If you are new to CNC turning, you know that the learning curve is steep: It takes a lot of practice to figure out how to properly machine pieces like those found when you visit http://www.cam-machine.com/cnc-turning/, so that they are the right shape and size and have an excellent finish. Along the way, most budding machinists waste a lot of material and sometimes damage their machine’s cutting tools as well—all of which adds up.
Fortunately, there is a better way; “machinable wax” offers machinists the opportunity to experiment with CNC turning without wasting costly materials and without putting any real wear on their machines (as wax is easy to cut). Once a piece of wax has been cut, it can simply be melted down again and shaped back into a block, allowing the machinist to create multiple projects from a single piece of material.
Making Machinable Wax At Home
Machinists who are looking for the most economical option possible often choose to create their own machinable wax at home rather than ordering a block online. If you choose to do this, it is absolutely essential to put safety first; working with hot wax can cause severe burns and the materials involved can catch fire if overheated. If you lack proper safety equipment or you don’t feel confident in your ability to make machinable wax, it’s better to simply purchase it.
With the above disclaimer in mind, if you choose to max machinable wax at home, you will need:
-Safety goggles;
-Leather fire-resistant safety gloves;
-A fire extinguisher;
-A candy thermometer to monitor the temperature of the wax;
-Paraffin wax;
-An inexpensive deep fryer with an adjustable thermostat;
-Plastic shopping bags (HDPE or LDPE), cut into strips;
-A wooden spoon;
-Molds (with a flat bottom);
-A strainer (one you don’t plan to reuse);
-Wax paper and a scale can also be useful.
In the deep fryer, heat the wax until it reaches about 148 degrees Celsius (300 degrees Fahrenheit), stirring frequently to keep the temperature of the wax even (“hot spots” in the wax could cause a fire). Once the required temperature has been achieved, add the strips of plastic bag; make sure to keep stirring the mixture as you add the bags, but don’t stir too quickly as overzealous stirring may add air bubbles to the wax. Once the bags have dissolved thoroughly, run the mixture through a strainer to remove any remaining lumps of plastic. You should then be ready to pour the hot liquid into your molds.
Once you have poured the liquid into the molds, cover the molds with paper towels so that the mixture cools slowly—this will help to ensure that any air bubbles within it have time to escape. (Be aware that when you release the wax from the mold, you may need to do some finishing work on it to create perfectly even blocks.)
As a final note, when you go to recycle your block of wax after a CNC turning operation, make sure to blend it 50/50 with new materials (melt the new material first, before adding old wax). Because plastics degrade quickly, simply melting down used wax without any new material added can create issues with smoking, burning, and possible ignition.
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