API 936 allows for the use oftest panels with enclosed sidesinstead of mesh basketswhen the dimensions exceed 18 in. x 18 in. x 4 in.This substitution provides adequate confinement and stability for larger samples during casting and curing, helping maintain uniformity and representative test integrity.
Wire mesh baskets are typically preferred for smaller, lighter samples, but for larger mock-ups or when vibration is involved, fully enclosed forms prevent edge erosion and deformation during casting and handling.
Reference:
API Std 936, Section 7.3.1.1 - "For samples greater than 18 in. × 18 in. × 4 in. (450 mm × 450 mm × 100 mm), solid-sided molds may be used instead of wire mesh baskets."