Intro: Lost Wax Casting
My wife wanted a china cabinet, but no ordinary china cabinet. She wanted one to make her friends jealous, so I decided to make the handles myself by using lost wax casting. I had never done this before, so I read a few articles on the internet. I started to accumulate the needed things, and this is what I got.
WARNING THIS CAN BE DANGEROUS, TRY AT YOUR OWN RISK
Wax- I used injection wax it can be bought from EBAY. Also you can use other types of wax, it needs to be hard wax though.
Plaster of Pairs- It can be bought pretty much anywhere, and believe it or not it can handle substantial heat.
Silicone Mold- This will be what you make the main part of your casting from.
Heat resistant measuring cup- this will be used for melting the wax, the spout on the measuring cup makes it pour easier.
Wood- size will depend on how long you want the stud on the back of the handle to be.
Tap- this is what I used to cut the threads into the stud of the handle
A few other items that I will detail in the instructable
The first step is to decide what you want to cast, I chose to make handles for a china cabinet that I had made my wife. I bought the letter m mold off of eBay, you can always carve the wax but I wanted to make multiple molds in a short period of time. I also bought injection wax off of the internet, it holds heat well and cools very hard. I took my heat resistant glass measuring cup (Pyrex) and melted my wax in the microwave, melting times will vary by microwave. Be careful if you get the cup to hot it will crack or start to melt itself ( both of these happened to me). After you melt your wax pour it into your mold, it will take around thirty minutes to cool. I used this time to make the stud for the back of my mold. I drilled a 3/8" hole in a 1x4 with a forstner bit, i used the forstner bit so the sides of the hole will be smooth. I then screwed another 1x4 to it to make a back to stop the wax, then poured wax into the hole. I actually made about 24 studs at a time. You will need extra studs to leave vent holes for escaping gas. After all the wax cools and hardens you take the stud and letter m and marry the two with hot wax. ( I used pam on all molds to help the wax come out.)
The next step is to put the wax into the plaster of paris, you mix up the plaster according to the directions and pour into a container. I used Styrofoam cups for this, it made it easier to get the plaster out. After mixing up the plaster gently place the wax mold letter down leaving the studs at the surface of the plaster. The next step is to fire the plaster, this serves two purposes to melt the was out leaving a negative void for the hot metal to go. Also it tempers the plaster, taking all the moisture out of it and making it harder. ( this step is important, if you don't do it the plaster may explode). I used an old cookie sheet and my bbq grill, you turn the molds upside down and turn the grill up 3/4 of the way for about thirty minutes. Make sure to keep an eye on it so that nothing burns up. Now your ready for the metal.
The next step is to melt the metal, I used copper to make mine. Copper oxidizes very badly so make sure to use some borax and a graphite stir rod to mix with the copper as it melts ( purchased of eBay). I used a graphite pot and a cutting torch with a rose bud tip, you can also use a melting furnace if you know someone with one or if you have one. You melt the copper to a boiling liquid ( around 2000 degrees F'), use a set of tongs or what ever you can find to hold the pot and pour into the mold. Make sure to wear safety gear, heat resistant gloves and shirt. Safety glasses etc.
After the metal cools you bust the molds with a hammer and your left with a copper handle. The next step is to clean it up, you grind the extra studs on the back off. Even out the middle stud, I used a bench grinder. Next step is to drill out the stud with a tap set, I used a #8 size tap set. After drilling the hole in the center of the stud I used the tap and cut the threads into the stud. Lastly I polished it up with a wire wheel, to get the copper shined up really nice.
Leave comments and questions.