A method of bonding a capillary tube made of a thermally deformable material to a passage in a glass wafer comprising the steps of treating the surface of the capillary tube to render the surface bondable and wettable by a conventional epoxy resin; inserting a support inside the capillary to prevent inward deformation of the capillary during subsequent fabricating steps; inserting the supported capillary inside the port on the wafer; heating an end of the capillary proximate a bottom portion of the port to effect melting of a portion of the heated end of the capillaries; moving the melted end of the capillary into contact with a wall of the port at a desired location for the capillary in the port, thus forming a temporary seal between the capillary and the wall of the port; and introducing an epoxy around the capillary to bind the capillary to the wafer.