What is the function of a bonding agent when plastering over non-traditional substrates?

What is the function of a bonding agent when plastering over non-traditional substrates?

• A. To improve adhesion between plaster and substrate
• B. To waterproof the substrate
• C. To set faster
• D. To change the color of plaster

Answer: (A)

The main idea is that a bonding agent creates a proper “stick” between plaster and a non-traditional surface. On smooth, non-porous, or chemically inert substrates, plaster by itself won’t grab well, so the bonding agent provides a compatible surface with the right surface energy and texture for the plaster to key into. It acts as a primer that helps the first coat adhere firmly, prevents delamination, and can smooth out minor surface irregularities so the plaster can set and cure properly. It’s not intended to waterproof, speed up setting, or alter color; those aren’t the bonding agent’s jobs.

The main idea is that a bonding agent creates a proper “stick” between plaster and a non-traditional surface. On smooth, non-porous, or chemically inert substrates, plaster by itself won’t grab well, so the bonding agent provides a compatible surface with the right surface energy and texture for the plaster to key into. It acts as a primer that helps the first coat adhere firmly, prevents delamination, and can smooth out minor surface irregularities so the plaster can set and cure properly. It’s not intended to waterproof, speed up setting, or alter color; those aren’t the bonding agent’s jobs.