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 metal used for fittings in hot-water copper pipes is Brass. This material is favored due to its strength and excellent machinability, which is essential for creating durable fittings that can withstand high temperatures and pressures.

The recommended alloy metal for hammering tools used in explosive atmospheres is Bronze (Beryllium Copper). This alloy does not generate sparks during use, is characterized by low friction, and has a high resistance to corrosion, making it safe for such environments.

Annealing and Tempering are the two hot-working processes that can be used to modify the structural properties of brass. Annealing helps to relieve internal stresses and improve ductility, while tempering can enhance toughness.

Farmers prefer fibreglass troughs because they are light and easy to move around, which allows for flexibility in positioning them. Additionally, they are easy to fix or repair, reducing maintenance costs and efforts.

The resin used in the manufacture of fibreglass products is defined as low viscosity fluids that can transform into tough, flexible solids upon curing. This transformation occurs through the addition of a hardening agent that facilitates solidification.

You can join fibreglass parts using the techniques of Pop riveting and Bolting and Nutting. Another common method is using an additional layer of fibreglass to create a bonded joint.

Vesconite is the preferred material for bushes for several reasons:

1. It is ideal for marine applications due to its water resistance.
2. It does not swell or seize, maintaining its integrity over time.
3. Vesconite retains its hardness, ensuring durability.
4. It exhibits low friction properties, which can help in machine efficiency.
5. The material does not contain any harmful asbestos, making it safer to work with.

To ensure sufficient cohesion when applying an adhesive, follow these steps:

1. Clean the surface properly to remove any contaminants.
2. If the surface is slippery, consider sanding it to increase texture.
3. Apply a thin base coat of adhesive if the surface is porous.
4. Use a thin layer of adhesive for even distribution; a thick layer may compromise the joint.
5. Finally, apply the adhesive to both surfaces to improve bonding quality.

When testing the earth system of an electric fence, the following procedure should be adhered to:

1. Short out the live fence line to ensure safety.
2. Switch the energizer ON to initiate the electric flow.
3. Measure the voltage between the GROUND and the Earth Spike using a meter.
4. Evaluate the readings; if the voltage is above 200 volts, the installation may be inefficient.

Electric fences are commonly used on farms for:

1. Protection and security purposes, safeguarding the property from intruders.
2. Temporary fencing for controlling livestock or creating new grazing areas.

Three alternative energy sources suitable for powering an electric fence are:

1. Wind energy, harnessed using turbines.
2. Solar energy, collected through photovoltaic panels.
3. Water energy, utilizing hydroelectric systems.