1. Oxygen Acetylene Welding

2. OXY-ACET EQUIPMENT
Go over the parts of the outfit. Explain the difference between tanks and manifold.

3. I. CYLINDERS
Cylinders are controlled by the Interstate Commerce Commission.
If you buy one from a second party, get a receipt. Stolen tanks can result in jail time and fines.
ICC # is located on the top ring.
Make sure that you receive a receipt for a tank that you purchase from anyone but a dealer. If that tank had been stolen and you can not prove that you received it from another person, you are responsible and could go to jail.

4. A. OXYGEN Cylinder – Usually Green
Right hand threads.
High pressure p.p.s.i
Never oil or grease any part of the oxygen system.
Always turn valves on all the way to prevent gas leakage.
Oxygen cylinders are made of one single sheet of armor plated steel. There are no welds on the tank, the sheet is super heated and then a hydraulic ram pushes in and forms the shape of the tank. They are made from one piece of steel because the tanks are very highly pressurized. Any weld or seam that might crack or fail could cause the entire tank to rupture.
Threads are right hand which means they tighten to the right and loosen to the left.
We always turn the cylinder on all the way. If the tank is turned on half way or only slightly, the gas can leak out of the threads in the valve and we waste a tank of gas.
Never use a petroleum product on any part of the oxygen system. Oxygen and oil products will spontaneously combust.

5. B. ACETYLENE Cylinder – Usually yellow or red
Low pressure.
Tanks filled with a silicon mold to cushion the volatile gas.
Never exceed 15 p.p.s.i
Left hand threads.
Open Acet. Valve ¼ to 1 full turn at most.
Fusible plug at the bottom that will melt out if there is a fire. Lead alloy plug.
Acetylene cylinders are made from three separate pieces of steel that are welded together. They are made in pieces so that if there is an explosion the tank will separate into three large portions and not tiny bits of shrapnel. There is also a fusible plug in the bottom of the tank that melts away at about 250 degrees. If there is a fire around the tanks the plug will melt and the gas will leak out. This means that there will still be a large fire but no explosion.
Acetylene gas is extremely dangerous to handle. It can ignite and explode on its own if not handled properly. The tanks are filled with a porous mixture that helps to keep the gas stable. Originally this was diatimatious earth or kitty litter. The tanks were filled with this and then the gas was inserted. Now, most tanks use a silicon mold that works in the same fashion. In addition to this cushion, the chemical acetone is added to the tank. Acetone is heavier than acetylene so it sinks to the bottom and forces the acetylene to rise out the top. The acetone also works as a monitor on the tank. Acetone burns with a purple flame so if your torch starts to burn with a purple hue, you know that you are running out of acetylene and are burning the acetone.
We never exceed 15 pounds of pressure on the tank so that it will not explode. Anything over 15 pounds and we run the risk of explosion when the gas is let out of the torch.
Acetylene tanks have left hand threads which is the opposite of oxygen. This is the same with most fuel gases. In this way you can not exchange the regulators of the oxygen and acetylene units.
We only turn on the tanks ¼ to 1 full turn for safety purposes. In the same way that fire can travel back up the stream of lighter fluid and blow up the can, fire can work it’s way into the torch if the circumstances are right and burn back though the lines to the tank. If this ever occurs, we want to be able to turn off the tank as fast as possible and not stand there for minutes turning the handles.

6. Ruler quiz. Fill in the fraction. 16th scale.8 4 12 6 14 2 10 1 3 5 7 9 13 11 15
Either draw a ruler and label the lines or number your paper from 1-15 and write in the correct answers.

7. II. FIVE STEPS TO LIGHTING THE OXY-ACET TORCH
These are the steps that we follow every time that we light the torch. It is extremely important that you don’t skip over any of these steps for safety reasons.
These are also the steps that you will have to write in on your safety exam. So it would be a good idea to underline or highlight the lettered headings of each so that you can study them later.

8. A. Visual check of equipment.
Check hoses for cuts, burns or loose fittings.
Check torch – Valves turned off, proper tip & tip in good repair.
Start at the tip of the torch and work your way back. Check that the tip is secured tightly, next that the torch valves are turned off to the right. Next check the hose connections are tight at the torch. Then we need to check the hoses. There will probably be some dark marks or dirty rubber and that is ok, however you need to look for cuts or holes in the line. This could result in a fire at your feet instead of out of the torch tip.

9. B. Check regulators Adjusting valves must be out/off/free
Gages should read “0” – if not bleed lines and relieve valves.
Look at the gauges and see if they read zero. Next twist the adjusting screw on the regulator to be sure that it is loose. If the screw is tight, when you open the source the pressure can jump up quickly and possibly rupture the regulator.

10. C. Turn on sources – SLOWLY
Open acetylene valve ¼ to 1 full turn at most.
Open oxygen valve slowly.
Stand to one side of unit.
Open valve all the way SLOWLY
When opening the sources it does not matter which one goes first. Open both valves all the way to the left but only until the valve stops do not over twist. Be sure you are opening the silver valves.

11. D. Dial in regulators (Adjusting screws)
Oxygen
For welding set at 3-7 p.p.s.i
For cutting set at p.p.s.i
Acetylene
Set at 3-7 p.p.s.i for both functions.
Again, it doesn’t matter which regulator you start with, take the gold “t” handled screw in the center of the regulator and turn it slowly to the right. Watch the gauges while you turn, we want the needle to stop at about 7 pounds. This does not have to be exact, you can be off by a pound or so.

12. Properly adjusted regulators.
Here is how the regulators should look if you have adjusted them properly. You can see that the first number printed on the oxygen regulator is 20, at the second red triangle. We will assume that the first red triangle is 10 so we will stop the needle just before it.

13. E. Light the torch (goggles on) Adjust the flame.
Open the acetylene torch valve ¼ turn.
Light the torch with a striker – point torch under vent and adjust to no smoke. (Do not gap flame)
Open Oxygen valve slowly and adjust to desired flame.
We light the torch with acetylene gas first. The flame will be orange and will produce quite a bit of smoke. Make sure that the torch is pointed inside the booth under the vents. The flame should be small at first, add acetylene until the flame becomes long and feathered out at the end and most of the smoke disappears. Next we add oxygen until the blue cone reaches all the way down to the tip.

14. III. FIVE STEPS TO TURNING THE OXY-ACET TORCH OFF
These steps will also be on the safety test as well so make sure to highlight them in some way.

15. A. Torch handle Turn off the oxygen torch body valve.
Turn off the acetylene torch body valve.
We turn off the oxygen first for two reasons. First, the manufacturer of this brand of torch recommends this as the safest method. Second, when you turn off the acetylene, the flame goes out and many times students think that if the flame is gone they are done. They hang up the torch and walk away, all the while oxygen is leaking out.
Next turn off the acetylene valve. If any bit of flame remains once both valves are turned off to the right, blow it out like a candle.

16. B. Turn off sources – cylinders
Turn both silver valves all the way to the right. It does not matter which one is first.

17. C. Bleed both systems
Open acet. torch valve – gages should go to “0”, close torch valve
Open oxygen torch valve – gages should go to “0”, close torch valve.
We now have turned off the gas to the hoses and torch and trapped some gas in the hoses. To release this pressure, open the acetylene torch valve first and watch the regulators, they should drop to zero, then close the torch valve.
Do the same thing with the oxygen torch valve checking that the gauge drops to zero.

18. D. Relieve the regulators.
Turn adjusting screws out/off/free
We relieve the regulators by loosening the adjustment screws to the left. We only want to loosen the screws so two or three turns should do the trick. This screw is like any other bolt or screw, if you turn it too far it will fall out of the regulator and we will have problems threading it back in.

19. E. Clean up. Mark or cool hot metal. Inspect and put equipment away.
Put stool up, pliers back, goggles away, then clean work area & floor.
It is important to always cool any metal that you have worked with and not leave it for someone else to do. If for some reason the metal is to large to fit in the quenching tanks mark it with soap chalk as many times as possible. Check to make sure your equipment is still in good shape.

20. IV. THE THREE OXY-ACET FLAMES
After the torch is lit, you must adjust the oxygen and acetylene to the proper flame for the job.
The next slides deal with different types of flames that you can use while welding. We will be using the neutral flame only. Every welder and every weld will require different settings when you gain experience you will be able to make more subtle adjustments.

21. A. CARBONIZING FLAME – Too much acetylene, not enough oxygen
A. CARBONIZING FLAME – Too much acetylene, not enough oxygen. Also called a reducing flame °
You will see black soot on the metal at times or the metal may just not melt at all. We can use this flame to anneal metals like aluminum to make it softer and easier to work with.

22. B. NEUTRAL FLAME – Equal amounts of oxygen and acetylene. 6000°
This is the flame we will be using the most.

23. C. OXIDIZING FLAME – More oxygen than acetylene
C. OXIDIZING FLAME – More oxygen than acetylene ° The metal will bubble and boil.
This flame is the easiest to see since the metal will boil and bubble and be very hard to control. You may also hear a slight hissing sound that may lead you to think that the torch needs to be cleaned.

24. Ruler quiz. Fill in the fraction. 16th scale.8 4 12 6 14 2 10 1 3 5 7 9 13 11 15
Either draw a ruler and label the lines or number your paper from 1-15 and write in the correct answers.

25. DEFINITION OF TERMS Welding – Joining of 2 like metals with or without 3rd like metal through fusion. (Cohesion)
We can not weld different types of metal together, metals like copper, aluminum or cast iron can not be welded to steel or to eachother except through a process called explosion welding. True welding can only be done with the same types of materials, steel to steel etc.
This can be done with the addition of a filler rod of the same type of material which will make the weld stronger.

26. Definitions Cont. Brazing and Soldering:
These methods are used when joining two different materials that can’t melt together.
Brazing happens over 800° Soldering is under 800°

27. WELDING PROCEDURES
Once you obtain the proper flame, hold the torch so the tip is perpendicular to the work on both planes.
Forehand – Angle the torch into weld & push the puddle.
Easiest to learn
Thin metals
Preheats metal
Forehand welding for right handed people is moving right to left, for left handers it is the opposite, left to right. You want to angle the torch in the direction of the weld by at least 20 degrees, more depending on metal thickness.

28. Torch motion
In oxy welding a circular or side to side motion is recommended for the best looking weld. You can make a weld that is just as strong simply by holding the torch still as long as the metal melts all the way. The welds will not look as nice if you don’t use motion however.

29. Puddles – Running a liquid puddle of base metal across the plate
Puddles – Running a liquid puddle of base metal across the plate. The puddle should penetrate the metal. Cone should be 1/8” above base plate.
A puddle is simply melting the metal with the torch and moving that melted metal across the plate. Make sure that them torch tip never actually touches the plate and try to make even circles with the torch. If the puddle gets too big, you either need to move faster or turn the gasses down on the torch for a cooler flame.

30. Bead – Running a puddle and adding a filler rod to the center of the puddle. Use a dabbing motion with the filler rod. Hold it in the flame – keep the end of the rod red hot.
A bead is made by adding filler rod to the liquid puddle. The filler rod melts into the liquid metal and adds to it. You need to be sure to melt the filler material in the puddle of metal and not with the torch itself. If the filler material sticks to the metal don’t panic, simply move the torch over the stuck filler material until it melts off then continue on with the puddle.

31. Tack – A small weld holding 2 pieces together for positioning and securing to recheck layout and weld. Align pieces – gap (space depends on metal thickness). Heat both pieces, add filler and fuse both plates together.
Tacking metal before you weld it ensures that the metal will stay in place. Metal warps as heat is applied and will move from its original location making it impossible to weld or may change the look of the final weldament.

32. Filler Rod – Classified by the A.W.S. (American Welding Society)
36” lengths – 1/16”, 3/32”, 1/8” dia. Most common
Usually these are three feet long but that can cause many problems in the welding process. First any movement on the back end of the rod will move it tremendously at the welding end causing the rod to stick. Also with so much of the filler rod sticking out behind the welder it is easy to poke someone in the face or eye.

33. OXY-ACET WELDING PROBLEMS
There are a great many problems that can occur with the oxy welding process, however most of them can be avoided if safety precautions are taken and torch set up is right. These problems will be on your test so make sure to mark them.

34. Torch will pop – whistle – go out – or all three, which, means you have experienced a Flashback or Backfire. Causes are:
Tip is dirty
“O” rings are bad
Tip too small (flame too large)
Cone too close to metal
Tip is loose
Tip too big (flame too small)
You need to know the difference between a backfire and a flashback. A backfire is the same as in a car. There is a burning of the gases in the torch which causes a loud pop, at times causing the torch to blow out or whistle. This is not a major concern although the more it happens the more likely we are to have defective equipment.
These are the likely causes for a backfire and are things to look for. You will need to know at least four out of the six for your test.

35. Flashback / Backfire – With a Flashback, black smoke will come out of the tip and the handle will get hot. A backfire is a burning of the gasses in the TIP only. If you have a Flashback, do the following in this sequence:
Turn off torch valves
Turn off sources
Notify Instructor
Check equipment
A flashback is when the flames move back into the torch and through the lines and into the tanks causing an explosion. When you have a flashback, it will sound exactly like a backfire, the only difference is that black smoke will come out of the tip of the torch, indicating that the fire is burning in the torch.
If you have a flashback or are concerned, follow these steps in this exact order. This is extremely important.
You will need to define a flashback and write in these four steps in order on your test otherwise you fail.

36. Too cold – (flame too small) – Bead will sit on top of plate, shallow penetration, not fused together.
Many students will have welds where the filler rod does not melt into the steel. You want to look at your welds and make sure that it melts in on either side. If it does not, take the torch and run a puddle over the original adding no more filler rod. Allow the metal to fill in going slow enough to melt it.

37. Too hot – (flame too big) – Bead sags, too much penetration
Too hot – (flame too big) – Bead sags, too much penetration. Hole burned in metal.
This sagging of the metal shows a weakness in the material.

38. OXY-ACET WELDING SAFETY

39. Goggles Protect you from glare and splatter.
Filter plate - #5 shade lens
Never watch or work without wearing a set of protective goggles. You should be able to see through the goggles well. If you can not see anything, the filter lens is not the appropriate shade.

40. NEVER… Exceed 15ppsi on acetylene line pressure regulator.
Use oil or grease on any welding apparatus.
Light the torch with both valves open.
Light the torch with a match or lighter.
Open acetylene tank valve more than 1 full turn.
Relight torch from hot metal or another torch.
Watch or work without goggles.
Wear nylon clothing when using torch.
Weld on anything that has had gas, oil or solvent in it.