If you must use a sealer I'd find a good FDA food approved cutting board
sealer of something that is odorless as you really don't want to leave a
residual odor that could effect your cigars as plenty of finishes will.
Most solid wood humidors have no finish on the interior for just this
reason. Your best bet would be to make sure all the joints are fully
glued with a high strength filling glue like gorilla glue. This should
provide an adequate seal for the cabinet, and as long as the interior
spanish cedar is well fit it should work just fine. You could go the
extra step and silicone all joints but as long as your joints are all
fully glue sealed this shouldn't be a necessity.

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

Paul O. wrote:

Thanks for the info.My thoughts were, if ply was useable, to go to the big
lumber store here and get a good faced ply and treat the interior with a
good wood sealer and silicon all the interior joint edges before putting the
cedar in.As far as the outside, my finish of choice at the moment is wipe on
poly, however that may change depending on what faced ply I decide to use.
Currently making stuff out of red oak and may stay with that to match other
projects I want to do in oak. But we will see, I would kinda like to do
something in a nice dark wood tho. Thanks again.