Not necessarily go weld it together, but they should be going and spending time with the welders. Ben Rich’s memoirs from the Skunkworks talks about this a fair

Not necessarily go weld it together, but they should be going and spending time with the welders. Ben Rich’s memoirs from the Skunkworks talks about this a fair bit. Around there, having the engineers close to the fabricators was one of their central tenets, and the engineers did occasionally roll up their sleeves in the shop. With the SR71, at one point when they were fighting with a nasty engine problem, Ben himself was going to go up on a flight so that the pilot could show him what was happening.