soldering - no no
Got pulled over once because on magnetic buttons on my shirt.
That prompted them to check my hands with the chemical detector.
It gave a positive - going to a conference, I had to do a last minute fix to our demo hardware right before heading for the airport. Two strikes.
Then they started messing with said demo hardware - that had already "passed" the x-ray, but by now she and I were "interesting". Lots of wires, etc. weird stuff. Got to have a behind the doors full undress check. Got through, but learned my lesson. I always get a second look to my carry on, because weird electronics, but this time it went way beyond.