Backing
In addition to paper, backing for sandpaper includes cloth (cotton, polyester, rayon), PET film, and "fibre", or rubber. Cloth backing is used for sandpaper discs and belts, while mylar is used as backing for extremely fine grits. Fibre or vulcanized fibre is a strong backing material consisting of many layers of polymer impregnated paper. The weight of the backing is usually designated by a letter. For paper backings, the weight ratings range from "A" to "F," with A designating the lightest and F the heaviest. Letter nomenclature follows a different system for cloth backings, with the weight of the backing rated J, X, Y, T, and M, from lightest to heaviest. A flexible backing allows sandpaper to follow irregular contours of a workpiece; relatively inflexible backing is optimal for regular rounded or flat surfaces. Sandpaper backings may be glued to the paper or form a separate support structure for moving sandpaper, such as used in sanding belts and discs. Stronger paper or backing increases the ease of sanding wood. The harder the backing material, the faster the sanding, the faster the wear of the paper and the rougher the sanded surface.
Famous quotes containing the word backing:
“When I moved in with a bathing suit and tea bags
the ocean rumbled like a train backing up
and at each window secrets came in
like gas.”
—Anne Sexton (1928–1974)
“Better risk loss of truth than chance of error—that is your faith-vetoer’s exact position. He is actively playing his stake as much as the believer is; he is backing the field against the religious hypothesis, just as the believer is backing the religious hypothesis against the field.”
—William James (1842–1910)
“And no one, it seemed, had had the presence of mind
To initiate proceedings or stop the wheel
From the number it was backing away from as it stopped:
It was performing prettily; the puncture stayed unseen....”
—John Ashbery (b. 1927)