An edge protector for an electrolysis electrode onto which a thick-electrodeposited copper product is deposited for producing an electrolytic copper product, has an outer surface shape in the central portion thereof which reduces the thickness in that portion to improve uniformity of cooling, and thereby reduce stress cracking as a result of the reduced buildup of thermal stresses. The outer surfaces may be inclined planes or suitable curved shapes that converge from an outer jaw toward an inner jaw. In one embodiment an edge protector is taught such that its top end is angled downward from its center outward at an angle of less than twenty degrees to prevent creation of sharp edges and difficulty in removal. A spreader bar has a shape which enables clamping of the edge protector onto an electrolysis electrode without excessive expansion of the outer jaw, thereby lengthening service life, and easing installation. Both a hollowed and a tapered spreader bar are taught for end insertion.