4 You can see that Craig needed to apply filler to a lot of places on the car even though all the sheetmetal is new. Even with the best sheetmetal on the market, you will still need to use a skim coat of filler to get it perfectly straight. Sanding panels straight would be a pain without a good block to stick the paper on, and Craig uses AFS Adjustable Flex Sander blocks. These blocks allow you to adjust the pressure-to-flex ratio, allowing you to tailor the block to the panel perfectly. For more info on the blocks, check out www.adjustablesander.com.