The coating thickness distribution from a rod-fed electron-beam source was investigated for three modes of evaporation: (1) high vacuum evaporation, (2) evaporation at a 2–70 mTorr pressure of argon in the substrate chamber (i.e., “pressure plating”), and (3) evaporation at 1–20 mTorr pressure of argon and with 3–7-kV dc bias applied to the substrates (i.e., “ion plating”). The source used a 5.1-cm-diam 304-L stainless steel rod as the evaporant and, at a nominal power of 60 kW, had apparent deposition rates above 25 μ/min at a 32-cm source-to-substrate distance. Experimental results indicate that there is a marked change in the thickness distribution when deposition takes place at increased pressures, with the over-source coating thickness at 70 mTorr being almost five times as thick (2.92 vs 0.66 mm) as those coatings deposited at 4×10−5 Torr. The results also indicate, for high evaporation rate sources, that the thickness distribution is not influenced by the application of a high voltage bias to the substrate during deposition but is influenced by ambient pressures in the region of the substrate.