Bathtubs are made of various materials, each with its own pros and cons. The most common materials used to make bathtubs are:

• Fiberglass: Fiberglass is a reinforced plastic that is formed into layers and then molded into a bathtub shape before being coated with a layer of gelcoat resin. Fiberglass tubs are lightweight, easy to install, and relatively inexpensive. However, they are less durable than other materials and can flex, making them less stable to stand on.

• Porcelain over Steel (Enameled Steel): Porcelain-enameled steel is a common and often inexpensive option. It is constructed of steel sheeting that is coated with porcelain enamel. Porcelain bathtubs maintain a nice sheen and luster, and their surfaces are very smooth, maintaining an old antique aesthetic. The coating in the tubs is naturally resistant to scratching, and cleaning is easy to maintain as a mild detergent or baking soda with warm water will usually knock out any tough stains in a porcelain bathtub.

• Acrylic: Acrylic is a costlier material than enameled steel and fiberglass but more durable. It can be used to create a myriad of designs in different colors. This bathtub material is formed by heating a mixture of materials until the desired product quality is achieved. The product is then molded into the bathtub shape and reinforced with fiberglass. Acrylic tubs are lightweight, easy to install, and have great heat retention. However, they are sensitive to abrasive chemicals and can be prone to scratching.

• Cast Iron: Cast iron tubs are made of molded iron coated with porcelain enamel. They are one of the most durable bathtub materials available and have a thick layer of enamel that resists chipping, scratching, and denting. However, they are very heavy and may require structural reinforcement of the floor during installation.

• Stone: Stone bathtubs are made of natural stone, such as granite or limestone, or a composite material that includes ground-up stone and resin. They are very sturdy and non-porous, making them easy to clean and maintain. They also have high heat retention, which makes them enjoyable to use. However, they are heavy and expensive.

• Wood: Wood is rarely used to make bathtubs because the material is porous, and its pores can absorb water. This makes it more difficult to clean and maintain. However, wooden bathtubs can be very aesthetically pleasing and provide a unique look to a bathroom.

In conclusion, bathtubs can be made of various materials, each with its own advantages and disadvantages. The choice of material depends on factors such as cost, durability, maintenance, and aesthetics.