| 摘要 |
The ladder rung top surface is sweep-blasted with fine particles, pref. fine sand grains hardenable pulp is then applied to it, contg. glass-reinforced polyester, to constitute a complete coating, application being by spraying or rolling. Before the coating hardens, grains of fine sand grains are applied to it. These grains sink downwards into the coating, and are fixed when it hardens. |
