It would depend on if scenery material was going to be put around your buildings. If yes on ground covers of one sort or another don't spend the money on paint, use it on some ground foam.

If you don't want to add scenery material then paint.

Ground foam and or parking areas made from some sort of plaster material look way better then paint.

Jack

I'd say at least something to seal it. MDF can be finicky with moisture

My number 1 miss in building my RR on 2-inch pink foam was that I didn't paint the pink foam SOME sort of neutral ground color. Way too many little pink voids to manually clean up, especially around switches, where ballast is thin anyway.

It’s not very big, you could probably cover the whole thing with a free sample, or a cheap can of “bad mix” from the hardware store. 

MDF isn’t much more than highly compressed sawdust. Get it wet with scenery materials and it will swell. It takes paint well, however. A good coat of paint may save you disappointment in the future.

GS

It’s not very big, you could probably cover the whole thing with a free sample, or a cheap can of “bad mix” from the hardware store. 

MDF isn’t much more than highly compressed sawdust. Get it wet with scenery materials and it will swell. It takes paint well, however. A good coat of paint may save you disappointment in the future.

GS

I think he has a good call... swells when wet.. and starts to crumble.

Seal it with paint, urethane, even shellac (who uses that anymore?)  - color is not important on the 'seal' coat, unless it interferes with your landscaping.

Even a paste wax is better than "naked" MDF (remember, the F = FIBERboard)

buying a small amount (< 50 gallons or so) of paint that was returned because it was the wrong color.  They might even add some more coloring to make it palatable for your base scenery and charge a very reasonable price too.

Nick

I'd paint and use the cheap "wrong" paint that you can get at a number of places.  I get my "dirt colored" paint for $5.00 a gallon at the big orange box store.  I have even negotiated paint down to $3.00 per a gallon at the big blue box store.

Go to the home depot and the always have a few gallons of some sort of brownish flat house paint that someone did not like the color of on discount.  You will be done in minutes.  Takes more time for clean up.