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Technology Education Dept. Bellwood-Antis High School Mr. Crowell Mr. Mackereth.

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Presentation on theme: "Technology Education Dept. Bellwood-Antis High School Mr. Crowell Mr. Mackereth."— Presentation transcript:

1 Technology Education Dept. Bellwood-Antis High School Mr. Crowell Mr. Mackereth

2  WELDING - the heating of pieces of base metal to melt & fuse 2 pieces into a solid piece (also called FUSION WELDING.)  Welding involves using a SIMILAR filler metal/rod to the pieces being welded.  Example of WELDING: two steel pieces fused together with a steel rod is welding

3  BRAZING is also the heating of pieces of base metal to melt & fuse the two pieces into one solid piece.  Unlike welding, BRAZING uses a NON- FERROUS filler metal with a lower melting point to the pieces being welded.  Example of BRAZING: 2 steel pieces fused with a brass or bronze rod is BRAZING

4  All types of gas welding use OXYGEN to OXIDIZE (burn) a type of flammable gas.  Although different welding fuels are used, the most common fuel, and the gas we will be using in this shop, is ACETYLENE.  Welding with OXYGEN and ACETYLENE is called OXY-ACETYLENE WELDING.

5  Proper welding attire/equipment in our shop would include the following items:  HAT w/ HAIR TIED UP  LONG SLEEVES  SOLID SHOES/BOOTS  LONG PANTS  #5 WELDING GOGGLES  LEATHER WELDING COAT  WEDLING GLOVES  LEATHER WELDING APRON  Basically, keep ALL of your skin and hair covered when welding!

6  The tanks, especially oxygen, are filled with highly compressed gases.  IT IS EXTREMELY CRITICAL THAT ALL TANKS BE SECURELY CHAINED AT ALL TIMES!  A tank with a cracked or broken valve becomes a deadly projectile or missile.

7  Check to make sure the regulators on the tank & the pressure regulators on the torch body ARE BOTH IN THE CLOSED POSITION.  We then open the oxygen tank valve ALL THE WAY OPEN This prevents the valve stem on the tank valve from being bent by high pressure.  We then open the ACETYLENE tank valve ONE QUARTER TURN. NO FURTHER!  LEAVE THE TANK WRENCH ON THE ACETYLENE TANK VALVE.  This allows us to shut the gas off quickly in the event of an emergency, such as a leak or fire.

8  We make sure that the gas and oxygen lines cannot be switched accidentally:  OXYGEN hoses are GREEN, ACETYLENE are RED   OXYGEN fittings have RIGHT hand threads. ACETYLENE fittings having LEFT hand threads.  The ACETYLENE packing nut has a groove notched into IT. The OXYGEN packing nut has no groove.  ALL Fittings must be tight. NO grease or petroleum products can be in threads!  The torch body is equipped with either a welding tip or a cutting tip. Make sure to keep all tips clean.

9  The projects you are building will be made out of 3/32” steel welding rod.  This steel rod is plated with a thin layer of copper to prevent rust from forming on the outside of the rod, or contaminating welds.  The steel project pieces will be BRAZED together. The brazing rods used are 3/32” brazing rod with a coating of flux on the rod.

10  IMPORTANT: NEVER POINT A TORCH AT ANYONE OR ANY FLAMMABLE OBJECT WHEN LIGHTING THE TORCH.  FIRST, set the regulators on the tanks to the desired amounts of pressure. (For our brazing, we will be using 5 lbs of oxygen and acetylene.)  Once the correct pressures are set, open the ACETYLENE pressure valve on the torch body 1/4 turn, and then strike the spark lighter.  LIGHT THE GAS WITH A SPARK LIGHTER!  NEVER USE MATCHES / BUTANE LIGHTERS!

11 SSlowly add OXYGEN to the acetylene flame until a pale blue flame with an inner blue core appears. This is called a NEUTRAL FLAME. IIf too much acetylene is burned, a CARBURIZING FLAME will leave black deposits on the work. Slowly add oxygen to neutralize the flame. IIf too much oxygen is added to the acetylene, then an OXIDIZING FLAME will eat away at the filler rod and the base metal. Cut back on the oxygen. VVERY IMPORTANT! DDO NOT POINT A LIT TORCH AT ANYONE, DDO NOT LAY DOWN A LIT TORCH ON A TABLE!

12  FIRST, shut both pressure valves on the torch (acetylene first, then oxygen)  SECOND, close the tank valves tightly (acetylene first, then oxygen)  THIRD, drain both of the lines by opening the torch pressure valves. Do this until both pressure gauges on the tanks read ZERO.  FINNALY, Shut the torch valves, and shut the regulators on the tank. TURN the screws out. (only done at the END of CLASS by instructor)

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