Abstract: A process and means for joining polyamide parts by friction welding, whereby the particles, called "turnings" formed and expelled from the welded joint are captured. In the production of many containers composed of relatively hard polyamides, having melting points above 250 degrees Celsius, it is necessary to prevent the turnings from falling into the inside of the container. This is particularly true when the turnings cannot be rinsed or sucked from the interior with relative ease or minimal cost, such as when walls, ribs or chambers are present inside the container. In the past, recesses have been provided near the joint to collect the turnings, however, such recesses did not prevent all turnings from being thrown into the interior of the container.

Abstract: A removal-resistant plug or closure for a container has a slide radially extensible beyond the circumference of the plug and container to provide a gripping surface for removal of the plug. With the slide retracted, the exterior surfaces of the plug is smooth and devoid of any gripping surface. A seal attached after the container is filled and the plug inserted is provided by a cavity which extends across a lateral edge of the slide and the adjacent portion of the slide guide in the plug. A marker plate is attached to cover the cavity such that when the slide is moved, the portions of the cavity are misaligned to break the marker plate from the plug to provide a visible indication that the seal has been broken.