Rob S. aka Blitz wrote:
Id like to be able to keep this unit outside as well, so I would have to seal the exterior somehow or use a tarp.
Forget the box and don't stack the trays. Check out our dryer that has been used for over 25 years in the humid upper Midwest. Here's a link http://www.geopathfinder.com/9473.html
We've tried the box types, including one built out of an old refrigerator and the Rodale design built in a barrel shape. None of these designs worked as well for us.
By "skip the box" I meant don't stack the trays. Spread them out so the moisture being driven off the food doesn't have to rise through multiple trays. The design also keeps sunlight from bleaching nutrients out of the food, which is essential for everything except mushrooms. Mushrooms actually increase their vitamin D content with sun exposure during drying, especially if the gills are facing the sun.