Boil black plaster. The so-called drops of water turn into beads. What is the state of oil dripping into water before it turns into beads?

Oil refining is key. Pay attention to whether the oil is refined from the following three aspects. (1) Look at the oil smoke: after the oil boils, it will emit green smoke but the smoke is relatively light. When the green smoke changes from light to thick and turns gray, continue to boil, and then the smoke will turn white (the process takes about 1-2 minutes) and have the aroma of medicinal materials. At that time, oil refining was almost the same. (2) Look at the oil blooms: Generally, when the oil starts to boil, the oil blooms are around the wall of the pot, and the oil blooms start to gather in the center of the pot. (3) Drops of water form beads: A small amount of medicated oil is dropped into the water, and the oil droplets form beads and do not disperse. The above two methods 1 and 2 are relatively difficult to distinguish, so you can have a rough understanding. Let's talk about dripping water to form beads. This is a common method for making plasters in traditional methods. The oil refining process takes a long time, at least 30 minutes to an hour, or even longer. Prepare a basin of cold water in advance. You can simmer it for about half an hour. Remove the pot from the fire, dip a stirring stick into the medicated oil, and drop 1-2 drops into the basin. The medicated oil drips into the water. Gravity causes the oil droplets to disperse first. , then the oil droplets gather into beads and do not disperse, indicating that the oil is refining well. If the oil droplets spread out and do not condense, it means that the heat is not good enough and needs to be continued. Then try every 2-3 minutes. It may be troublesome the first time, but once you have done it a few times and become proficient, you will be able to do it mentally. The Laonen experiment is to test whether the plaster is finished.

Method

1. After the plaster is boiled and turned into a bright black plaster, remove from the fire first. You can take a drop of plaster and drop it on the plaster paper to check the adhesion of the plaster.

2. You can also put a little plaster into water. After cooling it slightly, you can pull out the thin threads with your hands to indicate that it is ready. If it is soft and weak, sticky to the hand, and unable to draw, it means it is too tender and needs to be cooked; if the thickness of the draw is uneven, or it is brittle, it means it has been overcooked.

3. Drop water to form beads: Drop a small amount of plaster into cold water. If beads do not fall apart and the plaster color is black and bright, it means it is ready. Gray means it's too tender and needs to be continued.

Too hard: usually the lead content is large and the cooking time is long.

Too soft: usually the amount of lead is small and the cooking time is short.

The above-mentioned methods 1 and 2 are commonly used to detect, and method 3 is enough to understand.