Our Technology

Steeped in history using traditional techniques. Techniques handed down from generation to generation. Cast iron enameled tubs have been around for over 150 years, many of them are still in use and in great condition after well over 100 years in service. It is doubtful anyone will be saying this about acrylic or synthetic resin tubs in 100 years from now.

As designers and architects shy away from plastic and synthetic resin bathtubs, cast iron bathtubs are becoming more popular than ever.

At Penhaglion, we offer cast iron tubs with a twist.

Our twist, a process first patented in 1880, is molten metal bonded to the exterior of the casting. This proprietary process allows us to maintain the original markings seen in every casting and highlighting these beautiful, vibrant surfaces with highly polished metals such as copper, brass and lead-free pewter or unpolished stainless steel.

Most of our tubs are sold with no lacquer coatings, allowing the surface to really shine or patina as it goes through life in our client’s bathroom. Not all of our finishes will patina and some will change only very slightly throughout their lifetime, but living finishes can also be easily maintained to hold their original high sheen, mirror like finish.

As in everything we do, we looked back over 150 years for original tub designs. We found these ranged from stunningly beautiful to totally utilitarian. The first such category mainly describes the designs coming out of France between the years of 1850 and 1885.

After designing and producing an entire range of new tub molds, we had to decide of what type of casting we would do. Being traditionalists and very keen to produce only the most characterful tubs, we decided on gravity molding. This is the oldest method for molding and various forms of it stretch back centuries.

Reclaimed black ferrous metal is furnace heated to over 1100 Celsius and poured into the two-piece mold. After cooling and solidifying, the mold is opened to present the bathtub form. Quite often, there will be slag attached to the exterior surface and this will be ground off and cleaned before the tub is taken for enameling.

For enameling, we also employ an age-old technique, first used by a Scottish born American, David Buick around 1880. The first step is to re-heat the tub casting back to 850 Celsius and while in the furnace, sprinkle lead-free enamel powder or frit over the entire interior surface, bonding it to the red-hot iron. The casting is then inspected and allowed to cool for an hour before the hand applied enameling process is repeated. About four or five coats are generally applied to reach our average desired enamel thickness of just under 1/8”.

During all of these cooling and re-heating process, shallow fissures and formations occur on the exterior of the tub, giving each bathtub its own unique appearance.

Before final shipping to us in St. Petersburg, Florida, the exterior of the tub is coated to protect against rust formation during its ocean voyage.

Upon arrival at our workshop, each casting will wait to be ordered. Upon receipt of its order, we take it and remove the rust proofing and immediately apply the first, both protective and decorative layers of molten metal to the exterior. Our proprietary method of performing this task is based on an original patent from 1880, using the same processes later improved upon and perfected from the 1940’s forward in the aircraft, architectural, engineering and aerospace industries.

Depending on our client’s choice of finish, these fabulous hand made tubs are normally ready to ship in 4-8 weeks.