Most countertop failures do not happen on the straight cut. They happen at the sink cut-out and at the edge — the two places where stress concentrates and where a shortcut shows up months later.
A sintered stone countertop is a large, thin, very hard panel with holes cut in it. Treat it like granite and it will punish you: square internal corners, unsupported overhangs and dry polishing are the usual suspects. The rules below are the ones fabricators learn after their first cracked top.
Never leave a square internal corner on a sink or hob cut-out. Drill or radius each corner to at least 5 mm — a sharp corner concentrates stress exactly where the top is weakest, and the first hot pan or heavy pot can start a crack there. Cut the opening, then finish the corners before any polishing.
While cutting, the piece inside the opening must stay supported so its weight does not lever the slab open at the corners. The same goes for the finished top: overhangs beyond the cabinet need corbels or steel brackets sized to the overhang, not just adhesive.
An eased edge is the safest default — fast to make and hard to chip. A pencil or half-bullnose softens the look without much extra work. A mitred edge gives the thick, solid look buyers love, but the mitre joint must be cut dead straight and bonded with a colour-matched adhesive; a gapped mitre is the first thing a buyer notices.
Dry polishing heats the edge and can open micro-cracks you will only see after installation. Polish wet, stepping through the grits, and inspect every seam and mitre under raking light before the top leaves the shop — on site, fixes cost ten times more.
Every FosBuild quotation can include the factory's fabrication parameters for the exact slab you ordered.
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