The Foundary was a factory in Waterford where everyone's grandfather used to work. It was located down by the kay river. They used to pronounce it in this way due to the peculiar gutteral r sound of the old Waterford accent.
'A thing of' is a very Irish way of describing an inanimate object, usually a container or packaging of sorts. Be it down to laziness, or actually not knowing the name of what the object is, this expression has many uses.