Building Your Own Sanding Blocks
High-density foam sanding blocks are great for sanding filler and primer. However, they can get expensive, and the cost alone can have you second-guessing yourself when it comes to modifying them. Mark Simpson shares a great tip that will help you create custom foam sanding blocks at a fraction of the cost. Using simple hand tools, Simpson modifies foam yoga blocks to create custom sanding blocks for almost any need.
Great idea with the Yoga blocks. One thing to mention is a flat surface on the block. The commercial Dura blocks are not always flat on the bottom and it will change with use. I use a flat piece of laminated glass and stick a length of sandpaper to it and sand my blocks. Any good known flat surface will work. my buddy uses a piece of 1/4 inch aluminum plate. It is amazing to see how imperfect your blocks are when you start to sand them. Check your flat surface with a straight edge.