This As-Seen-On-TV mini heat sealer is a small and portable device that can restore an already opened bag to its airtight-sealed state. The way it works– it has a battery operated coil that ...

You might have better luck with the Insta Heat Bag Sealer. This compact battery-operated tool uses heat to create a new seal on plastic bags to keep your food fresh, and it’s only $19.99 (reg. $29).

Instead of buying a heat sealer he built his own to cut them down to size. His build starts with a transformer to drop mains voltage down to 9 Volts.