The Air Force adopted the Navy's job classification training regime under the name of Rivet Work Force. This killed craftsmanship and quality. The Navy has vastly different needs and different limitations of space. The Air Force thought they could join crafts that had an average four year apprenticeship (one of which was already a triple craft) and force train them to journeyman level in less than two years.
It worked okay on the machinist side, but the welder/heat treater/electroplater side failed miserably. Staffs and Techs whose welds can pass certification (submitting the best cert of fifty cert attempts each) but whose welding ability would never have gotten them signed off as proficient in the past. Heat treaters who couldn't tell you what regulations they are supposed to follow or how to repair their own equipment (let alone re-brick an oven).
Allowing this has translated over to the contractor side, because QA has never been exposed to real craftsmanship and come from a pool of workers who have never operated at that level. For instance QA at Edwards AFB couldn't tell you how critical proper brushplating of high strength steel is, let alone what regulations cover plating. Heck, they don't know what the welding pubs or heat treating pubs are, and the military who were once here didn't seem to know any of that with only a single exception (who had been an instructor at heat treating school).
Also hiring standards are lax as people try to fill positions on manpower rosters, rather than fill positions with skilled technicians. I understand that you could go a year plus trying to fill a welding position, while waiting for an applicant who has the necessary skills, want's to live in the desert, and loves the craft enough that they would work for the pay just to work on the cool stuff (I took a 20K cut to work here). Still, you should make the wait and get competent craftsman who don't need a couple of years of training to actually be capable of working without supervision or technical help.
Update: Comment left on the site by I and I.
The level of skill in the welding industry, in general, has gone down over the years. Partly due to advances in technology that allow better results with less ability and skill, and partly because the pay is really not that great, and partly because "good enough" and "get 'er done" have replaced "high quality" and "get 'er done right."
On the government side (military and civillian) this is entirely the government's fault because of their incredibly lax QA, and it's seeming enthusiasm for not enforcing compliance of the standards it requires on paper.
On the contractor side this is all over the map, and depends entirely on what contractors feel they can get away with.
Usually it takes a massive monetary loss, or a loss of life (usually more than a couple) for the government to step up on this. Worse, the government tends to blame the contractors lack of compliance (and they are to blame for part of this) without ever recognizing that the government's own lack of QA oversight and willingness to enforce standards is root of the problem.