Abstract: Various methods are described for assembling and/or coupling heater sections together for assemblage of heaters. The heater sections may be hot or cold heater sections having various geometries, dimensions, and specific electrical resistances. In one method, a cold heater section is assembled onto a pre-fabricated hot heater section with an oversized tube and pre-fabricated insulating cores. In another method, a pre-fabricated cold section is spliced onto a pre-fabricated hot section utilizing pre-fabricated semi-annular insulating cores and an oversized sleeve. In a further method, a first pre-fabricated hot section is spliced onto a second pre-fabricated hot section via an electrically conductive core and an oversized sleeve. These methods allow for the manufacture of stock lengths of hot and cold heater sections, that are then cut to length and coupled together. According to one aspect, the methods reduce tolerance errors in heater length.