Although manufactured as both ready-mix and dry powder mix products, at the time of use joint (or tape joint) compounds as they are often referred to are wet, thick paste-like materials. The joint compound “mud”, is used in conjunction with a special paper tape to form smooth “invisible” connecting joints when gypsum wallboard is installed during the fabrication of interior wall and ceiling surfaces in home and commercial construction. This compound is also used as “spackle” to finish the slight indentations formed where nails or screws are used to attach the wallboard to wood or metal support structures.
Joint compounds are fairly easy to manufacture and do not necessarily require large capital intensive operations, so producers and formulations are numerous; although large operations offer typical economies of scale.
Joint compounds are generally formulated with fillers of gypsum or calcium carbonate, binders such as starch, vinyl acetate or acrylic resins, bactericides and any host of thickeners, stabilizers and light-weighting additives.
Gel quality attapulgite has been the thickener and viscosity builder of choice for decades in literally hundreds of joint compound formulations. AMI’s brands of gel quality attapulgite are now the most widely used of all attapulgite thixotropes in joint compounds around the world.
AMI produces several grades of material for joint compounds in a range of particle sizes. Typical joint compounds use our selected finely ground gel grade attapulgite. It functions as a thixotropic agent and is used in both the wet and dry forms of joints compounds, providing easy spreading under shear but preventing sag when the shear is stopped. Its efficient and consistent suspension ability provides excellent stability to ready-mix compounds during storage and smooth flow and edge feathering with both types of joint compounds when applied with the tape.