Method for forming a hollow plastic product

A method for manufacturing a hollow plastic product, the method comprising:

• forming a reinforce member in a desired shape having a defined welding surface formed with a first hole by injection molding;
• forming a hollow main body by blow molding using said reinforce member as an insert, thereby having said reinforce member integrally formed with said hollow main body and having a portion of said hollow main body extended into said first hole in the shape of a mesa when blow-molded such that said mesa-shaped portion has an outside surface exposed in said first hole and flush with said welding surface;
• thermally welding a top end surface of a connector pipe to said welding surface and also to an outer peripheral portion of said outside surface of said mesa shaped portion;
• and
• forming a second hole in said outside surface of said mesa shaped portion to be aligned with said first hole, thereby forming a fluidic communication passage between an interior of said hollow main body and an interior of said connector pipe and defining a first welded film section between said welding surface and a first corresponding portion of said top end surface and a second welded film section, which is contiguous with said first welded film section, between a remaining portion of said outer peripheral portion of said outside surface of said mesa shaped portion and a second corresponding portion of said top end surface.