Getting the BEST results from Sanding.

For woodworkers, creating something out of wood is more than a hobby, it’s a passion. The process begins as raw, rough lumber. The woodworker shapes it into a beautiful finished piece that is inviting to touch. The whole process is something between geometrical and magical. But the one step in the process that nearly every woodworker hates is, sanding. So here are some steps to achieve that, “oh so smooth finish”, and give the piece the invitation to touch it.

Without a doubt, an electric sander is the way to go to speed up the tedious part of sanding. But there are a couple of different sanders on the market and they can give different results in the final product.

Electric sanders

Palm sander. Beginning at a reasonable price, this sander is a good entry level tool. It takes square sheets of sandpaper. A regular (8×8) sheet of sandpaper, can be ripped into quarters and attached to the bottom of the sander by some means of a mechanical fastener.

The sander moves in a back and forth motion. Perforated holes are to be punched out on the paper to allow some of the dust to be collected in the dust collector.

Because of the movement back and forth, the sander creates and odd swirling vortex in the very center of the sander. As the grit falls off the sandpaper, the grit gets trapped there causing tiny circular scratch marks on the work surface. Also, the sandpaper can wear out from the repetitive movement and either come out of the mechanical fasteners or rip altogether.

Care must be used with this sander on  some projects. Places where wood grain meets at 90 degree right angles, such as the stiles meeting the rails on a cabinet door, this sander can cause cross grain scratching.

In all fairness, it sounds as if i am being tough on this sander. Where it really excels is in corners of projects, such as the inside of a chest.

Random Orbital Sander. This is a level up from the palm sander in many ways. The sander is round and spins in but also does vibrate slightly back and forth. It essentially moves in an elliptical pattern. This movement excels because it never goes over the work surface with the same rotation pattern. That results in minimal scratches left in the wood.

The sandpaper disks come round with the perforated holes already in them. Attaching the disks are easy because most orbital sanders have a hook and loop (like Velcro) means of attaching.

There is still care that has to be used with this sander. Some woodworkers may try to substitute this sander in place of a hand plane or card scraper. The tendency is to lean excessively on the sander in trouble areas of the workpiece. This causes undue wear to the hook and loop pad. The wear on the pad will cause it to not adhere to the disk anymore.

Assuming the project has been planed/card scraped and ready for sanding, here are my steps that will help give you a flawless finish.

  1. Begin with wiping the workpiece clean of any dirt or grit that might be on it.
  2. With a soft lead carpenters pencil  draw pencil lines across the whole surface of the area to be sanded.
  3. Work the sander, going with the grain, back and forth in sections of about 6-8 inches. Slowly work it down the workpiece making sure to overlap the previous section.
  4. Once the piece is sanded make sure all the pencil lines are gone.
  5. Wipe the piece down with a soft brush.
  6. Take sandpaper and wrap it around a scrap block of wood, and go the entire length of the piece using the same grit sandpaper, in this case 80 grit. This helps eliminate any scratches that might have gone across the grain.
  7. Use low pressure compressed air blow off the dust. Wipe down with a clean rag.
  8. Use denatured alcohol and wipe it on the workpiece. Hold a worklight at a low angle to the workpiece and look for any marks or deflects left behind or missed. NOTE- any blemishes must the handled now before continuing further.
  9. Repeat steps 2-8 working through the grits 100 and then 150. 220 grit is optional.

I typically end my sanding with 150 grit. Any ultra smooth finish I can achieve in the top coat finish.

It’s commonly said that sanding a workpiece any smoother that 220 grit will affect the way stain can absorb into the wood. The theory is that the pores of the wood get plugged from the fine sawdust getting into them. Resulting in blocking the stain from absorption.

In a future article I will debunk this myth this and explain what truly causes the lack of stain penetration. Until then……

Keep on Dancin’

Chad Stanton- Professional Furniture Maker