Microwave digestion provides a rapid means of sample preparation in the analytical laboratory. The major disadvantage of this method is the high cost of commercial microwave digestion systems. Modifications to the magnetron timing circuits of an appliance grade oven to make it suitable for sealed vessel microwave digestion are reported. The oven was modified without alteration to the irradiation cavity, and all initial safety features remain intact. Following digestion with the modified oven, NIST Standard Reference Materials (SRMs) were analyzed by inductively coupled plasma emission spectroscopy. The analytical data are similar to the certified concentrations in the SRMs, indicating that the modified oven provides a durable, rapid, cost‐effective means of sample preparation. ©1996 American Institute of Physics.