The present disclosure relates to methods for producing spark plugs and/or spark plug components, and a capsule which may be used to produce a spark plug or spark plug component. The capsule may include a housing of a material which is unstable when heated a threshold temperature, and the capsule may further be filled with one or more powders, whereupon heating of the capsule of the housing may break down and the powders may be sintered or fused into a resistive body. The presently disclosed method may simplify and/or reduce the cost of producing spark plugs using known methods of inserting powdered precursor materials.