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Expert's Corner — lead

TIP: Testing Your Finish for Hardness

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TIP: Testing Your Finish for Hardness

You can use architect’s pencils to test for finish hardness (scratch resistance). The lead in these pencils is rated from about 6 or 7B, the softest, to 6 or 7H, the hardest. HB is in the middle. You don’t need to buy all these pencils, just the middle five or six, because most finishes will test to one of these. To prepare the pencils sharpen them with a pocketknife, not a pencil sharpener. Then ground the tip of the lead perpendicular to the length of the pencil on fine sandpaper, or regular paper if the lead is close to flat....

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