Welding For Dummies. Steven Robert Farnsworth

extinguishers (shown in Figure 3-2) work on four different kinds of fires:

      ❯❯ Class A: Class A extinguishers take care of any fires that produce ash. These fires usually involve wood, cloth, or paper.

      ❯❯ Class B: Class B fire extinguishers are for fighting fires caused by flammable liquids, such as gasoline, oils, and paints.

      ❯❯

Class C: Electrical fires call for Class C fire extinguishers. Don’t use any water- or foam-based extinguishers on an electric fire, or you put yourself at risk of serious shock.

      ❯❯ Class D: Use Class D extinguishers on metal fires. Combustible metals like magnesium, potassium, and sodium are extremely flammable, and fires based on these materials are very dangerous. Class D extinguishers are best for these fires because the other classes often disperse a metal fire instead of putting it out, and that makes the situation worse.

      You should keep a Class C extinguisher nearby when you’re welding, in case an electrical fire breaks out. I recommend also keeping a Class B on hand for oil fires.

      

In addition to fire extinguishers, keep a water source (a hose, for example) and a bucket of sand nearby when you’re welding. They can come in handy when you need to control ash and metal fires, respectively, without the need for special extinguishers.

      

The best way to avoid needing an extinguisher is to cut down on the flammability of your project in the first place. For example, you may find the need to weld a metal 55-gallon drum. (It’s a common welding task.) If so, take care to ensure that the drum doesn’t have residual flammable materials on the interior. Before welding, be sure to clean the interior with steam or a chemical cleaner.

      FIGURE 3-2: Four classes of fire extinguishers.

Wearing protective clothing

      If you’ve ever thought of yourself getting started on your first welding project wearing a pair of shorts, an old t-shirt, and a pair of flip-flops, think again. If you want to keep your body safe from the hazards of welding – especially burns – you have to always wear appropriate protective clothing.

      Welding produces a huge amount of hot metal sparks and flying slag (molten metal). To keep your skin from being burned, choose clothing made from the right material. One of the best options is 100-percent wool, but it can be difficult to find and is extremely hot. (Some people are also allergic to wool.) I prefer 100-percent cotton, and it’s the most popular material used for welding clothing. The fabric should be thick (because welding rays can penetrate thin fabric and burn your skin like a sunburn) and dark-colored; black and dark blue are good options.

      

Sorry, but you can’t use that old polyester leisure suit from the ’70s when you’re welding. Synthetic fabrics like polyester, nylon, and rayon are unsafe for welding because they can melt and adhere to your skin when they get hot. And that definitely does not promote leisure.

      Before welding, check to see that your clothes are free from oil and anything else flammable. They should also be tight fitting and free from holes and frayed or torn edges. Here are a few more clothing-related details to bear in mind.

      ❯❯ Shirts: Wear long-sleeved shirts only, and tuck your shirttail into your pants. If you wear a shirt with front pockets, make sure they have flaps covering them so that sparks can’t fall down inside. Keep your shirt sleeves rolled down at all times.

      ❯❯ Pants: Make sure your pants cover the tops of your shoes or boots so that sparks can’t get in.

      ❯❯ Gloves: Protect your hands with leather gauntlet gloves. Don’t wear cotton gloves at any time.

      ❯❯ Boots or shoes: Go with leather boots or shoes, and make sure they come up high on your ankle. Leather is the best option because it protects you from the hazards and heat created by the welding process. The tops of the shoes should be smooth so sparks don’t get trapped.

      ❯❯ Hats or beanies: You can buy a welder’s beanie to keep your hair from catching fire – not a bad idea.

      ❯❯ Leather jackets: A full leather jacket protects you from sparks and slag when you’re doing work in unusual positions, but many such jackets are very hot and heavy to wear. If a leather jacket is too hot and uncomfortable, you can buy leather sleeves and bibs only. These items are cooler and more comfortable, but they do leave your back unprotected.

      ❯❯ Leather aprons: These items protect your lap, and I highly recommend wearing one if you plan to sit down while welding.

      ❯❯ Spats: If you’re going to have a large amount of sparks and slag (the waste products that come from the flux) falling at your feet, you may consider getting some spats (shoe covers). Leather spats greatly reduce the risk of burns on your feet and damage to your shoes or boots.

      

Be careful what you have in your pockets when you weld. If you have a cigarette lighter or matches in your pocket during a welding project and a spark gets close enough, it can cause a fire in your pocket.

Watching health hazards: Using a respirator and Material Safety Data Sheets

      

Keep the Material Safety Data Sheets (MSDS) for every chemical and other potentially hazardous material in your welding shop on hand. These sheets describe all the properties of a given substance and include details on potential health hazards. Make certain that you and anyone who enters your welding area know the dangers of the materials on hand.

      If you’re going to be working with metals or other materials that can produce toxic fumes – check your MSDS to be sure – you should wear a respirator. Simply welding or cutting certain materials can cause a welding plume, which is a mixture of dangerous gases, fumes, and smoke, and that’s definitely not the kind of thing you want to inhale if you’re interested in avoiding respiratory problems.

Figure 3-3 shows four types of respirators:

      ❯❯ On the top left, you can see a welder’s mask, which works to keep fumes out of your lungs.

      ❯❯ The mask on the top right has canisters that filter fumes and other hazardous materials while you’re welding. You can get different types of canisters to match the kinds of hazards specific to various welding projects.

      ❯❯ The basic dust mask on the bottom left offers the least amount of protection.

      ❯❯ The mask on the bottom right filters out particulate matter, so it’s a step up from the basic dust mask but doesn’t do much to protect you from harmful chemical fumes.

      FIGURE 3-3: Four different respirator masks.

      

The metals you weld aren’t the only items that can cause harmful fumes – the substances that may coat those metals can also be hazardous. If you suspect that a piece of metal may be coated with paint or another kind of chemical that may generate dangerous fumes when heated up, be sure you remove that substance (with a chemical cleaner or grinder) before you weld.

      In order for a respirator to be completely effective, you need to fit it with the