Born in Rustenburg, Oltmann graduated from the then University of Natal with a BA (Fine Arts) and later an MA (Fine Arts) from the University of the Witwatersrand, Johannesburg, in 1985. He lives and works in Johannesburg.

When Oltmann was commissioned to interpret the RMB logo for their Sandton head office foyer, he adopted his customary process of fabricating by way of weaving forms in wire. He chose aluminium, brass and steel wire as his medium. 

The lions and keys were interpreted in relief and were attached directly to the facing walls behind the reception desk. The hand weaving of the wire involves a process of coiling and stitching. He uses a thicker gauge wire around which thinner sections of wire are coiled, not unlike processes of basket weaving. He uses pliers and wire cutters to work with the wire but do most of the coiling and weaving by hand (without gloves, as they tend to get in the way).

"While my wirework is labour-intensive and time consuming it is also meditative and therapeutic."