Faced plywood can work just fine for the exterior. Make sure the plywood
has not been treated with anything that could impart a bad taste to your
cigars, or seal the exterior from the interior spanish cedar or Honduran
mahogany to prevent the odor from migrating inside the cabinet.

As for sealing the unit, this really depends on the area you live in. If
your in a very dry climate (desert) then you will need a full seal to
maintain 70%. However if your in a medium to full humidity climate then
it's ok to have less then a full seal. Your cigars need a little
circulation anyway which is why it's recommended you rotate them every
now and then, so it's ok not to have a 100% sealed box.

Depending on the size chest humidor you're building you may want to
consider active humidification versus the typical passive units (Oasis
foam etc.). These not only provide circulatory air flow via the
humidification fan, but also prevent over/under humidification via
active monitoring. I used one from Habitat Monitor in my chest humidor
http://pweb.netcom.com/~raptorlp/humidor.html
The link to that company can be found at the bottom of my humidor page
linked above.

Lee
Carter Products Company
http://www.carterproducts.com

Paul O. wrote:
For some time I have wanted to make a chest humi. My question is , can one
be made with a faced plywood? I realize that with any wood that the inside
side would have to be sealed with something to keep the moisture from
ruining it. What are your opinions and experiences here.