HI, I make mosaics generally on MDF and untill now it has been fine mosaicing my design and then just whitewashing the back and sides to finish it off. But recently the MDF I have used has been much less finished off or smooth - not sure why - and if I paint the sides then they just look even more rough? Any tips on smoothing it out a bit and making it look better - or is mosaicing the sides with further the only way? I tend to work with glass sheets rather than tiles so don't have lots of tiles to use round the sides.

Thanks