Abstract: Shop primer compositions having improved properties comprise (a) fillers and pigments, at least 25 wt. % of which have conductive properties; (b) zinc powder in a weight ratio to fillers and pigments between 1:16 and 1:1; wherein the zinc, fillers and pigments are milled to a sufficient fineness; (c) anti-settling agents; (d) optionally, thickening agents; (e) a silicate-type binder, in an amount such that the weight ratio of the SiO.sub.2 content of the binder to the zinc, fillers and pigments is between 1:4 and 1:16; and (f) solvents.When using the shop primer compositions of the present invention, the welding properties are improved and the health hazards during welding are reduced, without having to remove the primer layer at the welding area. The primer coatings are compatible with the welding techniques generally used in the heavy steel construction industry, including MIG/MAG welding in 3F position.