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为了加强理论联系实际,结合化学教材、贯彻勤工俭学方针,本期在高三讲完烧石膏后,解决学校粉笔自给。首先与附近手工业白铁小组的铜匠协作铸好两块铜模。用废铜熔铸,翻沙车光。如缺铜可用铝代替;亦可自己制造,先做好木模型。翻沙,向铜匠处买一个大的泥做坩埚,把废铝放进坩埚,在木炭或煤炉里熔融。铝熔点660℃,铜熔点1083℃。因此,用铜需用风箱拉风才能熔铸。再用钢打成六角棱的棒,如粉笔一样大小,下部小,上部稍大的条条。然后把铸好的两块模版钳紧,使转动棱棒滚削光滑即成。再用木材制造一个配有活叶(蝶铰子)能活动打开的木盒,用它套着模版,上面空缺,以备注石膏浆,木盒套着以防止石膏浆的漏失。
In order to strengthen the theory with practice, combined with chemistry textbooks, work-study program, this period in the third year finished burning plaster, to solve the school self-sufficiency in chalk. First, cast two copper molds in collaboration with the coppersmith of the nearby handicraft white iron group. Casting with scrap copper, turning the car light. Such as the lack of copper can be replaced by aluminum; can also create their own, the first good wood model. Flip the sand, buy a large mud to the coppersmith crucible, the scrap into the crucible, melting in a charcoal or coal stove. Aluminum melting point 660 ℃, the melting point of copper 1083 ℃. Therefore, the need to use copper bellows wind to cast. Re-steel bars into hexagonal ribs, the same size as the chalk, the lower part of the upper slightly larger section. Then cast the two pieces of a good template clamping, so that the rotating edge bar rolling smooth Serve. Then use wood to make a wooden box with living leaves (butterfly hinge) that can be opened. It is covered with a template with a vacancy in the note for gypsum slurry and wooden box to prevent the loss of gypsum slurry.