The purpose was to continue to illustrate a little fellow from a few years back that I do believe has some merit. I've done a multitude of simple thumbnails and wips on the guy, but somehow creating a posing figure that represented more of the proportions from that character seemed not only helpful but let's face it - fun!
Once the basic figure was formed and cleaned, I had attempted a first trial - with some unfortunate results. Using some household products: silicone, corn starch and low odor mineral spirits, I had attempted a mixture. The silicone product however, contained other materials which reacted not only with the mineral spirits, but the oil based clay beneath. Long story short...it was a mess and one that luckily was able to be rectified with q-tips and toilet paper to clean off.
Second trial started with using 100% silicone mixed with the mineral spirits worked with much greater effectiveness. When researching on the net, there are many others who have used this methodology and the same three products with varying results.
I found that a 4:3 ratio of mineral spirits to silicone, blended well, gave a great runny consistency. To this, I added 2 heaping teaspoons of corn starch as the thickening agent. It yield a pot life of approximately 7-10 minutes to work with the substance. It should be noted that higher amounts of mineral spirits to the pure silicone will increase the liquid nature, as will the lower proportions of corn starch. Drying times also reportedly vary, this trial took about 25 minutes to the touch, and an extra hour cure time before putting on a second coat.
Three coats later and I had a pretty thick flexible mold. Next was to create the mother mold of plaster that would encompass the silicone mold to add some stability for future pours. I started with a simple box:
Tape was used to help provide a little more rigidity from liquid coming from the plaster later on, and also to help keep the sand that will be used in the first half of the pour.
The silicone mold was placed in the box with sand covering the lower half of the mold. The sprue was placed firmly against the side of the box.
The first side poured. Next comes removing the sand from the bottom and then pour the second half of the mother mold.
The second pour of plaster. The bottom of the box was cut open slightly to release the sand into a bucket, and then a soft paintbrush was used to brush off the vast majority of sand on the bottom side. Then, once release from the mold, the piece was flipped and re-positioned so once again the sprue was flush with a side; and finally the second side was poured/smeared on top.
And here we have the end result: two halves to the whole mold. I am excited about the first resin pour. All there is now to do is clean out the clay residue and get things prepped for pouring!
UPDATE: 12/28/2012:
Ok, trying not to slam my head against the wall for such a stupid rookie move F@#$-Up I did on the first resin pour.
See the marvelous shaft/tube like area between the legs? A support during sculpting, and removed when the plaster mother mold was created. And right as I was pouring the resin...and watching it come out into the sand-lined tray below the mold...remembered that that lovely HUGE escape tunnel had not been plugged up prior to pouring. ARRRRRGH!
On the bright side, several things: The Alumilite 2-part resin needed no release agent from the silicon mold (very lucky mistake on that one..forgot a release agent as well); clean up went quick for the silicon; and once the tube chamber filled up, the hands, feet, legs and lower torso formed. So at least I have some spares when it comes to making the figure for posing.
UPDATE 1/9/2013:
Second pour today resulting in an almost complete figure. This time around, that hole was plugged up and although there seemed to be a small amount leaking, all went pretty well. Well, that is until the resin hit the flash point about five seconds earlier than I needed. The result was a great pour for feet, legs, torso, neck and head..but no arms. Third time will be a charm!
There was one minor keying issue around one side of the head; and since I have enough to keep the form filled, I will be slightly bulking up the silicone portion a tad bit more and then reforming the plaster mother mold pieces.
