>We also had much debate over the thickness of plastic to use, and the
>method for sealing the bags. The thicker the bag, the better chance of
>keeping any condensation out.  But it's easier to get the air out of
>thinner mil bags.  As for sealing the bags, we settled on air-tight tape
>ordered from Chiswick, instead of using a heat sealer.  ...We were
>hesitant to use high heat near objects, although that would have made the
>better seal.

Polyethelyne bags (the kind most commonly used) are an adequate barrier for
keeping the air from circulating around the objects. I think they are
useful in preventing moving air from picking up or depositing moisture
rather than their ability to prevent moisture from migrating through the
wall of the bag. As gas or moisture barrier films go, they are the least
effective films. Heat sealing the bags to keep the moisture in is
meaningless, and expensive specialty tapes are also not needed in my opinion.

js
Jerry Shiner
Keepsafe Systems
Microclimate and Oxygen-free storage supplies and solutions
www.keepsafe.ca
toll-free 800 683-4696  fax: (416) 703-5991

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