Thursday, June 21, 2012

Pouring waxes "the good, the bad and the ugly"

Preparing Mold



 I have talked about pouring wax before but maybe not quite as in depth.  This first picture is of me putting my molds together in a really simple two piece mold which I have already sprayed with release and in my own creative method taped the sides together with reliable old grey tape.

You can not tell but I already have had my cookers on for several hours, which is what it takes to melt all my wax down to where there are no clumps or chunks on the bottom and as they are melting down I clean all my spoons and dipping pans. Make sure your dipping pan has a pour dent.

You actually have to start the roasters out at around 400 degrees to get it to all melt then you begin backing it off to the temperature you desire, one tub is 200 degrees and the other is anywhere from 180 to 160 depending on what I am pouring. I have thermometers in each roaster (which you can see in the second picture) showing me the constant temperature.

 Some molds are actually small enough that you can do them the way I am doing but then other times they are too large and you need two people one to pour and the other to support and roll the mold. Also notice that I have a heavy apron on the protect me from splatters of hot wax and a bowl of water in between the roasters just in case I have to dip my hand in to cool or peel off the hot wax.

actually pouring into small mold
Look at the figure I am holding in the third picture and imagine it covered in plaster where you can not see the shape, you have to know where the nose is and where the tail is and just how much to tip the mold to get the hot wax to run into the ends.

 You have to pour the first 200 degree wax into the mold and fill it all the way to the top,  shake it a tiny bit to get the hot wax to go into feet and tiny details (horns if applies) and especially rotate it towards things like noses or tails. Then as you start to rotate your mold and tip it to empty the hot wax you make sure you are covering every square 1/2 inch of pour spout to show you that you have evenly distributed the hot wax all the way around as you rotate and tip to pour it out.

I usually pour two of the 200 degree and then two of the 170 or so temperature making sure to get the complete rotation of the work to where the thickness is the same all the way around.

The most important is of course the 200 because it is picking up the tiny details and if poured too fast it will be the one to create bubbles or if you pour too slow it will show the ripple affect on the side of our wax when you pop it out of the mold.  You want your wax around the 1/8th of an inch thick all around the work.

There will be cases where you will have a tiny piece and only pour one pour and it will be solid.  I make all my horns (because I work desktop and small) solid where they will handle the sprueing and preparation of the crust mold that is produced before casting.

Where I have found problems is when I have created something for instance an animals curled up that creates a cavity in the center then that will be a hill or high point in your mold (you are looking at the inside). You will actually at the end of pouring the four times have to cool your wax even further and spoon a little at a time to cover the "protruding areas" or high spots or you will have a hole there.


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