http://studweldprod.com/
For those of you not familiar with it I thought I would post this. As part of design work I used to call for a special type of weld stud that looked like it was a stack of bubbles. The receptacle was a two arms spring that caught on the bubbles and held the part the studs were welded to.
The idea may come in handy for someone so I have posted a teaser here.
Lee