2.1 Indicate the alloy metal that is specifically used to manufacture the following products and give TWO reasons why the metal is used: 2.1.1 Milk tanks 2.1.2 Fittings for hot-water copper pipes 2.1.3 Hammering tools that can be used in explosive atmospheres 2.2 Name TWO hot-working processes that can be used to change the structural properties of brass - NSC Agricultural Technology - Question 2 - 2018 - Paper 1

The alloy chosen for fittings in hot-water copper pipes is brass. The reasons for this selection include:

1. Strength: Brass provides significant strength, reducing the risk of breakage under heat and pressure.
2. Corrosion Resistance: It has excellent corrosion resistance, ensuring the fittings last longer in demanding environments.

For hammering tools utilized in explosive atmospheres, bronze (Beryllium Copper) is the alloy of choice. The reasons are:

1. Spark-Free Operation: Bronze does not generate sparks, crucial for safety in explosive environments.
2. Low Friction: It has low friction properties, which help in preventing overheating and wear during operation.

1. Annealing: This process involves heating brass to a specific temperature followed by controlled cooling, which softens the metal and improves ductility. 2. Stress Relieving: This technique is used to reduce internal stresses within the brass, enhancing its structural integrity.

1. Lightweight: Fibreglass troughs are easy to move and reposition compared to heavy concrete troughs. 2. Rust Resistance: These troughs do not rust, whereas concrete may deteriorate over time due to weathering and water exposure.

The resin used in manufacturing fibreglass products is a low viscosity fluid that can be transformed into tough, flexible solids. This is achieved by adding a hardening agent, ensuring the durability and strength of the final product.

1. Pop Riveting: This method involves using rivets to mechanically connect fibreglass components. 2. Bolt and Nut Assembly: This classic method allows for a strong and removable connection between fibreglass parts.

1. Marine Applications: Vesconite is ideal for marine uses due to its durability in moist conditions. 2. Non-Shrinkage: It does not swell or seize, maintaining dimensional stability. 3. Longevity: The material remains hard, ensuring a long service life. 4. Low Friction: Vesconite features low friction characteristics, which helps in reducing wear. 5. No Asbestos: It does not contain harmful materials like asbestos, making it safer for the environment and users.

To ensure sufficient adhesion, follow these steps:

1. Clean the Surface: Start by thoroughly cleaning both surfaces to remove dirt or oil.
2. Surface Preparation: If the surfaces are smooth, sand them lightly to create a more textured area for adhesion.
3. Base Coat: Apply a thin base coat of adhesive to ensure proper bonding.
4. Thin Layer Application: Use a thin layer of adhesive, as too much can weaken the bond.
5. Adhesive on Both Surfaces: Finally, apply the adhesive to both surfaces to maximize contact and cohesion.

To test the earth system of an electric fence, follow these steps:

1. Short the Live Line: Begin by shorting out the live fence line to the ground.
2. Activate the Energizer: Switch the energizer on to ensure it is operational.
3. Measure Voltage: Use a voltmeter to measure the voltage between the ground and the earth spike.
4. Assess Voltage Levels: If this voltage exceeds 200 volts, it indicates an inefficient earth system.

1. Farm Security: Electric fences can be utilized to secure the perimeter of a farm to deter unauthorized access. 2. Temporary Fencing: They can be set up quickly to create temporary enclosures for livestock.

1. Wind Energy: Wind turbines can convert wind power into electricity for fencing. 2. Solar Energy: Solar panels are a popular way to harness solar energy to supply power. 3. Water Energy: Hydro generators can also be employed to supply energy consistently.