The screed should be uniform, and the symmetrical distribution of the hot glass in each part mainly depends on whether the rotation speed of the blown iron pipe is proper, and the rotation speed is too fast or too slow, which will cause partial unevenness of the product;

The blowing time and the blowing amount should be just right. If the blowing is too large, the product will be too thin and the size will be too large; on the contrary, the end will be too thick and the size will be small. Therefore, luck is at ease, and the blowing power is just right to ensure the size of the product.

The weight of the picking should be basically the same every time, because this molding method mainly relies on the feel and experience. The viscosity of the upper glass liquid is different from the viscosity of the glass near the bottom of the crucible. Pay special attention when picking up the material.

Manual blow molding is labor-intensive and difficult, but it can be used for thousands of years without deterioration. It is mainly flexible and artistic, and it is still an important molding method in the glass industry.