How To Set Up an Oxy-Acetylene Welding Torch Introduction

These instructions explain how to safely set up an Oxy-Acetylene welding torch, which may be used to heat, weld, solder, braze, and cut metal. Before you begin, make sure you have access to Oxy-Acetylene tanks, that your lines are attached, and that your working environment is dry, well-ventilated, well-lighted, and free of anything flammable, including other gases, paper, diesel/gasoline fuel, and lubricants.

The following guide will explain how to use regulators, connect gas supplies, and safely light the torch flame.

Important Warnings Before Beginning 

1. Do not weld near anything flammable, including other gases, paper, fuel, or lubricants. Explosion, injury, or death may occur.
2. Make sure your work environment is well ventilated. Improper ventilation may cause fire, explosion, or respiratory distress.
3. Make sure your Oxygen and Acetylene tanks are secured with a chain to a cylinder cart, wall, workbench, or post. Injury or death may occur.
4. Make sure that your Oxy-Acetylene tanks have been in an upright position for at least four hours before use. Only use and store in the vertical position. Injury or death may occur.
5. Make sure you wear proper protective clothing–a bib or apron suitable for welding, leather gloves, and shade 5 eye protection–to prevent burns, injuries, and vision loss.

Equipment and Supplies 

• Oxygen cylinder
• Acetylene cylinder
• Oxygen regulator
• Acetylene regulator
• Oxygen and acetylene hoses
• Torch
• Torch tip
• Tip cleaner
• Wrenches for hose connections
• Pliers
• Leather welding gloves
• Striker
• Shade 5 welding goggles

Attaching Regulators 

Step 1: Secure oxygen and acetylene cylinders in an upright position

• • Make sure both cylinders are chained to a cylinder cart, workbench, wall, or post. Cylinders should not be able to be knocked or pulled over.

*WARNING: Cylinders should only be stored and used in a vertical position.

Step 2: Crack the valves of dust or dirt

• • Stand with the outlet facing away from your body and open the valve ¼ turn, very quickly, then close it.
  • Crack one cylinder at a time (this will prevent debris from entering other parts of the torch and causing hazards.

*WARNING: Never crack the valves near other welding work, sparks, or flames. Never stand in front of the outlet while cracking it.

Step 3: Connect the oxygen and acetylene regulators to their cylinders.

• • These regulators are gauges that allow you to see how much pressure you have while welding.
    • Note: If the threads on your cylinders and regulators don’t match, visit your local welding supply store for adaptors.

Step 4: Tighten the nuts of the regulator connection with a wrench.

• • Do not assume that hand tight is good enough. Use only a wrench with a fixed opening (not an adjustable wrench) that is designed for welding tools. You can buy these from a welding supplier.
    • Note: If you need to adjust the nut after the cylinder has been opened and used, make sure to close the cylinder valve before tightening or loosening the nut.

Step 5: Rotate the pressure-adjusting screw to the left until it turns freely.

• • Do this for both the oxygen and the acetylene regulators.
    • Turning the screw counterclockwise releases pressure from the spring in the regulator.
    • When the screw turns freely, it will move with a light touch, no pressure will be necessary.

Step 6: Crack the valves again; open the oxygen and acetylene valves slowly, one at a time.

• • Open the valves very slowly and watch to make sure the pressure gauge stops while you pause.

*WARNINGS:

• • • Do not stand in front of the valves!
    • Never open the Acetylene valve more than one and a half turns.
    • Leave the wrench on the acetylene valve while cracking it, in case you need to make an emergency off. 

Connecting Gas Supplies 

Step 7: Connect welding hoses, torch, and torch tip.

• • Attach the oxygen hose to the oxygen regulator and to the torch.
  • Attach the Acetylene hose to the acetylene regulator and to the torch.
  • Attach your torch tip to your torch, after making sure your tip is clean.
  • Double check your connections.
    • Note: Oxygen hoses are green, while acetylene hoses are red. Never interchange the two!

*WARNINGS:

• • • Never try to patch a hose–if you notice a defect, replace it as soon as possible.
    • Always use hoses specific to welding. 
    • Never use oil or grease on hoses–all of the connections are metal to metal and do not require lubrication. 
    • Do not force connections for any reason. They should be easily assembled by hand. 

Step 8: Tighten the hose connections with a wrench

• • • Note: Again, only use a non-adjustable wrench meant for welding. This will keep your gases from leaking.

Test for Leaks 

Step 9: Close both torch valves, then individually open and test.

• • For oxygen, turn the regulating screw until the gauge reads 25 psi.
  • For acetylene, turn the regulating screw until the gauge reads 10 psi. Listen and smell.

Step 10: Apply a leak-test solution with a brush

• • Apply solution to the cylinder valves, the cylinder and regulator connections, and all the hose connections. You can buy a solution designed for this specific purpose. Use a clean brush that has not been contaminated by oil or gas.

Step 11: Check for bubbles

• • Small bubbles indicate that there is a leak in your connection, and it either needs to be tightened or reattached. Let the solution sit for 1-2 minutes before checking for bubbles. If there is a leak, release all pressure from the system.
  • Reattach or tighten as needed and re-check for bubbles.
  • After testing, turn off the oxygen and the acetylene.

Setting Operating Pressure

Step 12: Turn the Oxygen regulator adjusting screw

• • Begin with the adjusting screw fully out and loose.
  • Open the Oxygen valve on your torch.
  • Turn the adjusting screw until you reach your desired pressure.
  • Close the torch oxygen valve.

Step 13: Turn the Acetylene regulator adjusting screw

• • Open the acetylene valve on your torch and open the adjusting screw.
  • Close the torch valve when you reach your desired pressure.

*WARNINGS:

• • • Do not exceed 15psi or your cylinder may combust. 
    • Do not open the cylinder valve more than one full turn. 

Lighting Your Torch 

Step 14: Open the torch Acetylene valve ½ turn and strike a flame

• • Use a friction striker, not matches or cigarette lighters for this step. There should now be a flame coming out of your torch.
  • *If not, turn off the acetylene valve and check your connections.

*WARNING: Do not have the Oxygen gas flowing when you light your torch.

Step 15: Reduce the Acetylene flow by adjusting the torch acetylene valve

• • Reduce the Acetylene flow until you see black smoke appear.
  • Open it up until there is no more black smoke.
  • There should be a short, 1 inch thin line of flame extending from your torch tip before it widens out.
    • Note: Put on shade 5 goggles

Step 16: Slowly open your torch oxygen valve

• • Reduce your oxygen until the white flame created by the oxygen disappears.
    • You should see a blue flame, with a triangular cone coming out of your torch tip. This is a neutral flame.
      • Note: If your flame suddenly goes out, this is a backfire, which can happen when your torch touches metal. Make sure your tip is still clean and relight your torch.

*WARNING: If you hear a loud hissing or squealing, turn off the torch and re-check your set up. This may be indicative of a flashback.

You are now ready to weld!