Concrete Countertop Undermount Sink Form. I put it up on sawhorses so I could finish it. For a under mount sink knock-out, you may even want to use a release agent.
Much like a sidewalk or patio, the wet concrete is poured into forms, finished on top with trowels, then left to cure. Given that undermount sinks are often used with stone and concrete countertops, affixing. Allows adjustable anchor points to secure an under mount style sink to a concrete countertop.
Concrete countertops are durable, heavy and strong enough for an undermount sink.
Will conform to most undermount sinks.
For tight radius corners, sink form can be heated with a blow dryer or heat gun to soften the plastic so it bends easier. NOT well suited for laminate or tile. I would prefer to do a pour in place, with an undermount sink. your advice is greatly anticipated and appreciated.