Re-striking Historic Plaques in Conservation
修复：历史铜牌的复冲与原貌保持
标签：铜牌修复, 复冲, 字迹复原, 最小干预
风化的建筑铜牌字迹变浅后，修复原则是优先清保护而非重冲；确需复冲时用硅胶翻制原牌取得凹版母模，浇注低熔点合金（Sn-Bi，熔点 138 ℃）做补偿冲头，冲压力取原工艺的 60–70% 并垫 2 mm 铅皮缓冲，避免压伤氧化层。某 1902 年门牌复冲后字口深度恢复 0.15 mm，原包浆仅边缘轻微扰动。全程记录冲压次数与压力，写入修复档案供后续追溯。
For weathered architectural plaques, conservation prefers stabilisation over re-striking. When re-striking is unavoidable, mould the original in silicone, cast a Sn-Bi compensation punch (mp 138 °C), strike at 60–70% of the original force over a 2 mm lead cushion to spare the patina. A 1902 door plaque regained 0.15 mm of letter depth with only slight edge disturbance; every blow and load is logged in the treatment record. ---