gas welding

GAS WELDINGAndrew Brock

Terms

The burning qualities of gases are used in Ag Mechanics to heat, weld and cut metals

Weld- to join by fusion Fusion- melting together Oxyacetylene- a shortened version of

the two words oxygen and acetylene in reference to equipment and processes where the two gases are used together.

Terms

Torch- an assembly that mixes gases and discharges them to support a controllable flame

Cylinder- is a long round tank with extremely thick walls built to hold gases under great pressure

Valves and regulators- devices that control or regulate the flow of gas

Terms

Oxyfuel- refers to the combination of pure oxygen and a combustible fuel gas

The gas flame from an oxyfuel gas will burn at about 5000-6000* F

Kerf- the opening left in the metal after cut Brazing- the process of bonding with metals

and alloys that melt at or above 840*F Brass- a mix of copper and zinc used in

brazing Fusion Welding- joining metal by melting

Setting Up

Acetylene Equipment is color coded red

The valve on most acetylene cylinders is protected with a high collar

All Acetylene couplings have left hand threads and notched fittings

Setting Up

Oxygen cylinder valves are generally not protected during use, however heavy caps protect them when not is use

Oxygen equipment is color coded green

All Oxygen couplings have right hand threads

Firing Up the Torch

1. Close the Acetylene Valve on the torch

2. Close the Oxygen valve on the torch3. Open the oxygen valve slowly until

the pressure gauge responds then open it all the way

4. Open the acetylene valve slowly half a turn

5. Make sure the oxygen gauge reads 10 psi

6. Make sure the acetylene gauge reads 5 psi

Firing up the torch

7. Be sure that you have on leather gloves and number 5 shaded glasses

8. Open the acetylene valve one eighth turn

9. Use striker to ignite the torch10. Open the acetylene valve slowly until it

stops smoking11. Open the oxygen valve slowly until the

inner blue flame becomes several small flames when the lever is held

Cutting

Hold the flame on the edge of the metal until the metal becomes red in color

Then press the lever down and slowly cut across the metal

If it stops cutting release the lever and start again

Safety

Make sure your feet are protected, never use a torch while wearing flip flops or open toed shoes of any kind

Make sure your pants are not fringed, you don’t want to be on fire

Let the metal cool before picking it up.

Safety

Tanks should be chained in a cart to prevent them from falling. Tanks not in use should be stored separately with caps on as well as chained to wall.

Equipment can be checked for leaks using soapy water.

NEVER USE OIL AS A LUBRICANT ON OXYACETYLENE EQUIPMENT!

Graphite can be used to lubricate parts.

Turning off the torch

1. Turn off the acetylene cylinder2. Turn off the oxygen cylinder3. Open the oxygen and acetylene

torch valves and bleed the lines until the regulators are on zero

4. Shut all the valves off5. Roll up the torch lines around the

cart

Oxygen Torch valve

Allows oxygen into torch handle mixing chamber.

The more you open the more gas that flows.

Acetylene Torch valve

Allows acetylene into torch handle mixing chamber.

The more you open the more gas that flows.

Torch Body

Made up of the torch valves and mixing chamber.

Welding tips attach to body.

Two types of tips attach to torch body. Welding Cutting

Welding tip

Used to weld or braze metal.

Small sizes for thin metal and larger sizes for thick metal.

Tips sizes range from 1 to 9.

Cutting tip

Used to cut metal. Has an oxygen

control valve and an oxygen cutting lever.

Oxygen torch valve must be open all the way to use the cutting torch.

Acetylene fusible plugs

Found on top and/or bottom of tank.

Acts as a relief valve if pressure gets to high so tank won’t explode.

Welding rod

Used as filler rod when welding.

Diameters range from 1/16" to 1/8". Small rod for thin metal.

About 42,000 lbs. tensile strength.

Brazing rod

Used when welding is to hot or when strength isn’t as critical.

We have 2 rod sizes, 3/32" and 1/8".

We have flux covered rods and bare rods.

Do not melt base metal when brazing.

Other Equipment

Friction lighter Used to light

oxyacetylene torch.

Tip Cleaners Used to clean dirty tips.