Selecting the Sandpaper

Technically, there is no longer an item called sandpaper. Today, these gritty sheets are called abrasive sheets, because they are made of abrasive materials other than sand. Five kinds of abrasives are used: flint, garnet, silicon carbide, aluminum oxide, and emery. The cheapest papers use Hint. They neither cut as fast nor

SANDPAPER

Manufacturers grade their abrasive papers by one of three methods, and there are no national standards to serve as a guide. Some give their papers a name (fine, medium, etc.); some rate them by grit number (30, 180, 400, etc.), referring to the abrasive particle size; and yet others use a numbering system (3/0, 5 0. 8 0), the oldest of all grading methods. The chart below shows all three methods in relation to each other, so that no matter which rating is used, you can buy the paper you need.

Number Grit Name When to use

600, 500

10/0

400

Superfine

Last sanding of a new furniture finish; final

9/0

360

sanding of fine woods; hand rubbed finish

80

320, 280

Extra fine

Same as above

7/0

240

6/0

200, 220

Very fine

Sand between coats of paint or varnish

5/0

180, 150

Fine

Sand hard and softwood before and after you

4/0

120, 100

stain, seal, or apply a priming coat

3/0

2/0

1

80, 60

Medium

Remove deep scratches in finish: remove rust.

0

50

Do shaping of parts or rough sanding

1/0

1/2

Vh

40, 36

Coarse

Wood removal, shaping, rough sanding, paint

2

30

removal

2 Vi

3

24, 20

Very

To remove multiple paint coats, fast wood

31/2

Coarse

removal

4

18

Extra

Remove heavy rust, paint, varnish

AVa

15

Coarse

New sandpaper is stiff, soften it to make il last longer by running it back and forth, face up, across a table edge.

last as long as the better papers. If you expect to do much sanding, it w ill pay you to buy better papers coated with one of the other abrasives.

Thickness Abrasive papers come in half a dozen thicknesses. The thinner papers are good for working in tight places because these weights fold easily. Ifowev-er, they are not as good for use in sanding blocks or on power sanders because the paper will tear. The heavier papers feel very stiff and may crack when folded, but they stand up longer in the power and hand sanders. You should have some of each weight.

Grains There are two kinds of papers, open grain and closed-grain. The open-grain type has only a light coating of abrasive material, made that way so that paint or other material being sanded doesn't

New sandpaper is stiff, soften it to make il last longer by running it back and forth, face up, across a table edge.

Make the block the shape needed for the work at hand Glue pieces of wood together if necessary The advantage of homemade blocks is their custom shape

When the cement dries lo the touch, carefully place the cemented sides together As soon as they touch, they bond permanently

Cut the sandpaper sheet so the piece is as wide as the sanding block and long enough to wrap around the block

Coat the wood block with contact cement: allow to dry Repeat on one side of the padding cling to the abrasive granules and clog the paper. This is the best for removing finishes. The closed-grain type has a dense coating of abrasive material and does its work more quickly. For general furniture smoothing and finishing, the closed-grain type is best. Buy some light-weight papers for sanding in and around corners, but buy mostly heavier papers for their longer mileage.

The Grit Numbers No one has ever actually standardized the method for indicating the coarseness of grit for abrasive papers. Sometimes you see papers marked with superfine, fine, medium and coarse. Other papers are marked in grit numbers ranging from 20 to 600, with 20 being the very coarse and 600 being the superfine. And still other papers use a grading system with numbers of 10/0 and 2/0.

To clarify the situation before you go to the store, check the accompanying chart, which shows the relationship between the different grading systems and tells the most common use for each type of abrasive paper. The grading method tells you nothing about paper thickness, type of abrasive, or general quality of the paper. It only specifies the size of the abrasive particles on the paper.

Waterproof Sandpaper In addition to standard abrasive papers, you can buy waterproof sandpaper. This is usually sold only in the finer grits and is made to be used with water or oil for the final rub-down in hand finishing.

Abrasive Cloths Abrasives glued to cloth last much longer than the paper versions, but are expensive and available only in a limited selection of grits. With one exception, we don't find abrasive cloths useful in furniture restoration.

The one exception is important. To sand rounded legs and rungs, and especially to sand into grooves on these rounded surfaces, you can cut strips of abrasive cloth to a convenient w idth, wrap the cloth around the leg or rung, and pull back and forth on the ends. This does a better job than regular abrasive papers. The narrow strip of abrasive cloth gets into the groove on a turned leg much more easily and successfully than the less flexible paper.

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