Try the technique before you buy with a DIY alternative. Roll a sheet of black card into a cone and place a strip of black or gaffer tape along the seam to hold it securely in place.
在买之前先自己DIY一个，把一张卡纸卷成圆锥型，用电工黑胶粘牢。
2
The reasonable widths of backup strip are experimented with the strength factor of the welded seam for a particular kind of PVC/PES.
PES背贴焊接缝合试验，得到了应力-应变曲线、背贴条宽度、焊接缝合强度系数；
3
The defects will be found in the seam side with ultrasonic inspection but hardly found with X ray inspection as the small diameter spiral pipe production with the split strip steel.