Wax tree planting

After the wax molds are trimmed, wax trees need to be planted before further operations can be carried out.

Planting wax trees is to weld the wax molds made in a certain order to a wax stick layer by layer along the circumference with a wax welder, to finally get a wax tree that looks like a big tree, and then pour the wax tree into gypsum and other processes. The basic requirement of planting wax trees is that the wax molds should be arranged in order, and the key is that the wax molds cannot be contacted, which can not only maintain a certain gap, but also weld as many wax molds on the wax trees as possible, that is, the largest number of wax molds should be "planted" on a wax tree, which has met the needs of mass production.

Wax trees must be planted on a round rubber chassis. The diameter of the rubber chassis is matched with the inner diameter of the stainless steel cylinder. Generally, the diameter of rubber chassis is 3 inches, 3.5 inches, and 4 inches. There is a protruding circular concave hole in the center of the chassis, and the diameter of the concave hole is equivalent to the diameter of the wax stick of the wax tree. The first step of "planting wax trees" is to dip the head of the wax stick with some molten wax, and insert it into the concave hole of the chassis while it is hot, so that the wax stick can be firmly combined with the concave hole.

The second step is to weld the wax mold on the wax stick layer by layer, which can start from the bottom of the wax stick (from bottom to top) or the head of the wax stick (from top to bottom). If the technology of "planting trees" is relatively skilled, the difference between the two methods is not great; however, generally, many methods are starting from the head of the wax stick (from top to bottom), because the biggest advantage of this method is that it can prevent the molten wax from dripping onto the welded wax mold, and avoid unnecessary rework caused by the wax dripping.

The following problems should be paid attention to in the operation process of planting wax trees.

1. There is usually an included angle of 45 ° between the wax mold water channel and the wax stick for planting wax trees, that is, the direction of the wax mold is inclined upward. Only in this way can golden water be smoothly injected into the plaster mold. The included angle can be adjusted appropriately according to the size and complexity of the wax model, and small and complex wax models can reduce the included angle; On the contrary, a larger wax model can increase the included angle.

2. Before planting wax trees, the rubber chassis should be weighed first. After planting wax trees, weigh again. The weight of the wax tree can be obtained by subtracting the results of the two weights. By converting the weight of the wax tree into the weight of metal according to the density ratio of paraffin and cast metal, we can estimate how much metal is needed for casting.

3. After planting wax trees, you must check whether the wax molds have been welded firmly. If it is not welded firmly, it is easy to cause the wax mold to fall off when pouring gypsum, affecting the casting process. Finally, we should check whether there is enough gap between the wax molds. If the wax molds are pasted together, they should be separated; If there are wax drops on the wax tree, it should be repaired with a blade.

Plaster pouring and vacuum pumping

Put the wax tree with the chassis on a stainless steel cylinder (steel bell), and wrap one-sided adhesive tape on the outside of the steel bell (the adhesive tape should be about 20cm higher than the top edge of the steel bell at last) for standby.

1. Mixing gypsum slurry: prepare gypsum powder and water of corresponding weight according to the specific volume of the steel bell (if there is no distilled water, tap water can also be used). Generally, the ratio of gypsum powder and water is 2~2.5:1 (at this time, the proportion of gypsum slurry is about 2). It can be adjusted according to the dry and wet climate, cold and warm, as well as the size and complexity of the mold. The water temperature is relatively appropriate between 20~25 ℃. First, put the water into the mixing container, start the mixer, gradually add gypsum powder, stir for about 10 minutes, and then vacuum for the first time (1-2 minutes).

2. Plaster pouring: the gypsum slurry after vacuum pumping shall be injected slowly along the inner wall of the steel bell immediately. It is forbidden to pour the gypsum slurry directly on the wax tree until the gypsum slurry is about 1cm below the wax tree, and the second vacuum pumping shall be carried out immediately. After vacuum pumping for 2 minutes, place it naturally for 6~12 hours to ensure the solidification of gypsum.

Baked gypsum

The baking of gypsum mold is an important process to ensure normal casting. Generally speaking, the mold baking time of 18K gold is 6-12 hours, and that of platinum is 12-20 hours. The main functions of baking are dewaxing, dr,ying, and casting insulation. Take the baking of 18 K gold as an example, the dewaxing temperature is 0~350 ℃, and the holding time is 2 hours; The drying temperature is 350~700 ℃, and the holding time is 2~3 hours; The casting insulation temperature is 600~500 ℃, and the insulation time is 1~2 hours.

The general baking process is: first, preheat the resistance furnace to the initial temperature, and put the gypsum mold nozzle down into the furnace so that the wax liquid flows out and evaporates; After maintaining a constant temperature in the initial temperature zone for 1 hour, gradually increase/decrease temperature and maintain a constant temperature at an interval of 1~2 hours. Note that the heating (or cooling) rate should be maintained at 100~200 ℃ / hour, otherwise too fast heating is likely to form cracks in the gypsum mold, which may seriously cause damage or scrap of the gypsum mold, and too slow heating is likely to cause wax residue or incomplete drying of the gypsum mold, which will affect the quality of the casting. The baking time of gypsum mold mainly depends on the size and complexity of the gold tree, which can be adjusted according to the specific situation.

Searching for a lost wax bronze sculpture, lost wax casting price, lost wax casting ceramic slurry supplier, wholesaler, manufacturer from China, you can get high-quality products at a nice price.