Understanding metal and plastic watering can materials

The material a watering can is made from affects how it feels to use, how it responds to the conditions it's kept in, and how its surface changes over time. It doesn't determine how well it waters.

This article explains what each material is, what you'll notice in use, and what to expect as the can ages.

 

Galvanised steel

Most of the outdoor Haws range is made from galvanised steel — steel that has been coated with zinc to protect it from corrosion, then painted.

The steel used in Haws outdoor cans is 0.5mm thick. At this gauge, the body has a solid, settled feel. It resists everyday handling without flexing or rattling. The joints are sealed by hand using three specialist sealants, creating a watertight structure.

The paint provides the outer finish and an additional layer of protection. Over time, paint may chip or scratch — particularly at the base and along edges that make contact with hard surfaces. Where the paint is removed but the zinc layer beneath is intact, the zinc continues to protect the steel.

Galvanised steel cans are heavier than plastic cans of equivalent capacity. A full one-gallon can weighs around five kilograms in total.

What to expect over time: Areas of high contact — handles, cross stays, the base — will show more wear than the body panels. The painted surface may mark or stain from water minerals and environmental exposure. This is normal surface change.

 

Hot dip galvanised steel (HDG)

HDG cans go through a different process. Once the can is fully assembled, it is immersed in molten zinc by hand — coating every surface, inside and out, including every seam. The zinc chemically bonds to the steel rather than sitting on the surface.

HDG cans are not painted. The surface that comes out of the zinc bath is metallic and bright, but it begins to change immediately. As the zinc oxidises — a natural process — the surface transitions from bright and reflective to muted, mottled, and eventually a more uniform grey. The rate and pattern of this change are influenced by moisture and handling. No two HDG cans come out of the zinc bath looking identical.

This surface change is not deterioration. Zinc oxide is the protective layer that forms as the zinc reacts with the environment. The can is doing what it's designed to do.

What to expect over time: Brightness will fade relatively quickly. Patches, mottling, and a general greying are normal. Frequently handled areas — the cross stay, handle grip points — may become smoother and brighter through physical contact over long-term use.

 

Brass and copper

Haws brass and copper cans are made from solid material — not a plated steel base. The components are cut and shaped using bespoke tooling, then assembled by hand with fine soldering.

Both materials are corrosion resistant. They do not rely on a zinc coating or a painted surface for protection. From the point of polishing onwards, however, both begin to oxidise. The surface gradually develops a patina — a natural oxidation layer that forms as the metal reacts with moisture and handling.

Early patina may show as slight colour change or uneven surface tone. With continued use and exposure, the surface deepens in colour and character. This is how brass and copper behave; it is not a sign of damage.

At 0.4mm gauge, indoor brass and copper cans are engineered for their scale. They're heavier than a plastic can of the same capacity — that's the nature of the material — but proportional in weight to what they're designed for.

What to expect over time: The surface will change. Frequently touched areas change differently from areas that are rarely handled. This is normal and does not affect the function of the can.

 

Plastic

Plastic cans are lighter than metal cans of the same capacity and respond differently to knocks and drops. Where a metal can may dent under impact, a plastic body flexes and typically returns to shape. Colour is integral to the material rather than applied as a surface coating, so surface marks are usually less visually distinct than on painted metal.

Haws plastic cans are constructed by either injection moulding (assembled from multiple components) or blow moulding (the body formed in one piece with no seams or joints). Blow-moulded bodies have fewer points where a leak could start.

Plastic cans do not oxidise, and their surface does not change the way metal surfaces do. Prolonged exposure to UV light can, over time, cause fading and surface degradation — a consideration for cans stored outdoors.

What to expect over time: The surface will remain stable under normal use and storage. UV exposure over extended periods can cause colour fading and, eventually, surface brittleness.

 

Choosing between materials

Material	Weight	Surface over time	Notes
Galvanised steel	Medium–heavy	Painted surface will wear and chip at contact points	Zinc beneath continues to protect
HDG	Medium–heavy	Changes from bright to mottled grey through oxidation	Normal and expected — not a defect
Brass	Heavy (for its size)	Develops patina through oxidation	Solid material, corrosion resistant
Copper	Heavy (for its size)	Develops patina through oxidation	Solid material, corrosion resistant
Plastic	Light	Stable; may fade with sustained UV exposure	Lighter handling; flexes under impact

 

For guidance on caring for your can as it ages, see How galvanised steel changes over time and How brass and copper change over time.