Chipped or Cracked Sink
Updated February 20, 2026
Chips and cracks in porcelain, enamel, fireclay, composite, and acrylic sinks range from cosmetic to structural. Small chips fix with a touch-up kit. Larger cracks may need refinishing or replacement.
Overview
A chip in porcelain or enamel exposes the metal underneath, and that metal starts rusting immediately -- spreading under the coating and getting worse. A crack in acrylic, fireclay, or composite can let water seep through to the cabinet below. The fix depends on the material, the size of the damage, and whether it is surface-only or structural (through the full thickness). Small enamel chips repair with a touch-up kit for under $20. Larger cracks, especially fireclay or composite, often need professional assessment. Know your sink material first.
Symptoms
- Visible chip where the coating is knocked away, exposing a different color underneath (white porcelain over dark cast iron, colored enamel over grey steel)
- Rust stains forming around a chip -- exposed metal corroding and spreading under the enamel
- Hairline crack on the surface -- run a fingernail across it to feel if it is surface-level or through the material
- Water seeping through a crack to the cabinet below -- structural failure, not just cosmetic
- Rough or pitted area on composite or acrylic where abrasive cleaners have worn through the surface
- Crack radiating from the drain or faucet holes -- stress points where cracks start from overtightened hardware or impact
Common Causes
- Heavy objects dropped in -- cast iron pots, glass dishes, heavy tools. One drop from counter height chips most enamel sinks. The impact fractures the brittle coating and exposes the metal.
- Thermal shock -- boiling water poured directly onto a cold porcelain or fireclay sink. Rapid expansion cracks the material. Worse in winter, worse on an empty sink. Fireclay is especially susceptible.
- Cumulative impact from daily use -- pots, pans, and dishes banging against the basin create micro-fractures over time. No single impact looks like damage, but it weakens the enamel until a piece chips away.
- Overtightened hardware -- drain basket, faucet, or sprayer mounting nuts clamped too hard against the sink. Excessive force cracks porcelain and fireclay. Cracks radiate outward from the mounting hole.
- Age-related deterioration -- sinks 30+ years old develop crazing (network of fine hairline cracks) from thermal cycling and chemical exposure. Primarily cosmetic but makes the surface rough and prone to chipping.
What You'll Need
How to Fix It
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Identify the Sink Material and Damage Type
First, identify the material. Porcelain over cast iron: heavy, magnetic, dark base when chipped. Porcelain over steel: lighter, also magnetic. Fireclay: solid ceramic all the way through. Composite: dense, stone-like. Acrylic/solid surface: plastic-based, lighter. Stainless: no chips, but dents and scratches. Then assess: surface chip (enamel only), crack through the coating, or structural crack (through the full thickness)?
Tip: Magnet test: sticks means enameled cast iron or steel. Does not stick means fireclay, composite, acrylic, or stainless. -
Repair Small Chips in Porcelain or Enamel
Porcelain repair kit ($10-20). Clean the chip with denatured alcohol or acetone -- all grease, soap, and loose material. Rust? Sand with 400-grit until you reach clean metal. Apply the two-part epoxy from the kit with a small brush. Build up thin layers, each one dry before the next, until level with the surface. Full cure is typically 24 hours before using the sink.
Tip: Color matching is the hardest part. Most kits are standard white. Different shade (almond, biscuit, bone)? You may need a tinted kit. Test on an inconspicuous spot first. -
Repair Chips and Scratches in Composite Sinks
Composite repair kit from the manufacturer or color-matched epoxy. Clean thoroughly. Shallow scratches: 400-600 grit sandpaper followed by mineral oil often restores the look. Deeper chips: fill with color-matched epoxy, cure, sand smooth. Blanco, Franke, and Elkay sell brand-specific kits that match their colors exactly.
Tip: Dull composite sink with light scratches across the whole basin? Light sanding (400-grit) plus mineral oil restores the original appearance. Works because composite is the same material all the way through. -
Repair Cracks in Acrylic or Solid Surface Sinks
Acrylic and solid surface (Corian, Swanstone): fill cracks with clear or color-matched acrylic adhesive. Clean, dry completely, work adhesive into the crack with a razor blade or putty knife. Wipe excess before curing. Sand smooth with progressively finer grits (220, 400, 600) and buff. Solid surface sinks can be fully sanded and rebuffed to remove scratches, stains, and minor damage.
Tip: Solid surface integrated with the countertop? A specialist can refinish it in place -- sand out damage, fill cracks, rebuff to like-new. Often cheaper than replacement. -
Address Structural Cracks (Leaking Through)
Crack through the full thickness with water seeping through is structural failure. Porcelain over cast iron: the base has fractured, repair kits will not help. Fireclay: through-crack compromises integrity. Both need replacement. Temporary measure while planning: clean, dry, apply waterproof epoxy (JB Weld WaterWeld, Loctite Epoxy), full cure. Can buy weeks to months but is not permanent.
Tip: Before installing the new sink, check the hardware. If the crack started at a mounting hole, the same overtightened hardware will crack the new one too. Proper gaskets, manufacturer torque specs. -
Prevent Rust Spreading on Chipped Enamel
Not ready for the full repair? At minimum, stop the rust. Clean the chip, remove existing rust with fine sandpaper or rust converter, apply clear nail polish or rust-inhibiting primer as a temporary barrier. Prevents moisture from reaching exposed metal and stops rust from spreading under the enamel. Stopgap only -- do the full repair as soon as you can.
Tip: Clear nail polish is surprisingly effective. Waterproof, dries fast, invisible on white porcelain. Reapply every few weeks until you do the permanent repair.
When to Call a Pro
Call a pro if the crack is structural and needs replacement, if you want a professional color-matched repair on a visible chip, if it is a high-end fireclay or farmhouse sink worth exploring repair before replacing, if the sink is undermounted (detaching from the counter requires careful handling), or if the damage is near mounting holes and you are not sure about structural integrity.
Prevention Tips
- Sink grid or bottom rack -- single best protection against chips. Cushions impacts from dropped pots, dishes, and utensils.
- Never pour boiling water into a cold, empty porcelain or fireclay sink. Run water first to warm the surface. Prevents thermal shock.
- No abrasive cleaners or scouring pads on porcelain, acrylic, or composite. Soft cloths, non-abrasive sponges. Abrasives thin the enamel over time.
- Do not overtighten drain baskets, faucet nuts, or any hardware against the sink surface. Snug, then stop. Excess force cracks porcelain and fireclay.
- Rubber mat or towel in the sink when handling heavy items (cast iron cookware, large glass). Absorbs impacts.
- Repair chips promptly on enameled cast iron. Unrepaired chip lets rust form and spread under the enamel -- small repair becomes a big one.