Stopin

Stopin (Formwork Hole Plug)

The Stopin, also known as a formwork hole plug, is a plastic cover designed to block holes in metal formworks during the concrete casting process. This component prevents the escape of material from the mold and stops external contaminants from entering the mold when it is not in use. It plays a crucial role in the molding process by helping to increase the lifespan of the mold and ensuring the quality of the products being produced.

Application in Concrete Formwork

In concrete formwork technology, certain preparation steps must be followed, including creating holes for bolts to pass through the formwork. Typically, a hole with a diameter of 21 to 22 mm is drilled in the metal formwork to allow the bolt to pass through and exit from the opposite side of the mold. The mold is then secured with braces, washers, and nuts to prevent separation during the concrete pouring due to the hydrostatic pressure of the concrete, which behaves like a fluid. Metal formworks can be used more than 50 times, but after several uses, the holes in the formwork may cause concrete or slurry to leak out. To resolve this issue and reuse the perforated formwork where bolt passage is not needed, a simple yet effective piece called the formwork hole plug or Stopin is used. These plugs are made of plastic and can be referred to as “hole stoppers.”

Functionality of the Stopin (Formwork Hole Plug)

The Stopin is a simple yet vital component used as a stopper or seal. It has a direct relationship with the place where it is installed, offering a cost-effective solution for blocking the holes in the formwork where bolts are not required. By using the Stopin, the formwork with holes can be reused in areas that don’t require bolt passage, thereby enhancing the formwork’s lifespan and functionality.

How to Use the Stopin

The Stopin is used to seal holes in the formwork where bolts are not required to pass through. The plug is inserted through the flat side of the formwork and exits from the back (where the formwork supports or stiffeners are located). The convex circular part of the Stopin fits snugly inside the formwork, effectively sealing the hole.

Consumption of Formwork Hole Plugs

The number of Stopins required corresponds to the number of holes in the metal formwork designed for bolt passage, where bolt insertion is not needed. For each such hole, a Stopin should be used to block it.

Important Notes on the Use of Plastic Formwork Hole Plugs

• In addition to sealing formwork holes, the Stopin prevents the leakage of concrete slurry. It is specifically designed for use in formwork holes where bolts with a diameter of 16 mm pass through.
• The Stopin is not suitable for use in formwork systems like tunnel formwork, which utilize bolts with a diameter of 22 mm to secure the formwork and handle the pressure of the concrete.