1. Oxy – Acetylene Welding
Basic FUNDEMENTALS
Torch Start Up & Shut Down
Safety

2. CYLINDERS:

3. CYLINDERS- Bottles containing gas that we use for welding.
Bottles can be privately owned or leased from a supplier. Demurrage is payment for leasing.
They are controlled by the Interstate Commerce Commission who track registration, shipping, testing etc.
The name of the owner is usually stamped into the top ring of the bottle.
If you buy one from someone other than a dealer, keep the receipt.
If you own your cylinders, you are responsible for paying for testing. Also, many times it is hard to get your own cylinder back. When you go to fill a cylinder, you will drop yours off and exchange it for a full cylinder. Then your cylinder is put out into circulation. In order to get your own cylinder back it often takes weeks. Some small companies will not exchange personal tanks and you will have to drop it off to be filled and then pick it up later.
The ICC number on the tank will track it’s history. If you buy your own at a yard sale or from a friend keep the reciept. If the tank shows up as stolen on the companies computer you must show proof that you paid for the tank from someone else. If you can not prove this you are liable for up to a 5,000 dollar fine.

4. OXYGEN CYLINDER:
¼” minimum thickness of armor plated steel. A single piece.
Hydro tested every five years for pressure.(Ten years if it has a star after the date)
Right hand threads. Righty tighty, lefty loosey.
2200 lbs p.s.I when filled. Very high pressure.
Double seated valve to prevent gas leakage.
Safety disc in the back of the regulator and valve.
Never oil or grease any part to the oxygen system.
One single sheet means that a large ram is pushed into the hot metal, forming the tank around it like a sleeve. No welds because the tank is high pressure and there could be an explosion.
The tanks are tested orthoscopically by a small camera on the inside that looks for any cracks or types of rust. They are then submerged into a tank of water and pressurized to look for any air escaping.
By having a separate thread type than acetylene Tanks you can not interchange regulators from the high pressure oxygen to low pressure acet.
Double seated valve means that the tank must be all the way open or all the way closed. If the valve is halfway open gas will chase the threads in the valve and leak out.
The safety disc in the back of the regulator controls pressure. If the tank over pressurizes the cap will blow out and let off excess pressure.
Petroleum products and pure oxygen will spontaneously combust when near each other. Do not let oxygen soak into your clothes or try to oil a regulator if it squeaks. The soft brass material in the regulator is supposed to squeak it is not a problem.

5. Acetylene Cylinder: 250 p.s.I when full. Low pressure.
Acetylene is absorbed in an acetone and porous material mixture. Never exceed 15 p.s.I.
Fuse plug in the bottom melt at 250°.
Left hand threads. No righty tighty, lefty loosey.
Open the acetylene valve ¼ to ½ turn at most.
Always keep the bottle upright, not on it’s side
Purple flame means acetone is burning.
Always keep cylinders capped when not in use and chained to prevent them from falling over.
“THINK SAFETY”
About ten times less pressure than an oxygen cylinder.
The tank is filled with diatamatious earth to form a cushion for acetylene gas. Acetone (also a fingernail polish remover) is added to stabilize the gas inside the tank. On it’s own, acetylene gas will ignite in the air 80% of the time, it is very volitile. Acetone helps to keep the gas at a stable rate.
Fuse plug in the bottom is a lead alloy that will melt out in case of a fire. This still means that there will be a fire but hopefully no explosion. There are also three welds on an acetylene tank so that the pieces will blow apart in big chunks and not in tiny shrapnel pieces.
Left hand threads so that you can not put on an oxygen regulator.
We only open the valve ¼ to ½ turn so that if the flame travels back through the hoses to the tank, it will not take a long time to turn the tank off.
When the bottle is on it’s side the acetone will rise to the top and burn instead of acetylene and the flame will turn purple. This also happens when the tank is empty.

6. FIVE STEPS TO LIGHT THE TORCH:
LIGHT MY FIRE!!!

7. I. Visual check of equipment
Check the regulators for any damage.
Check hoses for cuts, burns, or loose fittings.
Check the torch. Valves must be turned off, proper tip and the tip is in good repair.
It is escential that all parts of the torch assembly are checked to make sure there is no damage. This doesn’t mean that you will need a magnifying glass to look everything over, but connections do become loose and sometimes valves are left on. Be sure to make yourself safe!

8. II. Check the regulators.
Check that the adjusting valves are out-off-free. (Or that there is no pressure on them)
Gauges should read “0”-if not, bleed the lines and relieve the valves to start from scratch.
Make sure that there is no pressure on the gauges. Even if the numbers look right, if someone left it on, you can never be sure. If you show pressure take the time to bleed it out and start from scratch that is the only way to be sure it is done right.

9. III. Turn on the sources-slowly.
Open the acetylene source or cylinder Cylinder ¼ to ½ turn
Wall is all the way and ½ turn back
Open the oxygen source or cylinder
Stand to one side of the unit
Cylinder is opened all the way
Don’t confuse the tank with the wall source. We need to have the valves turned halfway back so that they do not stick. If stuck open, a wrench must be used to close them again.

10. IV. Dial in the regulators
Oxygen for welding, set at 7. For cutting set at 30.
Acetylene is set at 7 for both functions.
Setting the pressure at 7 does not mean that you turn the adjusting screw seven times. Slowly turn the screw to the right and watch the gauge. The pressure doesn’t have to be perfect but it should be close. If you go too far, simply turn off the source, bleed the line and loosen the screw. Then start from scratch.
NEVER EXCEED 15 PSI ON THE ACETYLENE

11. V. Light the torch and adjust the flame-Goggles on!
Open the acetylene torch valve slightly.
Light the torch with a striker. Point the torch inside the booth toward the bricks. Watch out for the hoses! Add acetylene until the flame is barely flared at the end.
Open the oxygen valve slowly and adjust to a neutral flame.
While adjusting the flame your goggles should already be on. This will limit the chance of damage to your eyes. Be sure to point the torch towards the bricks, down and away so you do not burn the torch hoses. If you hear a whistling noise while adding oxygen, turn off the torch and clean the tip out.

12. STEPS CONT.
Up to this point, the flame produced is the best for this tip size. If need you can increase or decrease the flame size for more weld control.
For a larger flame (hotter), increase acetylene then oxygen to neutral.
For a smaller flame (cooler), decrease the oxygen then the acetylene to a neutral flame.
Remember, once at a nuetral flame, to provide a hotter flame you must add acetylene and then oxygen. For a colder flame Reduce the oxygen then the acetylene. Just adding one or the other gas will only provide an unstable flame.

13. TO REVIEW, THESE ARE THE STEPS TO REMEMBER FOR THE TEST.
VISUAL CHECK OF EQUIPMENT.
CHECK THE REGULATORS.
TURN ON SOURCES.
DIAL IN THE REGULATORS.
LIGHT THE TORCH AND ADJUST THE FLAME.
Show DVD chapters 1 – 3 on Equipment, Regulator adjustment and Torch adjustment. Go over pages 127 – 138 in Modern Welding with the students reminding them that they will be doing the chapter questions on this chapter. The answers to questions 1-14 can be found in these pages. Answer these questions.

14. FIVE STEPS TO SHUT DOWN
BAD FLAME, GO HOME

15. I. At the torch handle Turn off the oxygen torch body valve.
Turn off the acetylene torch body valve.
If shutting down for the day, continue…
We turn off the oxygen first for several reasons. The most important of which is that once the acetylene is turned off there is no longer a flame, in our loud shop it is not always possible to still hear the oxygen coming out of the torch. There are many times that the flame is turned off and oxygen is still being released which is a huge loss of fuel.

17. II. Turn off the sources.
Cylinders or wall valves go all the way off-no half way.

18. III. Bleed both systems.
Open the acetylene torch valve and watch the gauges go to “0”. Close the torch valve.
Open the oxygen torch valve and watch the gauges go to “0”. Close the torch valve.
This step is very important and is often forgotten or misplaced. Many students will try to loosen the adjusting screw now to get rid of the gas pressure but this does not work. You must open both valves and watch the gauges drop to 0 before you touch the adjusting screw. If you did the steps out of order you must go back to the original set up and start over.

19. IV. Relieve the regulators.
Turn the adjusting screws out-off-free.
To do this you so not have to screw them out until they fall out of the regulator. Just until it is loose.
Too many times the adjusting screw is turned out to the point that it falls out of the regulator. To loosen the screw, simply turn it to the left until it feels slightly loose in the threads no more. Usually two turns will do this.

20. V. Clean Up.
Mark or cool hot metal and then store it in the proper bin.
Inspect and put away all equipment.
Put your stool up, pliers back, goggles away and then clean your designated area.
Only mark hot metal that cannot be fit into the quenching tanks to cool. All other metal must be cooled down and stored in the appropriate container. Do not leave metal in the quenching bucket!!!!!!

21. TO REVIEW, THESE ARE THE STEPS TO REMEMBER FOR THE TEST.
Turn the torch handle off.
Turn off the sources.
Bleed both systems.
Relieve the regulators.
Clean up.
Show DVD chapter on Equipment shutdown.

22. CARBONIZING FLAME NEUTRAL FLAME OXIDIZING FLAME
THE THREE FLAMES:
CARBONIZING FLAME
NEUTRAL FLAME
OXIDIZING FLAME

23. Notice how the cone and feather are stretched out and not together
Notice how the cone and feather are stretched out and not together. This is the easiest way to tell that your flame is not adjusted correctly.

27. WHICH WAY DO I GO? Forehand welding: Backhand welding:
Angle the torch into the weld and push the puddle.
This is the easiest to learn and works best on thin metal.
Backhand welding:
Angle the torch away from the weld and drag the puddle.
This is harder to control but works well on thicker metal.
70 deg
Figure A
1/8”
70 deg
Figure B

28. Torch Motion
Puddles – running a molten puddle of base metal across the plate. The puddle should penetrate the metal. The torch should move in ovals and the cone should be 1/8” above the base metal. Never touch the tip to the base metal. Be patient!

29. Bead – Running a puddle and adding the filler rod to the center of the puddle. Use a dabbing motion with the filler rod, do not melt the rod with the torch. Hold the filler rod close to the cone to keep it warm. Maintain the oval torch motion.

30. Tack – A small weld holding 2 pieces together for positioning and securing to recheck layout and weld. Align the pieces and gap slightly. Heat both pieces, add filler, and fuse them together. Tack every 1 to 1 ½” for thin metals. The number of tacks you use will depend on the metal thickness.

31. Filler Rods C.C.M.S. – Copper Coated Mild Steel
Usually 36” in length and 1/16”, 3/32” and 1/8” are most common
Code – Ex. GA50 or GB45
G = Gas A = high ductility
B = Low ductility
Last 2 digits are tensile strength X 1000 psi.
Show DVD on Weld Beads 1,2,and 3, then Weld Joints. Go over pages in Modern Welding. Questions can be answered from these pages.

32. Oxy-acetylene Welding Problems.
Torch will pop, whistle, go out or all three. This means that you have experienced a backfire or a flashback.
Tip is dirty
Tip is too small
Tip is too big
“O” rings are bad
Cone is too close to the metal
Tip is loose

33. Flashback or Back fire?
With a backfire, black smoke will come out of the tip and the handle will get hot. Follow steps closely. A flashback is the burning of the gases in the tip only.
For a backfire:
Turn off the torch valves
Turn off the sources
Notify the instructor
Check over equipment together

34. Other problems:
Too cold – the bead will sit on top of the metal like a ball, not fused on the sides.
Too hot – the bead sags through the metal. May burn holes.
Oxidizing flame – dirty and bubbling with lots of sparks.
Carbonizing flame – Metal turns black and cannot control the puddle.
Filler rod sticks – don’t panic. Slowly move the torch over to melt it off. Dab in center of puddle.
Show DVD chapter Weld Beads section on torch popping.

35. Eye protection Goggles- protect your eyes from glare and sparks.
Filter plate = #4 to #5 shade lens
Assemble goggles in correct order.

36. Never:
Exceed 15 PPSI on the acetylene cylenders.
Use oil or grease on any welding aparatus.
Light the torch with a match or lighter
Light the torch with both valves open.
Open acetylene tank more than ½” turn.
Relight torch from hot metal or another torch.
Watch or work without goggles.
Wear nylon clothing when using the torch
Weld on anything that has gas, oil or solvent in it.

37. Ask questions if you are not sure. Use correct equipment for the job.
Always:
Ask questions if you are not sure.
Use correct equipment for the job.
Use eye protection #4 or #5 shade lens.
Use a striker to light the torch.
Use soap and water to check for leaks.
Crack (turn on then off) cylenders before attaching regulators.
Un-dial/release adjusting screws on regulators.
Use a tip cleaner of proper size.
Keep area clean.
Show DVD on Weld Beads section on good welds. All 25 chapter questions should be done. Review and test, hand in questions and notes with the test.