A delay unit (10) comprises a timing strip (14) and, optionally, a calibration strip (20) deposited on a substrate (12). The timing and calibration strips comprise energetic materials which optionally may comprise particles of nanosize materials, e.g., a fuel and an oxidizer, optionally applied as separate layers. A method of making the delay units comprises depositing onto a substrate (12) a timing strip (14) having a starting point (14d) and a discharge point (14e) and depositing onto the same or another substrate a calibration strip (20). Timing strip (14) and calibration strip (20) are of identical composition and are otherwise configured, e.g., thickness of the strips, to have identical burn rates. The calibration strip (20) is ignited and its burn rate is ascertained. The timing strip (14) is adjusted by an adjustment structure to attain a desired delay period, preferably on the basis that the burn rate of the timing strip (14) is substantially identical to that of the calibration strip (20) and ascertaining the burn rate of the calibration strip. The adjustment may be attained by one or more of providing the timing strip with jump gaps (164), an accelerant or retardant (166a, 166b), completing the timing strip with a bridging strip (14c), or establishing a selected effective length of the timing strip by positioning one or both of a pick-up charge (16) and relay charge (18) over a portion of the timing strip.