Oxy-acetylene torch

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Introduction[edit | edit source]

This Wiki page contains information on the safety equipment, set-up, use, and shut-down associated with an oxy-acetylene cutting torch. There is enough information here for a person with zero prior knowledge of this tool to safely and effectively use the torch to cut through thick metal.

Safety Equipment[edit | edit source]

Safety glasses and welding goggles[edit | edit source]

First and foremost, no operation of the torch should be done without the proper eye protection. Welding goggles with Ultraviolet and infrared filtering lenses should be worn at all times during operation of the torch. These lenses range in darkness from #1-#14, #14 being the darkest. For oxy-acetylene cutting specifically, lenses between a #4 and #6 should be used. Regular safety glasses also need to be worn at all times in the shop.

Protective Clothing[edit | edit source]

Preferred Clothing
  • features covered pockets
  • does not have cuffs ,folds or large wrinkles
  • A welders cap or a hat may be work to protect the hair from catching sparks or getting dirty
  • Thin, tight cuffed leather gloves can be work for light duty jobs, but thick welding gloves should be used for jobs requiring more heat such as thick metals or long cuts

--Clothing with open necklines, open pockets, lots of wrinkles or cuffs may catch flying sparks or hot metal and is therefor dangerous for this operation.

Using the Fume Ventilation[edit | edit source]

  • TURN ON the fume ventilation whenever performing a process that creates excessive fumes in the welding area.
These processes include oxy-acetylene cutting or welding, Mig and Tig welding, plazma cutting and possibly using the oven.
  • The switch for the veltilation system is located on the pillar on the right hand side of the wall as you walk towards the sink and into the welding area.
See Figure 1(a) and Figure 1(b) for location
Figure 1(a)
Figure 1(b))

Preparing the Cutting Torch[edit | edit source]

  • The torch will go onto the opposite ends of the hoses from the tanks.
  • With the torch laying flat on the table as shown below in Fig. 2(a) the oxygen valve is on the right, and the acetylene valve is on the left. The cutting oxygen valve is near the top of the torch handle, near the cutting oxygen lever.
Figure 2(a)

Important:The Oxygen side of the torch has right-handed threads(right turn tighten), and can only attach to the oxygen(green) hose. The Acetylene side of torch is opposite,(left turn tighten) and therefore must be attached to the fuel(red) hose.
  • Refer below to Figure 2(b) for torch tip sizes, change the cutting tip if needed using a wrench to remove the old tip and install the new size.
Figure 2(b) Torch tip sizes, Pressures Table

  • Make sure the holes in the cutting torch tip are clean,
Clean with a broaching tool that can be found in the welding supplied cabinet, by inserting the appropriate size pins into the cutting torch tip holes.
  • Lastly, make sure all of the torch valves are closed before turning on either the fuel or the oxygen.

Preparing the Oxygen and Acetylene Gas Tanks[edit | edit source]

Now with all of the proper safety gear on and the cutting torch prepared, the oxyacetylene cutting outfit can be assembled if it is not already.

Procedure[edit | edit source]

Make sure the oxyacetylene cart and bottles are in a stable and secure position at all times see below figure 3(a).
Figure 3(a)

Throughout procedure, be inspecting fittings, hoses and other equipment for damage, and notify the shop manager if equipment is worn or broken.
  • If there are no hoses connected to the gas bottles, clear any debris inside the valve openings by quickly and briefly opening then closing the top valve no more than 1/4 turn. Make sure there are no people in the line of the open valves and that zero flames are present in the area.
  • With the top valve closed, attach a pressure regulator to the gas cylinder see below Figure 3(b). Start the threads by hand initially, then tightening them with a correct size wrench. Do Not OVER Tighten
Important:The Oxygen regulator has right-handed threads(right turn tighten), and can only be installed on oxygen cylinders. Fuel Cylinders and regulators are the opposite(left turn tighten) and therefore can not be interchanged.
Figure 3(b)
  • When connecting the hoses, red is the fuel line and has left-handed threads like its regulator see below Figure 3(c). The oxygen hose is green and like the oxygen regulator, has right-handed threads see below Figure 3(d).
Picture Picture

Figure 3(c) Acetylene red hose
Figure 3(d) oxygen green hose

Turning on the Oxygen and Acetylene Gas[edit | edit source]

Nr. Picture Explanation

Figure 4(a) For oxygen
Figure 4(b) For acetylene
Fully Close the regulators for both cylinders by turning the adjustment screws left(counter-clockwise) until they feel loose, but stop before they fall out completely. Regulators can burst when exposed to sudden increases in pressure so stand to one side of the regulators when opening the tank valves.
Nr. Picture Explanation
Figure 4(c) Acetylene
SLOWLY open the acetylene cylinder valve by turning it until it is 1/4-1/2 turn out. This is plenty of fuel flow for most cutting operations.
Figure 4(d) Oxygen
SLOWLY open the oxygen cylinder until it is fully opened see below Figure 3(d), so that it will not leak. The correct oxygen working pressure can be seen in the table in the torch operation section.

Igniting and Setting Up the Flame[edit | edit source]

Nr. Picture Explanation
Figure 5(a)
Open the acetylene torch valve 1/16 turn see below Figure 5(a)
Figure 5(b).
Light the preheating flames with a spark lighter. See Figure 5(b). All flames should light at the same time. If all the flames do not light, shut down the torch and clean any dirty orifices

Figure 5(c).Acetylene Burning in Atmosphere Open fuel gas valve until smoke clears from flame.
Continue opening the acetylene torch valve until the smoking stops. The flame must remain in contact in contact with the end of the tip. See Figure 5(c).
Figure 5(d). Carburizing Flame (Excess acetylene with oxygen). Preheat flames required more oxygen.
Open the oxygen torch valve until a neutral flame is obtained. See Figure 5(d). The cutting oxygen valve must be closed during this adjustment
Figure 5(e). Neutral Flame (Acetylene with oxygen) Temperature 5589°F (3067°C), Proper preheat adjustment for cutting.
Open the cutting oxygen valve (lever). The preheating flames should remain neutral. See Figure 5(e). If a carburizing flame is obtained, open the torch oxygen valve a little more. Continue to adjust until feather will disappear and neutral preheating flames remain while the cutting oxygen valve is open.

Making the Cut[edit | edit source]

Securing The Work Piece[edit | edit source]

  • Use the vice on the welding table in the machine shop,the c-clamps or vise grips in the welding cabinets to secure your work piece to the welding table. See below Figure 6(a)
Figure 6(a) c-clamps

Torch Position[edit | edit source]

Hold the torch pointed toward the material about 1/16th inch away. Use a slight 5-20 Deg. angle in direction of the cut, as if you are pushing the cut with the flame. See below Figure 6(b)
Figure 6(b) Angle position of the tip

  • For instance, if you are cutting left to right, tilt the torch back (to the left)
  • The thicker the metal you are cutting the less of an angle(closer to vertical), you want to use so that the heat gets down through the material more quickly.

Cutting[edit | edit source]

  • Hold the torch flame at the desired beginning of the cut until it glows redish/orange. See below Figure 7(a)
Figure 7(a)

  • To begin the cut, press the cutting oxygen lever until the cut has made it through the metal then slowly move along the cut line. See below Figure 7(b)
Figure 7(b)

to see what some incorrect cuts look like, see Fig. 22-8 on pg. 262 of the Welding Technology Fundamentals Handbook in the welding cabinets in the machine shop.
  • Continue the cut until the free piece has fallen away from the clamped piece or until the cut is finished and quickly remove the flame of the torch from the work piece. See below Figure 7(c)
Figure 7(c)

Be careful not to point the torch towards any by standers when removing the flame from the work piece.

Shut-Down and Clean up of Equipment[edit | edit source]

Turning of Cutting Torch[edit | edit source]

  1. After completing the cut and removing the flame from the work piece, you will then close the cutting oxygen valve all the way.
  2. Next, close the acetylene valve all of the way and the flame should extinguish.
  3. Securely close both valves on top of the tanks
  4. Place the torch securely on a table, away from anything flammable as the tip will be very hot.

Disassembly of Cutting Outfit[edit | edit source]

  1. After the torch has cooled, the gas lines need to be drained.
  2. With the tank valves closed, open the acetylene valve and the cutting oxygen valve until the working pressure meters read zero on both tanks, then re-close the torch valves.
  3. back out the regulator adjusting screws (working pressure) until they feel lose, but stop before they fall out.
  4. Remove the torch from the hoses and place it in the left side welding cabinets with the other oxy-acetylene torch tips.
  5. Wind up the hoses and place the tanks and cart in the corner of the welding booth in the machine shop.

Work Space Clean Up[edit | edit source]

  • If there are pieces that are still hot from being worked on, leave then clamped in the vice or on the welding table with the HOT sign in a visible position near the work piece. See below figure 8(a)
Make sure to return to throw away any scrap metal that was cooling off, and to take your work with you.
Figure 8(a)

  • Sweep off the welding table and floor in the welding area.
  • Make Sure to shut off the fume vents when you are done in the welding area.