We present the results of large‐area (20 cm2) diamond deposition from a scaled‐up stagnation‐flow reactor. The reactor uses a unique nozzle geometry that optimizes reagent gas usage. The premixed acetylene–oxygen–hydrogen flames were operated in a highly strained configuration, allowing uniform deposition of diamond with growth rates exceeding 25 &mgr;m/h. Substrate temperature control and flame stability of the chemical vapor deposition reactor are described. Diamond films were deposited on a molybdenum substrate with a surface temperature of approximately 1200 K and C/O ratio of 1.03. Diamond film growth results are presented, and film uniformity is assessed using micro‐Raman spectroscopy. ©1996 American Institute of Physics.