Steven Robert Farnsworth - Welding For Dummies

Aluminum conducts heat about five times better than steel, and interestingly, it doesn’t change color when you heat it up. (Steel, of course, turns all kinds of different colors as you heat it up to different temperatures.) It weighs about one-third as much as steel.

Pure aluminum is a popular choice for welders, but many different aluminum alloys have also been developed. A classification system of four-digit numbers has been created to identify the various aluminum alloys. The first digit is the really critical one because it tells you what is included (other than aluminum, of course) in the alloy. Here are the details:

1XXX: Unalloyed aluminums made up of at least 99 percent pure aluminum

2XXX: Copper

3XXX: Manganese

4XXX: Silicon

5XXX: Magnesium

6XXX: Silicon and magnesium

7XXX: Zinc

8XXX: Other materials (tin is one example)

The two types of aluminum you’ll probably weld most often are pure aluminum and aluminum alloy 3003.

Recycle your old aluminum! Almost two-thirds of the aluminum used today has been recycled, and that’s the environmentally responsible thing to do.

If you ask me, welding aluminum isn’t any more difficult or problematic than welding steel. It can take some getting used to, but after you have the hang of it, you can weld aluminum quickly and efficiently by using any one of the three major arc welding methods: stick, tig, and mig.

My first choice for welding aluminum is always tig welding. You need to use alternating current (AC) with continuous high frequency to get the best results. (If those terms don’t make any sense, flip over to Chapters 7and 8for more information on tig welding.) And as with all other tig welding endeavors, make sure you select the right tungsten electrode and shielding gas for the job.

If you’re going to be welding thicker pieces of aluminum, consider going with mig welding. As with stainless steel (see “ Going with Stainless Steel” earlier in the chapter), aluminum can take a long time to weld if you’re working with thick pieces, and mig welding makes the process go faster. Be sure to keep your electrode wire clean, use a 30-degree leading travel angle, and go with pure argon for your shielding gas. (If those details are Greek to you, check out Chapters 9and 10.)

So what about using stick welding for aluminum? Well, it can be done, but I wouldn’t recommend it if you can go with tig or mig instead. Not many stick welding electrodes are available for working with aluminum, and maintaining good arc stability is tough. On top of that, you have to fight a constant battle to make completely sure that you keep the covering on the electrode extremely clean and dry, or you’re sunk. Bottom line: Avoid stick welding aluminum unless you simply have to do it.

You can do a whole lot of welding with only steel, stainless steel, and aluminum, but you’ll inevitably want to branch out a little and work on some less commonly welded metals. Here’s a quick rundown of some of those metals, and you can find more information on them sprinkled throughout the other chapters of the book.

Copper and copper-based alloysUsed for: Plumbing, electrical products, roofing, and as an additive to gold and silver to increase the strength of jewelry.Welding process: You can use mig or tig welding for copper and copper-based alloys. Mig welding works in all positions and it’s especially useful for thicker pieces of copper. If you use mig for welding copper, be sure you use direct current electrode positive (DC+). Go with tig if you want to weld thinner pieces of copper — I recommend using direct current electrode negative (DC–).

MagnesiumUsed for: An alloy in steel. Makes steel resistant to abrasion, so it’s perfect for rock crushers, grinding tools, grinding mills, and so on.Welding process: Use tig for welding thin pieces of magnesium-based alloys; use mig if the pieces are thicker. Some magnesium-based alloys have high levels of zinc in them. Avoid welding those alloys if at all possible because it’s extremely hard to keep them from cracking.

Nickel-based alloysUsed for: An alloy in stainless steel. Nickel in the 200 and 300 series stainless steels is the most resistant to corrosion.Welding process: You can use any of the big three arc welding methods for welding nickel-based alloys. Stick welding gives you a weld that’s stronger than the base metal. (That’s good!) Tig welding a nickel-based alloy involves using a 2 percent thoriated tungsten electrode and argon as your shielding gas. You can tig weld a nickel-based alloy in any position. (If some of those terms look a little wacky to you, flip over to Chapter 7for some gory tig welding details.) Finally, if you’re going to be mig welding a nickel-based alloy, plan to use a 50/50 mix of argon and helium for your shielding gas. Like tig, you can mig weld these alloys in any position.

You may think it sounds crazy, but you can definitely weld precious metals like gold, silver, and platinum. Gold can be soldered (welded at a temperature below 840 degrees Fahrenheit) or brazed (welded at a temperature above 840 degrees Fahrenheit), and I recommend doing so with a gas torch — check out Chapter 13for more on brazing and soldering. The same goes for silver. Platinum is a little different; oxyfuel (see Chapter 11) and tig are your best bets when welding platinum. Oh, and you may want to be sure you have a good lock on your welding shop before you start welding metals that cost thousands of dollars per ounce!

Chapter 3

IN THIS CHAPTER

Making sure you have the right safety gear

Understanding basic safety rules for welding

Knowing how to prepare for and handle accidents and injuries

What’s the most important aspect of welding? The answer is simple: safety. What good does a beautiful weld and a job well done do you if you’ve hurt yourself (or others) in the process?

Many dangerous elements make up any welding operation. You use massive amounts of electricity to join metals (which are often sharp and heavy) through melting. You’re constantly at risk for electric shock, serious eye injuries, and burns. It’s not exactly a pillow fight, is it?

You can’t change the basic elements that make welding dangerous, but you can (and should, without fail) take every precaution to make sure your welding projects are as safe as possible. Your approach to welding safety should be complete and relentless; just one careless move or lack of safety preparation can result in serious injury or death.

In this chapter, I cover all the aspects of welding safety that you need to understand and remember when you get started as a welder. As I mention many times throughout this book, this chapter is really the most important one, and I hope you read it carefully and take its information to heart.

Welding safety is no accident! Be sure to take the precautions necessary to ensure your safety and the safety of those around you. You also need to make sure anyone who comes near your welding projects is aware of proper welding safety practices so that they can help keep themselves safe as well.