There are many different makes and models on the market and they are made from an equally varied amount of materials. Many chalk lines are made from die-cast magnesium and are often given a coat of paint to help resist corrosion.
Die-casting
Die-casting is a metal casting process that forces molten metal at high pressure into an accurately machined mould cavity.
Magnesium
Magnesium is a chemical element known as an alkali earth metal. It is shiny grey in appearance and is used in manufacturing of chalk lines because it is lightweight (75% lighter than steel), has high impact resistance, and excellent strength to weight ratio.
Other models of chalk line may be made from ABS (Acrylonitile Butadiene Styrene).
ABS stands for “Acrylonitile Butadiene Styrene” and is a common plastic used to make chalk line boxes as well as in many other manufacturing processes because it is lightweight, tough and impact resistant. Children’s building blocks, for instance, are commonly made from ABS.
Aluminium
There are also some models of chalk line box that are made from die-cast aluminium.
Aluminium is a chemical element. It is a soft, silver-white, ductile metal that is often alloyed to improve its strength. It is widely used in the manufacturing of chalk line boxes because aluminium alloys are strong, lightweight and durable.
String
The string in a chalk line tool can be made from a variety of materials, typically braided nylon or cotton.
Twisted cotton is type of yarn, consisting of woven fibres and interlocking threads that have been spun together to form a string or rope, increasing its strength.
Braided nylon
Nylon is a silky, synthetic plastic polymer and is one of the most widely used plastics in the world. The individual threads have been woven together in an interlocking braided pattern to increase its strength.
Hook
Stainless steel
The hook that attaches to the end of your string is typically made from stainless steel. Stainless steel is strong, durable and resists corrosion and rust.
Stainless steel is metal alloy that is made by mixing steel with chromium. Chromium gives steel the ability to resist corrosion, rust and staining which ordinary steel lacks. Stainless steel is one of the world’s most widely used and recognised steels.
Crank
Though it may vary from model to model, the crank is typically made from stainless steel as it is the part of the chalk line that is used the most, so needs to be able to withstand wear.
Which material should you choose?
Box
If you are a frequent user, having a chalk line box that can withstand a few bumps and bruises is essential.
A chalk line box made from ABS will be impact resistant, durable and slightly cheaper than its metal counterparts. If you are willing to shell out a few more pounds then an aluminium one may just last a lifetime.
String
A nylon braided string is considered the best string for the job as it is stronger than twisted varieties. Nylon is also waterproof, rot-proof and resistant to mildew.
Cotton string is more absorbent and may produce a clearer chalk line but it may also weaken or snap if exposed to the elements.
Hook
As the hook will often be under pressure, having a sturdy one is essential. Stainless steel is the way to go.
Crank
It is important to have a crank that can withstand a lot of strain, because if that breaks then your chalk line is useless. A sturdy stainless steel crank should give you years of service.