Before his time in London he served in World War II as a flying boat pilot (Catalina) in the Far East. Scales was commissioned in the RNZAF (Royal New Zealand Air Force) as a Flight Lieutenant and then seconded to the RAF. He saw service in Singapore and, when Singapore was overrun by the Japanese, he flew to Java to continue fighting from there. When Java was also occupied he was held as a prisoner of war by the Japanese on Java for three and a half years until liberated at the end of the war. While in camp Scales showed his talent as a caricaturist by contributing to an in-camp newspaper called 'Mark Time'. Some of these 'Campicatures' were buried and saved by returning POWs at the end of the war and found their way to the Imperial War Museum in London. While being held as a POW Scales also found the time to escape from prison camp and, along with some fellow-escapees, designed and began building a boat with the intention of sailing to Australia. The Japanese waited until the band of men were low with dysentery before coming to pick them up and take them back to prison camp.