The types and brands of gypsum powder sold on the market are different, and the quality is also mixed. Therefore, the selection of appropriate, good gypsum powder to achieve the perfect effect of production.

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(lèi)石膏脆，但便宜。日常用于墻面的裝修，在建材市場(chǎng)能買(mǎi)到。

When choosing, might as well observe the color of gypsum powder. It is mainly divided into gray, yellow and white. Most of the gray gypsum powder is used for construction. After careful observation or immersion in water, we can find the small black particles in it. This kind of gypsum is brittle but cheap. Daily use for wall decoration, can be bought in the building materials market.

黃色的則為黃石膏粉。一般可以用來(lái)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 Huangshi powder. It can be used to make molds and sculptures. The fine yellow gypsum powder is hard, and the details meet the requirements of art production.

白色石膏粉是我們更為廣見(jiàn)的石膏材料，廣泛用于裝修、制模、雕塑等多類(lèi)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 the most widely seen gypsum material, widely used in decoration, mold making, 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(gòu)石膏時(shí)，包裝上的各類(lèi)數(shù)據(jù)可能使我們不知所擇，因此不妨來(lái)了解一下有關(guān)石膏的各類(lèi)數(shù)據(jù)。

When choosing gypsum, the various data on the package may make us do not know what to choose, so we may as well learn about the various data about 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, the details represent the fineness of gypsum powder. The details of extra hard white gypsum are usually 1100 mesh, and the construction gypsum is about 300 mesh. From this, 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: the compressive strength refers to the external force to crush and crack the gypsum. The 3-hour compressive strength of white gypsum for art is 8.1 MPa, and that for building gypsum is 4.9 MPa.

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　Ｃ佬g(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: the flexural strength represents the force per unit area that makes the material withstand bending moment fracture. The drying bending strength of gypsum for fine arts is about 10 ~ 12 MPa, while that for construction is about 8.4 MPa.

4，粘結(jié)強(qiáng)度：說(shuō)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(lèi)不同（分為粘結(jié)型和普通）因而其強(qiáng)度也會(huì)有所差異，建筑石膏也是如此，因而購(gòu)買(mǎi)時(shí)更好咨詢店家。

4. Bond strength: when it comes to bond strength, it may be easier to understand with an example - add water to flour and sand separately and mix them. The flour will stick together and the sand will disperse when touched. The bond strength of art gypsum is different due to different types (divided into bonding type and ordinary type), so the strength of construction gypsum is also different. Therefore, it is better to consult the store owner when purchasing.