A lithography-free method to produce microfluidic channels for imaging applications is described. Silica microcapillaries, with either circular or square cross-sections, are embedded in the surface of a polydimethylsiloxane (PDMS) base for imaging studies of flow and electrokinetics within a straight channel. Successful production of the devices relies on precisely timing the assembly process. This timing is identified by an in situ elasto-capillary thinning experiment on PDMS; a rheological study supports the use of these measurements. The assembled devices are characterized using atomic force microscopy (AFM) and bright field microscopy.