Hi Joe, the weight is all about the same and most of what you are using is sanded off anyway. There are many products on the market sold as a wood filler. As a kid it was called liquid balsa. Today just balsa filler. Light weight spackling is about the best thing I have found in the last decade or two. The tub it comes in weighs more then the product. Sands so easy and when your finished sanding you can add some thin CA and it is hard as stone. Fill a gap then harden and it bonds with the wood. Found in any hardware store. If you pick up the tub and if feels heavy you got the wrong stuff, the tub should feel empty.