# 1995 Edinburgh
This investigation was initiated because the producers, users and testing institutes of the same PE compound recommended different procedures for butt fusion. The major difference was in the pressure to produce the weld. The difference was obviously reflected in the shape of the fusion bead as shown in Figure 1.
The laboratories could find no significant difference in the short-time tensile test between different fusion procedures, but found that the impact strength and the reproducibility of the fusion bead (aspect) was better for low-pressure fusion.