Waxmaking & Casting

 

This video shows a few scenes of brown wax being made and then being molded into a blank cylinder.
 
 
 
 
 
The wax batch #84 was made Friday, 8/16/13. The first blank cylinder M255 shown being cast from batch #84 was made Saturday, 8/17/13.
 
The reaming and shaving and test recordings were done on M255 the following Monday, 8/19/13.
 
This video runs for only 5 minutes and shows only a few of the highlights.
 
The clear liquid is hydrated aluminum, which is made with distilled water, sodium hydroxide (lye), and a small amount of pure aluminum metal. This solution is filtered until water-clear, then added to the melted stearic acid in small amounts throughout the cooking. There are (16) such "portionwise" additions. The whole wax batch takes about 2.5 hours to complete.
 
At the beginning, the temperature is 190 C. After the first (6) additions of hydrated aluminum, the temperature slowly rises for following additions, as the reaction itself becomes exothermic, throwing off its own heat, and adding to what the stove fire puts in.
 
Finally, toward the end of the reaction, the temperature rises to 270 C, which is 518 degrees F. 
 
In this final stage during the high-temperature end of the process, the increased solubility of the saponified stearic is taken advantage of at this high temperature in order to assure complete combining of the crusty precipitate that you can see in the video.
 
This temperature is well over the flashpoint, and if made in a shallow container, it will catch on fire. The tall pot prevents this.
 
Then, once everything is thoroughly combined, the last 25% of fresh stearic is added, cooked in a bit at 250 C, then the temperature is lowered to 232 C (which is 450 F), for the remainder of the cooking, which then later also involves the addition of a small percentage of ceresin wax that tempers the mix and also makes the final brown wax non-hygroscopic. (it does not absorb water).
 
The casting process takes just under 3 hours from the time the mold goes into the preheating oven, until the casting comes out.
 
I hope that this rather lengthy explanation adds a bit to the short video.
 
Chuck
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