive (DCEP)—what used to be called reverse polarity. Commonly used in MIG welding, DCEP gives the best penetration in steel.
- Remember to use the right amp fuse where you plug in your machine. Make sure your wiring is sufficient to carry the current.
- A 75/25 shielding gas (75 percent Argon / 25 percent carbon dioxide) is perfect for the hobbyist.
- A good general flow rate for your shielding gas is 20 cubic feet per hour (CFH) unless specified otherwise on your regulator.
- Although you cannot have air blowing around because it displaces your shielding gas, make sure you have some ventilation. Do not inhale the shielding gas. Inhaling argon can cause you to wake up dead!
- Put the work clamp as close as possible to the work piece. That way you'll have a better circuit, which will give you a better weld.
- Although most manuals recommend wire stickout (from nozzle to steel) of 1/8-in. to 1/4-in., I recommend using as little stickout as possible. When filling in a big gap or hole, I allow up to 1/2-in. of stickout.
When welding thin gauge, allow more wire stickout—even up to 3/4-in. Use the push, or forehand, method because you don't want very much penetration.
- Forehand welding allows you to see better with shallow penetration. Although difficult to see because of the nozzle, backhand welding is smooth and gives the best penetration.
- Relax your hand and watch the puddle. Watch your travel speed, gun angle, and temperature (heat, or amps, which are controlled by the wire feed speed). The thinner the steel, the faster the travel speed.
- Skip weld—weld a couple of inches at the beginning, middle, end, and then come back—when you want to control distortion. If you weld a long seam all at once, you are likely to warp the steel.
- Make sure you are getting good penetration into the steel.
- Your machine should sound like bacon frying when it is set right on short circuit.
- The more you burn, the more you'll learn. Do it right the first time. Cutting corners usually results in problems that have to be corrected.
- Check around when buying equipment. Prices vary big-time.
- Above all, have fun!
Metallurgy is the study or science of metals, and surgery is cutting, right? Well, after you have passed Miller's eTraining and practiced cutting and welding, at the next cocktail party you can tell people you are a "metallurgical surgeon". They either will nod their heads in awe if they don't know what that is, or if they do, they and you can talk welding all evening long.
Marty's Recommended Resources
Educational Web Links
American Welding Society: http://www.aws.org
Miller's eTraining: http://www.millerwelds.com/education/etraining.html
Lincoln's Educational Resources: https://ssl.lincolnelectric.com/lincoln/apdirect/default.asp
Hobart's Technical Tip Page With Glossary: http://www.hobartwelders.com/techtips.html#mig
ESAB Basic Correspondence Course: http://www.esabna.com/EUWeb/AWTC/Lesson1_1.htm
ESAB MIG Handbook: http://www.esabna.com/EUWeb/MIG_handbook/592mig1_1.htm
Stock Car Racing Technical Article: http://www.stockcarracing.com/techarticles/82101/
I recommend Richard Finch's books on welding. Numerous titles are available. They can be found in bookstores and on the Internet at sites such as www.amazon.com.
Hot Rod Forum: http://www.clubhotrod.com/t8654-15-1.html
Welding Web Forums: http://www.weldingweb.com/archive/index.php/
Projects on the Internet:
(When surfing the Internet, enter the words "steel art," "metal art," and similar terms to find other cool projects.)
Questions for the author can be e-mailed to firstname.lastname@example.org