Bentonite
The best bonding clays for metal casting are sodium bentonite and calcium bentonite. Sodium bentonite occurs naturally in the Western United States and thus is referred to as Western bentonite. Green sand produced with it will have medium green strengths and high dry strength, which increases resistance to erosion of metal but can cause issues at shakeout. Western bentonites are commonly used for steel casting.
Calcium bentonite is mined in Alabama and Mississippi and is thus referred to as Southern bentonite. Calcium is more widely distributed. Green sand produced with Southern bentonite will have high green strengths but low dry strength, causing low erosion resistance and prone to scabbing and other expansion defects.
Most of the available products used for green sand molding are blends of Western and Southern and include specific additives to achieve the desired mold characteristics. In addition, clays absorb water from the atmosphere, so they should be stored in dry conditions.
Foundry Products
We supply the necessary foundry products you need to make a quality casting. Whether you need Metals & Alloys, Melting & Melt Quality, Molding & Core Making, Casting & Shakeout, Finishing & Surface Preparation, or Environmental Compliance products, we have what you need.
About Us
Carpenter Brothers, Inc. is the leading supplier of equipment, consumables, and technical expertise for the metal casting industry. Founded in 1917, by Everett and Milton Carpenter, the brothers were able to use their unique foundry experiences to solve the problem of the day: a reliable sand source. They got their foot in the door by selling natural bonded molding sand, which was mined by hand, loaded into horse-drawn carts, and then delivered to customers. Not only did they sell the sand, but their technical expertise was readily available for all customers, big or small, to help manufacture the best castings. After surviving The Great Depression, Carpenter Brothers, Inc. slowly increased the number of products it distributed and expanded its sales territory into what it is today.
Carpenter Brothers, Inc. has committed itself to its customer's success by providing exceptional service to go along with the superior products and equipment they supply. With multiple warehouses around the United States we can get you the products you need when you need them. Our logistics team can handle getting your order to you by truck, plane, or train. Our technical sales and engineering staff all have experience in the industry, so when you buy from Carpenter Brothers you gain access to all of our knowledge.