Figure 5-19.  Gas welding eye shield attached to adjustable  headgear. Figure 5-20.  Torch lighter. flying sparks, and accepts a variety of standard shade and  color lenses. A clear safety glass lens is added in front of the  shaded lens to protect it from damage.  [Figure 5-19] It was standard practice in the past to select a lens shade for  gas welding based on the brightness of flame emitting from  the torch. The darkest shade of lens showing a clear definition  of the work was normally the most desirable. However, when  flux was used for brazing and welding, the torch heat caused  the sodium in the flux to give off a brilliant yellow-orange  flare, hiding a clear view of the weld area and causing many  eye problems.  Various types of lens and colors were tried for periods of time  without much success. It was not until the late 1980s that  TM Technologies developed and patented a new green glass  designed especially for aluminum oxy-fuel welding. It not  only eliminated the sodium orange flare completely, but also  provided the necessary protection from ultraviolet, infrared,  and blue light, and impact to meet the requirements of the  American National Standards Institute (ANSI) Z87-1989  Safety Standards for a special purpose lens. This lens can be  used for welding and brazing all metals using an oxy-fuel torch.  some cases, a suitable rod with a lower melting point helps  to avoid cracks caused by expansion and contraction. Welding rods may be classified as ferrous or nonferrous.  Ferrous rods include carbon and alloy steel rods, as well as  cast-iron rods. Nonferrous rods include brass, aluminum,  magnesium, copper, silver, and their various alloys. Welding rods are manufactured in standard 36-inch lengths  and in diameters from  1 ⁄ 16 -inch to  3 ⁄ 8 -inch. The diameter of the  rod to be used is governed by the thickness of the metals to  be joined. If the rod is too small, it cannot conduct heat away  from the puddle rapidly enough, and a burned hole results.  A rod too large in diameter draws heat away and chills the  puddle, resulting in poor penetration of the joined metal. All  filler rods should be cleaned prior to use. Torch lighters are called friction lighters or flint strikers. The  lighter consists of a file-shaped piece of steel, usually recessed  in a cuplike device, and a replaceable flint, which when drawn  across the steel produces a shower of sparks to light the fuel  gas. An open flame or match should never be used to light a  torch, because accumulated gas may envelop the hand and  when ignited cause a severe burn.  [Figure 5-20]  Setting up acetylene welding equipment in preparation for  welding should be accomplished in a systematic and definite  order to avoid costly damage to equipment and compromising  the safety of personnel.  The use of the proper type of filler rod is very important  for oxy-acetylene welding. This material adds not only  reinforcement to the weld area, but also desired properties to  the finished weld. By selecting the proper rod, tensile strength  or ductility can be secured in a weld. Similarly, the proper rod  can help retain the desired amount of corrosion resistance. In  All cylinders should be stored and transported in the upright  position, especially acetylene cylinders, because they contain  an absorbent material saturated with liquid acetone. If the  cylinder were laid on its side, allowing the acetone to enter  and contaminate the regulator, hose, and torch, fuel starvation  and a resultant flashback in the system could result. If an  acetylene cylinder must be placed on its side for a period of  time, it must be stored in the upright position for at least twice  as long before being used. Gas cylinders should be secured,  usually with a chain, in a permanent location or in a suitable  mobile cart. The cylinder’s protective steel cap should not  be removed until the cylinder is put into service.  Prior to installing the regulator on a gas cylinder, open the  cylinder shutoff valve for an instant to blow out any foreign  material that may be lodged in the outlet. Close the valve and  wipe off the connection with a clean oil-free cloth. Connect  the acetylene pressure regulator to the acetylene cylinder  5-10 Gas Cylinders Regulators Filler Rod Torch Lighters Equipment Setup