| CPC F24F 13/082 (2013.01) [B29C 41/20 (2013.01); B29C 44/18 (2013.01); F24F 13/06 (2013.01); B29C 44/36 (2013.01); B29K 2075/00 (2013.01); B29K 2105/0058 (2013.01); B29K 2995/0015 (2013.01); Y10T 29/49158 (2015.01); Y10T 428/233 (2015.01)] | 14 Claims |

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1. A plug apparatus for sealing an interior of a duct in a process for forming an insulated register box, the plug apparatus comprising:
a frame;
a shaft extending outwardly of said frame, said shaft having a cap at an end opposite said frame;
a plurality of layers of flexible material radiating outwardly of said shaft adjacent to an end of said shaft opposite said frame, said plurality of layers of flexible material adapted to have an outer periphery bearing against an interior surface of the duct;
a washer positioned on said shaft and interposed between the cap and said plurality of layers of flexible material, said washer being rigid, said washer having a diameter less than an outer diameter of said plurality of layers of flexible material; and
a fastener affixed to said shaft on a side of said plurality of layers of flexible material opposite said washer, said fastener having a surface bearing against said plurality of layers of flexible material, said fastener having a diameter less than the outer diameter of said plurality of layers of flexible material.
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