How to stain and finish raw wood diorama base?

The poly-eurethane completely seals the board and keeps it from warping when you apply the wet celluclay, wet epoxy mud, wet plaster, etc..  I suppose if I weren't putting anything wet on the base, the buffing the stain would be sufficient.

I have found that minwax buffs up nicely after it has dried. No need for a varnish over the top of it.

i usually just take some min-wax or tung oil and take an old sock, dip it into the stain and rub it across/into the wood. let it dry. that's it. then do the same with glossy sealer coat! i find using a sock gives it a nice even coating.

MZ,

I use a quality stain (Min-Wax) and a good water based poly-eurethane.  I always apply two coats over all of the base - top, bottom and sides.  Once the first coat has dried (usually overnight) I lightly sand or steel wool the sides which after the second coat, produces a better shine and overall finish.

In between coats:

Another example after two coats:

Once the second coat has been allowed to dry for a couple of days I mask off the sides with a good quality masking tape (3m Painters Tape works best for me) to prevent any groundwork (I use Celluclay) from working it's way over the sides and sticking to them.

Once the diorama is complete I remove the tape by gently pulling it in a "Down and Away" motion, taking great care not to disturb the edges of the groundwork where they meet the edge of the base. 

Hope this helps,

razorboy

Never mind, I found a tutorial on YouTube...