need help with pinholes in weld

[j2100]

thanks for all the advice guys i will be trying anything at this point and will respond if anything finally works

[j2100]

The end caps are stamped out at the machine shop and there is oil residue left on the caps from the stamping process i would assume there is no other cutting process involved.I have been told that the oil left on the caps has nothing to do with the problem but beg to differ.

[j2100]

No the ends are not closed completly, when the machine clamps on the ends then it is closed we also thought that and cut holes in some tubing and did our own test and still got pinholes. both ends are open for the shaft to go thgough. thanks

[j2100]

I am new to this board and have been welding for a few years. Where i work i weld together 5 inch diameter tubing with .133 thick end caps to make rollers. The problem is that when welding the ends on pin holes show up almost all the time and mostly at the last inch of the weld. we use .035 wire lincon...