1. 4
   12
2. 21
   Over 30

While most people might only think of welding with a torch or something like MIG welding, there are numerous kinds of welding, over 30 in fact. Some require electrodes like MIG welding, while others burn fuel like oxyacetylene welding.

1. Electron-Beam Welding
   Energy-Blast Welding
2. Electronic Bond Weld
   Energetic Base Weld

Electron-beam welding uses high-velocity electrons to form a bond between metals. The kinetic energy created by the flow of electrons actually melts the two surfaces and allows them to bond together.

1. Light Blast Weld
   Level Bed Weld
2. Laser Beam Weld
   Linked Bell Weld

A laser beam weld is just what it sounds like, a weld performed with a laser. Unlike many welds, a laser beam weld can be used not just on metal but on thermoplastics as well. Because a laser can be so well focused, this can produce very thin yet very deep welds.

1. The substance being welded is subjected to intense, quick heat.
   The substance being welded is forced together slowly under pressure.
2. The substance being welded is chemically bonded with an acid.
   The substance being welded is subjected to high-frequency vibrations.

Ultrasonic welds are a kind of solid-state weld. A tool is applied to the plastic being welded or, in some cases, even thin metal. It is vibrated so fast, at such a high frequency, that it bonds the two pieces of the weld together thanks to the friction melting them.

1. Relative Strength Welds
   Resistance Spot Welding
2. Reverb Slow Welds
   Running Slot Welding

Resistance spot welding, better known as simply spot welding, bonds metal together with the power of heat caused by resistance to an electrical current. Thin metal is held together under pressure and a current is run through it. The spot is where the current passes melts the metal.

1. General Electric
   General Motors
2. Coca Cola
   Exxon

General Motors installed a massive industrial welding robot on the line back in 1961. Called the Unimate, the enormous arm weighed more than 2 tons and could perform spot welds based on some simple programming.

1. Firm welding
   Space welding
2. Cold welding
   Blank welding

Cold welding is a very bizarre sounding phenomenon that occurs in a vacuum. If two perfectly clean pieces of flat, similar metal come into contact in a vacuum, they will bond together with no heat required. With nothing separating the atoms, they have no reason not to become one thing.

1. Fume plume
   Exhaust burst
2. Fume bloud
   Gas burst

The fume plume is the kind of clever but fairly accurate name for a cloud of fumes coming off a weld. You're going to want to do your best to not breathe this stuff in as it can be quite toxic.

1. 1876
   1903
2. 1915
   1931

Oxygen-acetylene welding was developed in 1903 by French engineers. Pure oxygen allows for an increase in the temperature of the flame, and oxy-acetylene torches could burn at temperatures of over 6,000 degrees.

1. 1957
   1961
2. 1966
   1969

In 1969, Georgi Shonin and Valeri Kubasov from the Soyuz 6 mission became the first humans to ever try their hand at welding in outer space. They used a tool called the Vulkan and made a weld that was about as good as any weld from Earth.

1. Explosion welding
   Expansive welding
2. Energy exchange welding
   Extreme welding

Explosion welding is weirdly just what you think it is: a kind of solid state welding that uses the force of an explosion to force two metals together at incredible speed. It was discovered by accident after WWI when soldiers noticed shrapnel bonded to other kinds of metal.

1. Metal in Grain
   Most Iron Gauge
2. Metal Inert Gas
   Multi-Ion Gas

Metal Inert Gas or MIG welds are a kind of gas metal arc welding. While many years ago welding with oxy-acetylene torches was the norm, arc welding has become much more popular and commonplace.

1. It cleans the metal.
   It's what bonds the metal.
2. It prevents porosity.
   it prevents brittle welds.

Porosity is what happens when the metal in a weld gets contaminated by trapped gas. The weld will look bubbly when it's done and will not be as strong as it should be. The coating on a MIG weld electrode helps prevent this contamination from happening.

1. Electricity
   Burning fuel
2. Friction
   Lasers

Arc welding works with electricity to create heat for the weld. An electrical arc is created between the stick in the welding tool and the metal that is the base of the weld. That arc, which looks to the naked eye like a very bright spark, is what heats the metal to allow the bond.

1. Greeks
   Romans
2. Egyptians
   Celts

Egyptians were considered among the first to develop rudimentary welding techniques. During the Bronze Age, they began melting iron and by around 1,000 BC they had perfected a technique to make solder.

1. Secondary burns from welding
   Inflammation of the eye caused by exposure to bright welds
2. A skin condition caused by prolonged exposure to welding heat
   A condition leading to baldness caused by proximity to welding

Sometimes called arc eye, photokeratitis is a painful inflammation of the eyes caused by exposure to the bright light and radiation from welding that often won't be noticed until it's too late. It's why welders wear goggles.

1. SS Robert E. Peary
   SS David Miller
2. SS Lawson
   SS Archibald

The SS Robert E. Peary was welded together in just over 4 and a half days during a competition in 1942. Over 250,000 separate pieces together weighing more than 14 million pounds were put together in that time.

1. 150 hours
   300 hours
2. 700 hours
   950 hours

You can't buy a NASCAR vehicle off the showroom floor, they need to basically be custom made from the ground up. That means around 950 hours of work go into fabricating and assembling these cars, all with hand welds.

1. Pacemaker
   Insulin pump
2. Artificial limb
   Blood pressure cuff

If you have a pacemaker, you need to be wearing of power sources for some arc welding machines. Evidence has shown that welding machines operate at a frequency that can interfere with pacemakers at a range of about 2 meters.

1. Oxy-acetylene
   MIG
2. Laser
   None of the above

Eye protection should be worn no matter what type of welding you're doing. The amount of shade in the lenses you're wearing can vary depending on how you're welding, but it's never a bad idea to protect your eyes.

1. Titanium Inert Gas
   Tungsten Inert Gas
2. Tempered Inert Gas
   Transposed Inert Gas

Tungsten inert gas uses a non-consumable electrode, unlike MIG welding. In this case, the tungsten electrode is not used up like the thin electrode in MIG welding. It makes for great welds but is slow and requires much more skill to pull off.

1. Red
   Green
2. Black
   Blue

It helps to know what line you're dealing with at a glance so the hoses are color coded. Red is the color for a fuel line, while green is the color of a line carrying oxygen. If you're using an inert gas in something, it probably goes through a black hose.

1. Yes
   Arc-welds only
2. Oxy-acetylene welds only
   No

You don't want to ever use concrete as a backdrop for your welding. Heat from the weld can superheat little gas bubbles in the concrete and literally cause it to explode underneath you.

1. 1000 °C
   4000 °C
2. 3000 °C
   6000 °C

Atomic Hydrogen Welding or AHW is a kind of arc welding that shields tungsten electrodes in hydrogen to produce an incredibly hot flame. The 4000°C it produces is much hotter than something like an acetylene torch, which produces flame about 700 degrees lower.

1. Matches
   Striker
2. Lighter
   Burning splint

A striker is the only safe way to light your torch, creating a spark that ignites the gas. Any direct flame method like matches or a lighter could be too dangerous and result in burns.

1. Nothing
   It will overheat.
2. It won't work at all.
   it will melt through the metal.

Underwater welding units for wet welding are designed specifically to be used in the water. When used outside the water, they run the risk of overheating since the constant exposure to wet conditions isn't there to maintain the temperature.

1. Fillet
   Weave
2. Straight
   Hammer

The metal deposited on a surface while you weld is called the bead. You can create different kinds of beads depending on how you weld. A fillet joins two pieces at an angle while a weave is caused by a side to side motion. There is no such thing as a hammer bead.

1. Metallurgy
   Geology
2. Vulcanology
   Phrenology

The study of metal is called metallurgy. The name comes from alchemy when, back in the day, you would be considered a metallurgist if you could extract metal from minerals. Early examples of that include the smelting of gold.

1. Cotton
   Rayon
2. Leather
   Denim

Synthetic fabrics are always the worst idea for welding unless they're specifically designed to be heat and flame resistant. A flammable fabric or one that can melt puts you at a much greater risk of injury than most natural fibers.

1. Toxic fumes
   Radiation
2. Electrical shock
   All of the above

Welding can be extremely dangerous, and arc welding is no exception. Welders have to be on the lookout for electrical shock, toxic fumes and even UV radiation, not to mention burns, eye damage and various cuts and bruises one could suffer.

1. X-ray welding
   Magnetic pulse welding
2. Phased plasma welding
   Electroslag welding

There's no such thing as phased plasma welding, but the others all exist. X-ray welding is still fairly new and relies on focused X-rays to produce heat for an extremely accurate weld. Magnetic pulse uses electromagnetic radiation, and electroslag is a kind of arc weld.

1. Flux-Cored Arc Welding
   Full Channel Arc Welding
2. Flame Center Alternating Weld
   Flat Core Anterior Weld

Flux-cored arc welding is quite a bit like MIG welding overall, but the difference is in the electrode. Instead of a solid wire like in MIG welding, the FCAW weld uses one that is hollow and filled with flux.

1. Carbon dioxide
   Chlorofluorocarbon
2. Carbon monoxide
   Carbon disulfide

Carbon monoxide gas is what's used to protect the weld during a carbon arc weld. The electrode used in carbon arc welding is a non-consumable electrode as in tungsten inert gas welding.

1. General Metal Arc Welding
   Gas Metal Arc Welding
2. Gas Metal Able Welding
   Graded Metal Arc Welding

Gas metal arc welding is any kind of welding in which an electric arc forms between an electrode of some kind and whatever metal it is that you're trying to weld at that time. The gas part refers to a gs used for shielding, which can come in several varieties.

1. Metal arc polypropinate
   Metal acetylene-propane pyrene
2. Methylacetylene-propadiene propane
   Methylacetylene poly-propane

Methylacetylene-propadiene propane is a kind of gas that is considered a safer and more stable substitute for acetylene gas. interestingly, MAPP is a trademark and the product is no longer produced. Any MAPP in circulation currently is a substitute product.