EAA Sport Aviation

Spline Blocks

The magic of sandpaper

BY ELLIOT SEGUIN

BODYWORK IS A BLACK art. The magic that happens when sandpaper is applied to a spline is an old-world skill that will continue to be relevant—even in the modern computer-aided shop—regardless what the software guys will tell you. For a process that is so fundamentally simple, the application is terribly individualized. Everyone seems to have their favorite blocking and leveling procedure, and you can spend a lot of time and money trying out all the options and equipment. In my limited ventures I have found a few products that work with my style.

Everyone seems to have their favorite
blocking and leveling procedure, and you
can spend a lot of time and money trying
out all the options and equipment.

DURA-BLOCK

The Dura-Block line of sanding blocks is perhaps the most widely available sanding block. Made of EVA rubber, these blocks are relatively cheap. They come in lots of shapes, they work wet, and you can find them just about anywhere that sells paint supplies. I have a 24-inch block, a 16-inch block, an 11-inch round block, and a teardrop block.

My biggest complaint with these blocks is their generally low stiffness (especially in longer lengths) and that they will take a set during a job. This is fine if you are working a small area or transitioning between several similar curves. However, as the area you are working gets bigger and flatter, and you move to longer and longer blocks, hand position and pressure become critical. For this reason I wouldn’t recommend the longer block (greater than 16 inches) to a green builder.

A lesser complaint is the sandpaper surface is too easily damaged. At some point you will forget to take the paper off at the end of the job. You will have to use a razor blade to remove the paper, and you will damage the working surface of the block, which will affect your block’s sanding surface. However, for the price and availability this block is hard to beat.