At work it sounds like we will need to begin a quality control process to inspect welds in refurbished equipment but I know very little about radiographic weld testing. Are there any manufacturers of portable weld testing machines you guys could recommend? Are there limitations to how portable units can be used? Like if I'm trying to scan into a 3" thick weld, are there portable units that can do that or is there a general rule of thumb for max material thickness? Also do all radiography testers require a film of some sort to be held on the other side of the weld?