Sanding tutorial ( for those that want to know more)
A sanded surface is nothing more than progressively finer and more numerous scratches. Therefore, skipping a grit leaves deep valleys that successive grits are hard-pressed to remove.
A general rule for the use of sandpaper is as follows-the finer the sandpaper used, the lighter the stain color will be. Conversely, the coarser the sandpaper used the darker the stain color will be. Remember that a coarser sanding job will look less refined than the smoother surface that comes from progressing through increasingly finer grits of sandpaper. Final sanding will bring the surface to the desired smoothness. Sanding must be thorough, even and with the grain of the wood. If these criteria are met, no further sanding will be necessary. Since there are so many grades of sandpaper available, some knowledge of what the various designations mean and a little practice are useful in order to take advantage of this important tool. This chart is based on our experience and is intended as a guideline only.
|
| Very Fine |
600 |
10/0 |
Polishing and finishing after staining |
| 400 |
0/9 |
| 360 |
8/0 |
| 320 |
7/0 |
| 280 |
|
| 240 |
|
Fine
Medium Fine |
|
6/0 |
Finish sanding before staining |
| 220 |
5/0 |
| 180 |
4/0 |
| 150 |
3/0 |
| 120 |
|
| Medium |
100 |
2/0 |
Removing rough texture |
| 70 |
1/0 |
| 60 |
1/2 |
| Coarse |
50 |
1 |
Distressing, rounding and rough areas |
|
40 |
1 |
|
36 |
1.5 |
Very
Coarse |
30 |
2.5 |
Very rough unfinished wood
|
| 24 |
3 |
| 20 |
3.5 |
| 16 |
4 |
The number of identification or grit number on the back of sandpaper sheets indicates the smallest opening through which the abrasive particles will pass. For sandpaper marked 220 the abrasive particles will pass through a screen with 220 openings per linear inch.
The designation 'Open Coat' indicates a particle distribution to prevent the paper from
clogging. The adhesive used on wet or dry sandpaper is resistant to water, oils and paint
thinner.
- The adhesive used on standard sandpaper is water sensitive.
- Cabinet grade sandpaper is backed with heavy paper.
- Finishing grade is backed with more pliable paper.
The types of abrasives commonly used for furniture finishing are garnet, aluminum oxide and
silicon carbide. In general, red garnet paper is used primarily for hand sanding. Grey to
white aluminum oxide is used for either hand or power sanding; black silicon carbide is the
abrasive of choice for very fine sanding in the woodworking field.
|
| Oak |
120 |
150 |
180 |
| Birch |
120 |
150 |
180 |
| Maple |
120 |
120 |
180 |
| Mahogany |
150 |
180 |
220 |
| Walnut |
150 |
180 |
220 |
| Fir |
120 |
150 |
180 |
| Pine |
120 |
150 |
120 |
| Cherry |
120 |
150 |
220 |
| White Ash |
102 |
150 |
180 |
Coarse sandpapers below 100 grit, are rarely used for fine furniture finishing. They may, on occasion, be useful for distressing the surface, rounding harsh corners, or breaking down extremely rough areas. The grades of sandpaper used most for furniture finishing fall in the fine and very fine categories-that is from 120 grit through 220 grit; with 320, 400 and 600 grit used for special purposes. For "hard to stain" woods, finish sanding with 120 grit will usually accommodate the problem. For finish sanding on most furniture hardwoods (e.g., cherry and mahogany) use 180 grit or 220 grit. The use of grits up to 600 is certainly allowed but is not standard practice. Usually you will have to make a concession either to surface smoothness or to color acceptance. Factory sanded furniture still requires finish sanding. Do the initial sanding with medium fine paper and finish with one or more of the finer grades. Be sure you sand the whole surface with the same grit paper. Do not miss a spot. If you do, the stain will be darker on the rougher areas. |
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