viscous form e g by heating and the insert section 4 of the washing container 2 is pressed into the viscous plastic 5 with adhesive properties so that the latter spreads out in the grooved recess 6 of the assembly base 3 thus forming a watertight connection between the assembly base 3 and the insert section 4 according to an advantageous embodiment of the invention the insert section 6 is provided with open spaces 7 as shown in fig3 so that the viscous plastic 5 with adhesive properties is pressed through these open spaces 7 during pressing of the insert section 4 and thus forms a positive connection with the insert section 4 of the washing container 2 after the plastic 5 with adhesive properties hardens in assembling the washing container 2 care should always be taken that the processing of the plastic 5 with adhesive properties within the grooved recess 6 progresses such that no air chambers develop which might negatively influence the water tightness as shown in the arrangement according to fig4 in a further advantageous embodiment of the present invention a step 8 is made in the side walls and rear wall of the washing container 2 which is arranged and formed such that after assembly a substantially flush surface can be perceived in the interior of the washing container by way of advantage and aside from aesthetic considerations the step 8 also serves as justification during the assembly process since the washing container 2 can be set on the step 8 while the insert section 4 is inserted into the viscous plastic 5 with adhesive.