The types and brands of gypsum powder sold on the market are different, and the quality of gypsum powder varies from good to bad. So choosing suitable and good gypsum powder can achieve the most perfect effect.

　　在選用的時(shí)候，不妨觀察石膏粉的顏色。主要分為灰色，黃色，白色。灰色的石膏粉大都為建筑用石膏，仔細(xì)觀察或浸水后便能發(fā)現(xiàn)其中的黑色小顆粒雜質(zhì)。該類石膏脆，但便宜。日常用于墻面的裝修，在建材市場能買到。

　　When choosing gypsum powder, you might as well observe the color of gypsum powder. It is mainly divided into gray, yellow and white. Grey gypsum powder is mostly used for building gypsum. After careful observation or immersion, small black impurities can be found. This kind of gypsum is crisp but cheap. Daily wall decoration, in the building materials market can be bought.

　　黃色的則為黃石膏粉。一般可以用來制模，雕塑。好的黃色石膏粉堅(jiān)硬，細(xì)目也很符合美術(shù)制作的要求。

　　The yellow one is yellow gypsum powder. Usually it can be used to make moulds and sculptures. Good yellow gypsum powder is hard and detailed, which also meets the requirements of art production.

　　白色石膏粉是我們?yōu)閺V見的石膏材料，廣泛用于裝修、制模、雕塑等多類領(lǐng)域。好的白色石膏粉細(xì)目高，硬度好。有的還添加了少許碳酸鈣，達(dá)到了極為堅(jiān)硬的效果。

　　White gypsum powder is our most common gypsum material, widely used in decoration, moulding, sculpture and other fields. Good white gypsum powder has high fineness and good hardness. Some also added a little calcium carbonate, to achieve a very hard effect.

　　選購石膏時(shí)，包裝上的各類數(shù)據(jù)可能使我們不知所擇，因此不妨來了解一下有關(guān)石膏的各類數(shù)據(jù)。

　　When choosing gypsum, we may not know what to choose from the various data on the package, so we might as well learn about the various data on gypsum.

　　1，細(xì)目（細(xì)度）：顧名思義，細(xì)目代表著石膏粉的細(xì)膩程度，特硬白石膏的細(xì)目通常為1100目上下，建筑用石膏的細(xì)目約在300目左右，由此我們便能看出許多差距。

　　1. Details (fineness): As the name implies, details represent the fineness of gypsum powder. The details of extra-hard white gypsum are usually about 1100 meshes. The details of building gypsum are about 300 meshes, so we can see many gaps.

　　2，抗壓強(qiáng)度：抗壓強(qiáng)度指的是外界把石膏壓碎裂的力的大小，美術(shù)用白石膏的3小時(shí)抗壓強(qiáng)度為8.1毫帕，建筑用石膏的3小時(shí)抗壓強(qiáng)度約為4.9毫帕。

　　2. Compressive strength: Compressive strength refers to the external crushing force of gypsum. The three-hour compressive strength of white gypsum for art is 8.1 millipa, and that of gypsum for construction is about 4.9 millipa.

　　3，抗折強(qiáng)度：抗折強(qiáng)度代表單位面積使材料承受彎矩?cái)嗔训牧Φ拇笮?。美術(shù)用石膏的烘干抗折強(qiáng)度約為10~12毫帕，建筑用石膏則為8.4毫帕左右。

　　3. Flexural strength: Flexural strength represents the amount of force per unit area that causes the material to withstand moment fracture. The drying flexural strength of gypsum for art is about 10-12 MPa, while that of gypsum for construction is about 8.4 MPa.

　　4，粘結(jié)強(qiáng)度：說道粘結(jié)強(qiáng)度，舉一個(gè)例子或許能更易理解——分別向面粉與沙子中加水并攪拌，面粉能粘成一團(tuán)，而沙子一觸即散。美術(shù)石膏的粘結(jié)強(qiáng)度因種類不同（分為粘結(jié)型和普通）因而其強(qiáng)度也會有所差異，建筑石膏也是如此，因而購買時(shí)好咨詢店家。

　　4. Bond Strength: When it comes to bond strength, it may be easier to understand, for example, by adding water to flour and sand and stirring them separately, the flour will stick together and the sand will disperse when touched. The bond strength of artistic gypsum varies according to its type (divided into bond type and common), so does the strength of architectural gypsum, so it is best to consult the shop when purchasing.