True Blox are a different kind of block. Almost all other sanding blocks in the past were basically the same, there were only a couple of them, and they were just different lengths. They were very general purpose.
There are a lot of different True Blox, 9 different thicknesses, and 7 different lengths. What’s the point, and how do you choose which block to use?
- First, all the blocks with the black handles are for body work and blocking primer.
- Choosing a block is based mostly on how much it flexes, which is determined by the block’s thickness.
- The longer a block is, the more flexible it will be. So a 12” long 3/8” thick block will be pretty rigid, while the same block 22” long will be a little flexible.
- The correct block should take a small amount of tension to form to the shape of the panel.
- The block should do most of the work sanding the correct shape, so choosing one too rigid or too flexible won’t work as well.
- If the center of the block is doing most of the sanding, it’s too rigid.
- If the block seems too loose and the ends are sanding too much, it’s too flexible.
- Most times, several blocks are needed for one panel. It’s encouraged to switch blocks freely until one feels right.
- Usually, the longer the block the better. It should not feel awkward though. It typically shouldn’t be longer than the panel is (the edges will get sanded too much)
- A bigger block does not mean straighter body work. So don’t jump to grabbing the thickest and longest block thinking it will work better.
- The small blocks without handles are for wet sanding. The sandpaper is wrapped around them, and you hold onto the flaps of the sandpaper.