铜大缸采用树脂砂铸造，工艺好，不走形，采用62#焊条，气焊焊接跟整体铸造效果一样，还有这种焊条不与纯铜产生氧化，不会反绿锈。这就是62#焊条的价值所在。铜大缸再焊接、打磨，完成后，进行表面处理，做颜色，着色化学药腐蚀。用火枪烤到一定的温度用喷壶喷在上面，让药水吃到铜里面这样用不掉色，色泽永远都是就像刚做的一样。保留的时间上，{可以达到100年都没问题}因为药水能吃到铜里面0.5mm。

Copper cylinder is cast with resin sand, which has good technology and no deformity. 62 # welding rod is used. Gas welding has the same effect as whole casting. Moreover, this kind of welding rod does not oxidize with pure copper and will not reverse green rust. This is the value of 62 # electrode. Copper cylinder is re-welded and polished. After finishing, surface treatment is carried out to make color and stain chemical corrosion. Use a gun to roast to a certain temperature and spray it on it with a spray pot, so that the potion can be eaten into the copper so as not to fade, and the color will always be just like that. In terms of retention time, {can reach 100 years is no problem} because the potion can eat copper 0.5mm.