Porcelain buchner funnels include fixed perforated plates. Funnels are glazed on inner and outer surfaces except for the rims. Thermal shock resistance - average coefficient of expansion from 20 °C to 200 °C is 3.56 x 10-5 , gradually increasing to 4. 69 x 10-5 at 1050 °C. Every batch of porcelain is heat tested in our factory. Glaze - no softening occurs up to 1000 °C, and it is extremely white. Resistance to chemical action - resistance to acids and alkalis is excellent, except for hydrofluoric acid. There may be some variation in the surface of funnels over 90 mm. Buchner Funnels are handcrafted and will show cosmetic imperfections, but this does not affect the functionality of the funnel. Applications: Cold-filtration to remove lipids or waxes, clarification or plant debris removal, bacterial removal using 0.2 micron membrane filters (90 mm glass holders only), batch processing with manifolds, and ethanol washing.