I cam across a new (for me) piece of hardware called a rivet nut. We were working on a light-box and discussing ways to connect the milk white acrylic to the aluminium channel, and the rivet nut was suggested, after I brought up weld nuts.
So I looked up rivet nuts, and they are interesting little pieces of hardware, useful in a variety of situations.
Check out this sight for more information: http://www.rivetnuts.com/
At the bottom of their page they have an instruction graphic to show you how they work.