If you want to reproduce the results of coded aperture, or color-filtered aperture, you need to disassemble a lens to put in some masks. There are some documents you need to have before you start to do it,

canon lens parts catalog
http://www.f20c.com/stuff/canon/partslist/

If you want to disassemble a simple lens, like EF 50mm F1.8 II, check out this tutorial,
http://www.ejarm.com/photo/ef5018iidis/