I've sealed the inside of mine with a glue mixture (I know, 90% of the people say that it is OK, 10% say not to get ANY water near the MDF, and yet people have been doing it that way for a LONG time).

I *might* prime it while I still have the last side still off since it will be easy to do it now, but I won't bother painting it.

Farewell - June 4, 2020