Raw materials for our clay recipes are delivered to Boston Valley in dry powder form in supersacks weighing 2200 lbs. We source all the clays used from North America and blends 2–3 clays in each recipe. Each recipe is dry-batched according to the current formula by a computer-controlled cart that is calibrated quarterly. After the proper amount of each ingredient is weighed out, the batch is placed in a muller-mixer where it is first dry-blended, and then the proper amount of water is added and the batch is thoroughly blended. This mixture is dumped into a souring bin where it is allowed to age for at least 24 hours before use so that the water has time to hydrate the raw materials at a molecular level to increase the plasticity of the clay. Once aged, the clay is extruded into a slug for use in the hand pressing or RAM pressing operation or extruded through a steel die into a specific profile.
All masonry units, no matter their forming method, pass through the finishing department and the hands of a Boston Valley sculptor. Any textures are added in the finishing department so that the new piece replicates the historic sample or approved new construction unit in all aspects of shape and texture. Extremely detailed ornament is carved into or onto the units by our talented sculptors. The finishing department is also responsible for adding any slots for anchoring, identifying mortar indents, and making any final modifications before the piece is dried.
Upon completion in the finishing department, units are loaded into the driers. The driers are temperature and humidity controlled to ensure a proper drying rate and thus prevent cracking. Those projects that have specified a glaze finish are then taken to the glaze application department. The glazing department utilizes various application techniques to achieve the range of finished appearances and topographies required to replicate historic glaze finishes or create new unique finishes.
Our facility houses six large gas-fired kilns. Because the product can vary in volume from piece to piece, Boston Valley has the capability to customize our hearth structure when needed. This allows us to provide such a wide range of custom shapes, with depths that vary from as thin as 5/8″ for Guastavino tiles, all the way up to 4-foot wide masonry units. As with any ceramic product, terra cotta units demonstrate a color range when fired because of the small differences in temperature from the top to bottom and left to right of the kiln. These variations are inherent to this natural material formed of substances mined from the earth., adding to the beauty of the finished product.
After firing, almost every unit manufactured at Boston Valley Terra Cotta spends time in our sizing department. Masonry units are typically made oversized on their non-finished face sides so that they can be cut to a clean and accurate dimension post-drying and firing. Boston Valley uses large format, laser-aligned, diamond-edged wet gantry saws to cut blocks to the width or height specified on the approved shop drawings. The scrap generated from this process is recycled with our own pulverizing equipment and put back into the manufacture of additional terra cotta units.
Stay up to date with Boston Valley on new projects, restorations, events, and more.
You can unsubscribe at any time.
sales@bostonvalley.com
1.888.214.3655
Find a Rep