Gentlemen Microballoons, at least the red ones will show thru the covering if you use light colored covering. I use spackling compound[found at wally world or hardware stores] Get the one the is lite in the box so it will not add more weight.Sands good and is lite colored and does not show thru. When I say lite in the box I mean when you pick up a can of it it will feel lite compared with some others.Bob