It is a butt joint design with parent material forming a lap joint at the base to act as a stop/backup (full pen into stop). This is a new job. Both parent material and filler material were analysied for presence of oxide. Both came back negative. The entire weld machine along with tooling are in a clean room (not sure what category). As stated before the "back up" is part of the joint design. Not sure how long the parts sat before weld, our requirement is 4 hours max. .020 filler shim stock is used and placed in the joint prior to weld. The xrays are of preproduction parts. Production is the next go around. Yes, there has been some cross sections made, but no xray of the samples. That was probably our biggest mistake, due to the chance of not taking a xsection on a void. I can email pictures of the pores if that will help. Size of the pores were not measured yet, mainly because they are so close together that they count as one. The shape is typically a teardrop shape were the narrow end is pointing up twards the outside surface and max dim is appx .050 inch. Wire is added due to the low silicone content in the 6061, cracking would occur otherwise. The joint was designed to be EB welded from the beginning. The joint is .250 deep and .020 wide (filler material thickness) for an aspect ratio of 12.5. This is my first time using the forum and was not sure what to expect. Thank you for your responce and good questions. Hope that the above helps you understand our problem better (feedback is only as good as the information provided). Also can email a picture of the joint design, send me an email at bmdegrow@raytheon.com so I may reply with pictures.

Regards
Brad DeGrow