Certain exemplary aspects of the present disclosure are directed towards dual cavity apparatus and related methods involving hermetically sealing the cavities by evacuating and atmosphere therein, filling the cavity with a gas, and sealing the gas in the cavities. This evacuation and fill approach is carried out through openings that provide access to the cavities. During evacuation of at least one of the cavities through one of the openings, one or more spacers prevent the cavity from collapsing in response to the vacuum force.