MDF (Medium Density Fiberboard) 3 inches thick. With area dimensions of 20 inches wide by 30 inches long this amount of MDF weighs in at 50 lbs...! As such, the block is still only a fraction of what the weight would be in granite. Total weight standing on the Home Depot brackets with turntable is 80 lbs at minimum..
Method of construction:
4 layers of 3/4 inch MDF cut to 20 x 30 inch rectangles. Layers were glued with contact cement and pressed together with the weight of several paving blocks. After all layers were dry at least 24 hours, I used an orbital sander to block the four ends flat. Several coats of primer sealer were applied to the ends to fill the end grain, hand sanding between coats with a 6 inch board with fine cut sandpaper. Once all areas were visibly flat, I applied two coats of flat black all over, blocking the painted surface after the first coat with more fine cut sandpaper and the six inch board. This was an easy project to do and the MDF was cheap.