Method of making double-walled structure, and structure formed by the method

A disposable double walled structure of pulp material, comprising;

• an inner wall portion surrounding a product space presenting a cross section and extending along an axial direction, perpendicular to the cross section, between first and second axially spaced apart portions, wherein one of the axially spaced apart portions forms a closed end and the other one of the portions forms an open end, such that the space defines an axially open receptacle, and an outer wall portion at least partially surrounding the inner wall portion;
• wherein:
• a circumference of the product space is continuous in the sense that it does not present any joint, the inner wall portion and the outer wall portion are formed in one piece of material, a first transition between the inner and outer wall portions is formed by a continuous fold of the one piece of material, extending as a continuous transition around the open end of the receptacle;
• the inner and outer wall portions at least partially overlap as seen in a direction perpendicular to the axial direction, a second transition between the inner and outer wall portions is formed by a joint between the inner and outer wall portions at the axially spaced apart portion that forms the closed end, and the insulating space is formed between the inner and outer wall portions from the first transition to the second transition.