Ask the Handywoman!
By Kheli Mason, The Handy Woman LLC
Lately I’ve been doing a lot of work with wood. Knotty pine to be exact. Hundreds of board feet of it, making baseboard and door and window molding. It takes a lot of busy work to sand and stain and sand and seal all of this wood, but the results are definitely worth the effort.
You have a lot of time for musing when you are doing this type of task. You have to pay attention and keep an eye on what you are doing as you sand each board with one and sometimes two different grits of sandpaper and maybe even a third in between stain and sealer coats. As I was going about this task, I started thinking about what life was like without sandpaper. I couldn’t
imagine doing this type of project (and so many others) without it. So I set out to learn a bit about this staple of the woodworking, auto-body, floor refinishing, gem-cutting, boatbuilding, and myriad other trades and crafts.
Some of the earlier forms of sandpaper were supplied by Mother Nature. Though I have never felt it before, sharkskin has been used successfully for smoothing rough surfaces. The rough horsetail, or scouring rush, a type of grass found in moist locations, is used as a sandpaper and a traditional polishing material in Japan.
Apparently the first recorded use of sandpaper was in China, in the 13th century. Crushed seeds, shells, and sand were bonded to parchment with a natural gum. Originally sandpaper was known as “glass paper” because tiny particles of glass were used. A fellow in London named John Oakey developed new adhesive techniques and processes that would allow for the glass paper to be mass produced back in 1833. Isaac Fisher Jr. patented the first process for mass manufacturing of sandpaper in the United States in 1834 (I wonder if Oakey knew about that?).
So what is sandpaper, anyway? There is a family of abrasive products called “coated abrasives” and sandpaper, a form of paper where an abrasive material has been fixed to its surface, is part of that family. Generally it’s used to remove small amounts of material from a surface to make it smoother (as I am doing with the pine boards I’m working on), remove a layer of material, or in some cases, to make the surface rougher such as scuffing to apply glue.
Sandpaper comes in many different varieties. There are sheets, discs, rolls, belts, adhesive, or hook and loop-backed. There have to be many varieties due to the wide array of tools and machines that use the sandpaper. Many of us have orbital hand or palm sanders, some using round discs of sandpaper, others using ¼-sheets (from a full 9 X 11 sheet). Belt sanders can range from hand-held portable to large industrial sanding machines. Floor sanders can use large belts or multiple discs. Oscillating roll sanders are found in many woodworking shops, and utilize a sanding tube similar to a cardboard paper towel roll.
The sandpaper grit, or coarseness, depends on the task the sandpaper is used for. For instance, I am using 220 and 320 grit papers to smooth my pine boards before and after staining/sealing for a smooth finish. The lower the grit number the coarser the sandpaper will be. The higher the number the more fine the smoothing result. Grits can range from 40 (very coarse) to over 2000 (very, very fine). Some grits are even termed ‘fine micron’ or micrometer level (now that is smooth). It all depends on the project at hand.
What is the grit made of? The abrasives used to make sandpaper, again, depend on the project. The most common with the widest variety is the aluminum oxide grit. This type can be used on metal (auto body work) or wood. Chromium oxide is used for extremely fine grits; alumina zirconia is used for machine grinding; silicon carbide, is commonly used in wet sanding applications; even garnet used in woodworking emery and to abrade or polish metal; and flint though this is not commonly seen anymore.
Finally, a word on safety. Sanding, in effect, turns whatever you are sanding into dust: tiny particles which are easily inhaled. It would be a wise idea to wear a dust mask and safety goggles to protect yourself from possible problems. It wouldn’t be a bad idea to wear gloves as well, especially if you are using sanding machinery. Even a little palm sander can cause a painful abrasion if it inadvertently contacts the skin. And a belt sander, even worse (I wouldn’t know about that, of course. I read about it though).
For your next project, take a moment or two to think about the final result you are trying to achieve. Choose your grit and sandpaper variety wisely. Trying to knock down a very rough surface of a board with a 220 grit paper, or one that has been used to the point of being dull, won’t give you the results you are looking for. Start coarser (with, say, a 150 or 180 grit) and work your way toward fine to achieve a smooth surface with less hassle and elbow grease in the long run.
Enjoy your project, and while you are sanding away, musing, say a word of thanks to good ole’ John Oakey that you aren’t having to use crushed shells, seeds, sand and gum to sand your board smooth.
With over 20 years’ experience in Home Maintenance and Repair, Remodeling, and Building Inspection, Kheli started the Handy Woman LLC to teach people how to take care of their homes. Along with typical home repair and maintenance services, her focus is to help our elders age-in-place and teach women homeowners how to understand and care for their homes. For more information please call Kheli at (303) 999-5812.