Evaporating Basin, Flat Form

Quick Answer: A flat form evaporating basin is a shallow, flat-bottomed laboratory dish with a pouring lip, commonly made of glazed porcelain, used to concentrate solutions and recover dissolved solids by evaporation on a hot plate, sand bath or steam bath.

A Flat Base for Flat Heaters

Evaporation is fastest when the liquid is spread thinly over a wide area. The flat form basin does this with low walls and a broad, flat floor. The flat base also sits firmly on a hot plate, a sand bath or the bench, where it takes heat across its whole underside, and it needs no ring or triangle to stay upright.

Its round-bottomed counterpart, the round form evaporating dish, is shaped for heating over a gauze or a water-bath ring, where a curved base sits well and heat spreads out from one spot. Choose the flat form for hot plates and for leaving solutions to evaporate slowly at room temperature to grow crystals, and the round form for burner and water-bath work.

Porcelain is the usual material for evaporating basins because its glaze resists acids and it tolerates heat well when warmed gradually. The listing does not state the material, capacity or diameter of this basin.

Specifications

Applications

• Evaporating salt solutions on a hot plate to recover the solid.
• Leaving saturated solutions to crystallise slowly at room temperature.
• Concentrating plant extracts or other solutions on a steam or sand bath.
• Drying wet solids spread thinly in an oven.

Care & Handling

• Start with gentle heat and raise it slowly; a cold basin on a hot plate at full power may crack.
• Stop heating before the last of the liquid boils away, to avoid spitting.
• Soak dried-on residues in warm water rather than scraping them.
• Stack basins with a paper towel between them to protect the glaze.

Why Choose LabEquip

Chemistry teaching labs, pharmacognosy departments and food labs evaporating extracts use flat evaporating basins on hot plates every day. LabEquip lists them in General Lab Products; ask about capacities through the contact page.

Frequently Asked Questions

What is the difference between a flat form basin and a round form dish?

The flat form has a flat base that sits on hot plates, sand baths and benches. The round form has a curved base that suits a gauze, a triangle or a water-bath ring.

Can a flat evaporating basin be used on a hot plate?

Yes, that is its main advantage. Start on a low setting and increase gradually, since a sudden temperature change can crack porcelain.

Why stop heating before the solution is dry?

Near dryness, crystals form a crust and the last liquid boils under it, making the solid spit out. Stopping early and letting the residue dry with gentle heat avoids losses and burns.

How can large crystals be grown in the basin?

Make a saturated solution, pour it into the basin, cover it loosely with filter paper to keep dust out, and leave it undisturbed. Slow evaporation at room temperature gives larger, better-formed crystals.

Is a flat evaporating basin suitable for acids?

Glazed porcelain basins resist most acids, including hot mineral acids. Hydrofluoric acid and hot concentrated alkalis should not be used in them.

How do I evaporate a solution safely on a steam bath?

Set the basin on the rings of the steam or water bath so its base is heated by steam, top up the bath water as needed, and never let the bath boil dry. Steam heating stays below 100 °C, so heat-sensitive residues do not char.

Last Updated: September 2026