Step 6: Bake the Mold

Even though the plaster mold appears to be dry, there is moisture trapped in it. In order to dry it out and pre-heat it before melting the wax out use a conventional oven and very slowly increase the temperature. Heat shocking it will cause the mold to crack so be patient. Follow my next instructable on burning the wax out of the plaster mold for lost wax casting for further instruction. Have Fun!
<p>hello im really wondering, how do i actually make the wax, can i <br>actually make the wax? in this video it gave me the impression that i <br>could make it. <br>its should be time stamped so just click on it, but if not go to 5:17.</p><p>The man <br>says &quot;2 parts paraffin, and 1 part hot glue&quot;. So is it even possible to <br>make wax that wont completely meant to the hand and is good for casting?</p><p>I'm very new to this and am a bit lost. :P</p><p>https://youtu.be/avFjDDF5hks?t=5m17s</p>
You really didn't answer the question. I am also curious as to how do you make the wax. Or Failing, that where can we purchase it?
Crayons or cheap candles - just make sure they don't have chalk as a filler
<p>I'm assuming you mean the item that you want to eventually be made of metal. I had mine 3D printed at my local library, or you can find a plastic and carve or the like, as long as you can melt it out, then you should be good.</p>
<p>hey Gecko is my account^, i cant be bothered recovering the password, you didnt really answer the question.</p>
one ever gnawing doubt.. it is said that plaster of paris is a bad mould material if u r casting anything with a higher melting point than of lead.. and disaster for silver or copper.. suggestions? <br />
Good question! I have casted silver and aluminum in plaster molds with great results. There is a particular method of doing this though: You have to heat treat your molds. For investment molds a conventional oven works well. Over several hours gradually increase temperature to 400 then gradually decrease to cool as to not crack your mold with temp shock. With lost wax without a vacuum chamber you'll have to get it much hotter to burn out the wax. I use a kiln and ever so gradually increase the temperature to 1000 degrees. Then gradually bring down to cool and leave in the kiln over night. It always works despite varying opinions. Good Luck!
<p>wouldn't it make more sense to cast, high temp metals while they are hot? to reduce the high gradient shock, then reduce the temp gradually? in a kiln with a programmable controller, designed for annealing glass. </p>
<p>You may not want the metals to cool down gradually, I don't know how aluminum or brass would react, but it could be a factor.</p>
hey!! thanks for the tips! <br>will let u know next time i cast!
<p>Is it just plaster of paris, and not a mixture of something else with the plaster? I'm going to be casting with aluminum, which is about 1100 degrees when liquid, so will the plaster take that heat?</p>
<p>It should, if you cure it properly. You may still crack the mold, but if it has supports (such as the container you made the mold in) you should still get a good cast.</p>
Lost casting statue
Nice one! Check my instructable on making a vibration box to get the bubbles out! Thanks
<p>I know this is two years late. Great Instructable. I have cast bronze and aluminum in a plaster lost wax mold. It's how I originally learned. I've done it for small (jewelry scale) sculptures and larger scale sculptures. The largest size is 18&quot;X18&quot;.</p>
Very informative! I just wish it was longer.
Wow. Thank you for this write up. I've been looking into doing this for some time (been using lost foam casting) and now this weekend I will try my hand in lost wax casting. Thank you again.

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