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Which brings us to this picture. Why, you may reasonably ask, is there a jawset model in my freezer? Very simply, freezing the clay helps keep squishing to a minimum, so I can check the teeth and gums for fit and do as little damage as possible. This kind of plasticine, Monster Clay, contains a high amount of wax, so it freezes very well. 






Pictured here are another secret weapon in my arsenal, rubber tipped shaping tools. These also helped keep squishing to a minimum, as they made it possible to apply just the tiniest, most precise amount of pressure to only the areas it was needed. Unlike big fat fingers.


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Right, rubber poured over the models. Coloring it like this helps to show when the two parts of the rubber are fully mixed, so that it can be stirred only as much as necessary, avoiding excess bubbles. Pouring the rubber into the molds from relatively high up, in a thin, slow stream, also helps to break bubbles that have formed while stirring. Brushing a thin coat of rubber over the model, letting it partly set, and then pouring the rest of the rubber in also helps, as bubbles trapped against the model can more easily rise to the surface and break that way.

And, resin gums poured into the two new molds.

​Teeth waiting for rubber in their own Lego mold box...

​And rubber poured. Another thing that helps eliminate bubbles is tapping the mold box on the work table after the rubber is poured, to help the bubbles rise up to the surface and break.









 (I found myself often thinking of this scene from Finding Nemo during this whole thing...)

​Resin gums cast into one mold, teeth into the other...

​And, teeth and gums removed from the molds, and... THEY FIT TOGETHER!!! YAAAAAYYYYY!!!!

I don't remember what inspired me to make the upper half of a jawset out of blue silicone rubber, nor what inspired me to use it as a window cling in the dining room. However seeing it hanging there gave me a new idea to try for a two part mold. So here goes!

​Here goes nothing! The white resin is poured into the mold. (The mold on the left hand side is for claws.)

​The blue mold piece is removed, leaving the white teeth in the translucent mold piece.

Pouring the pink resin into the mold. It overflowed a little to one side, not a big deal as it can be trimmed off after it sets up.

So I was unenamoured with airbrushing, at least when it came to painting jawsets, and I decided to attempt to cast them in two different colors of resin. The saints at the Smooth On tech support department recommended I pour one color of resin over the other before it had a chance to set up fully.To the left, the result. Um, no.

Removing the cured rubber from the mold, with the teeth still attached. It would appear I have my model from which to make a mold for the gums. (The fabric was added while the rubber was curing, so that I'd have something to glue the models down to the mold board with afterwards. It wouldn't work so well to just glue the silicone to the mold board, as cured silicone doesn't stick to much of anything.)

Here goes nothing! Pouring the silicone over the models for the new gum mold. (The snaky thing on the far right is an attempt at a lip.)

First, I made "plates" for both the upper and lower jaw, making sure they fit comfortably inside the resin head. Then, using Skully and reference pictures I found online, I sketched the placement of the teeth on the "plates". Using a lightbox, I then checked to see how the teeth on the upper and lower jaw would line up with each other (left). These would serve as "templates" for the jawset.

Now it's time to start sculpting! Left, rechecking the template in the lower jaw.





























​Gum line built up (and though it's hard to see) tooth placement traced in from the template.  

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​Actual teeth taking shape. The whole thing is built on a thick piece of cardboard, so I can take it in and out of the mask's mouth without squishing it. Not too badly, anyway.

​Now for the upper jaw. Left, checking the template for the upper teeth inside the resin head, using Skully and photos for reference.

​Gumline built up, roof of mouth roughed out, and tooth placement traced in, using the template. 

​And, roof of the mouth more refined, and actual teeth taking shape.

Left, making molds! I've used cheap Tupperware type containers for the mold boxes, attaching them to the mold boards with hot glue and cutting openings out of the bottoms for pouring in the rubber. 

​And, casting resin into the new molds to make teeth! Wheee!!! 

 

Last but not least, a freshly textured nose and tongue, ready for moldmaking.

The rubber curing and then  being removed from the Lego mold boxes. I sealed all the little gaps between the bricks with Sonite Wax **except** the one between the first row and the mold board, with the results seen below on the left. Brain cramp!! Little rubber Lego bricks! Fortunately the hot glue attaching the Lego mold  box to the mold board kept the leak from getting out of hand, the worst effect being I didn't have quite the thickness of rubber I would have liked around the model at the top of the mold. 

​In the home stretch! Right, casting a nose and some teeth in the new molds.

 Joanie: There are a few things that might help you in your journey. The first thing that caught my attention is your mold keys. They look like they are good in theory, but not in practice. The mold keys need to be made along with your rubber mold piece, not attached to it afterward. In plaster mold making, you want your keys to be round (not squared off) and tapered, but in rubber you can be less finicky. Build the keys in as you paint on the rubber. You can glue them on between layers, then paint more over them maybe.  

Me: So it sounds like another approach I could use is to have the rubber snakies ready to go, but paint them in to the last coat of rubber as I'm applying it, not glue them on afterwards?

Joanie: That would work better. Depending on layer thickness, one or two layers need to be applied over the top.

Think I would consider one long ridge down the rubber where the plaster goes. Like a short separating wall. Then painted with rubber. Would make a fine key. The wormies could be made of clay. Or whatever. Or just build up as you paint. 
 
Me: What about Cabosil? It's used to thicken rubber, it's made of ground glass.

Joanie: Oh that crap. Stay away from it. Moon dust. Tried it once. It's not safe, and not good. Try laying a strip of oil clay then painting over it with the rubber. Doesn't need much ridge, just something to 'register'.

Me: Is it OK for the clay to stay inside the rubber after the mold is made? Or do I need to get it out somehow?

Joanie: Should be okay. As long as it isn't too close to the inner surface. Might bulge inward if so. But won't hurt the mold long term. I think that I would try a long strip of something. Rope? Glue it on, paint over it well. Ponder that. :-)

Joanie: My other concern is how you have been told to mix the plaster. I find that method to be variable in the extreme. It's okay for art class, but not good enough for long term plaster strength. It's easier to do that method **if you already know how plaster is supposed to feel** LOL. In other words, it's okay if you have experience, but not if you don't.  

Plaster strength depends on three elements: 1. Ratio of plaster to water 2. Temperature of the water 3. Mixing time.

The ratio between plaster and water is 70:100 by weight. 70 parts water to 100 parts plaster. You can get away with 1 part water to 1 1/2 parts plaster if it's easier. I've started using grams because the math is easier. 700 grams water, plus 1000 grams plaster, equals 1700 grams total. You need a scale that does grams or ounces. It needs to go up to maybe five pounds? They're cheap and very useful. Slip a big ziplock bag over the scale, so that it stays clean and dry. Make sure to zero out your bowl first.

Water needs to be very warm, 100 or so degrees. Warmer water kicks it faster. Cooler water kicks it slower.

Slaking and mixing time is crucial. Slake for two minutes, before you mix. The most mixing in the least time will give you the strongest plaster.

Me: Question... do you mix the plaster and water with your hands (as it was suggested to me to do) or do you use a mixer? I'm guessing if speed is of the essence, you might use a mixer.

Joanie: Anything under 10# can be hand mixed. Main thing is keeping your hand down in it, and moving as briskly as possible without making bubbles. Wrist action. Knock the container against the table to raise the bubbles. Plaster is ready when a finger drawn across the surface leaves a wake.

Joanie: After you have slathered, glopped, and oozed the plaster onto the rubber mold, run a flat thing over the seam line to expose where the two plaster pieces meet. You can tell the different colors... you shouldn't have to attack the mold with a knife and hammer. 

Going back a little more, when you are pouring plaster against plaster, first make sure that your plaster is smooth. Make sure that your keys are smooth, round, and tapered. 

Then use mold soap as a separator. You can use Murphy's Oil Soap too but it has detergent in it. Vaseline will hurt the long term strength of your plaster. Rots it. Mold soap will make it stronger. Wipe on a coat of soap, let set a minute, wipe off with a barely damp sponge. Repeat three times.  You can see the satin sheen if it's right. Also, when soaping, use good sponges. You know the kind. Natural. One for soap, one for water. Wax on, wax off, Mr Myogi says. Never put the water sponge in the soap. Dilutes it. 

Me: How do you get the plaster smooth if it is already set? Or do you take down the divider while the plaster is still soft?

Joanie: You smooth the plaster with a tool. Take off the divider, then take a tool (such as a dental tool) and scrape it. That is the first thing I learned that set a light bulb off in my head when first learning to make molds. You **work the plaster** after it starts to set. If the plaster that you are pouring against is rough, or not well sealed, you're going to fight it. It doesn't have to be smooth smooth.... it only has to offer no resistance to being separated. Tool marks are okay, little indents are okay, but big bumps, holes, or wacky keys are not okay. 

Me: How do you fill any air holes in the plaster?

Joanie: If you have holes in the plaster, fill them with whatever. Clay, oil clay, whatever. You don't care if the oil clay stays in there. Makes no difference. But you DO care if the plaster breaks while you are trying to separate it. LOL

Joanie: I prefer to make my keys into my plaster after it has set. You can carve keys faster and better than you can sculpt them. Use a nickel, or a washer like you put on a bolt and nut. Turn it sideways and carve in with a twisting motion. Twist, twist, twist. You'll make a perfect, smooth key in no time. So for the plaster, don't be afraid to work it. Learn to love it in all of its loveliness.  

Me: When would you remove the clay dividing wall? I was told to remove it after the plaster started to cool. Would this allow me to work the plaster as you suggest, or should I remove the clay wall earlier?

Joanie:  When the chemical reaction starts, the plaster gets warm. It will still be soft enough to scrape with your fingernail, but it will be firm enough to stand on its own. Remove the clay dividing wall then. Usually, by the time I clean the bucket and my hands, take a sip of iced tea, and sit down again, I can start removing clay from the plaster. Depends on ambient temp of course, and thickness of casting. Thicker castings kick off faster and get warmer. The warmth (exotherm) keeps the cure going. But there is no rush. If it feels too soft yet, wait.

Carve your keys into it. Then let it cool for a while before doing the next one. If you are doing four plaster mold pieces total, you could do two that don't connect, first. Then the two that are between those other two. 

When you do those second two, you are pouring plaster against plaster. Use the soap. Wipe on, let set, wipe off. Three times. Then test with a fingertip of water. The water should sit on the surface and not penetrate at all. More soaping is always better if in doubt.   

When pouring plaster against rubber, plaster will not stick to silicone anyway, no need for a separator if what you are using is silicone or rubber. If you want to feel better about it, wipe one coat of soap over it.  

Joanie: This clean hands-and-buckets business with the plaster is nonsense. Plaster is made in a way that drives off one of the two chemically bonded water molecules, and by mixing water back in, you start a chemical reaction that rebonds. Now, if you have a sloppy, uncleaned bowl you will have bits of already catalyzed plaster floating around, but there isn't any sympathy between the plaster that has already started to kick, and the plaster that has not yet kicked.  

Joanie  If the plaster doesn't kick, its old. Throw it out. If it feels gritty, throw it out.

Plaster absorbs atmospheric moisture then is bad. It must be kept dry, sealed if possible. Just bought some plastic kibble bins with rubber seals around lid. Keeps it longer. 

Problem is that if plaster's old, you can't seal it and pour against it. Never could figure out why, but old plaster sticks to the next pour no matter how much soap you put in it. Ruin a few molds and you learn. Nothing like chiseling it all apart and losing everything.

Me: Ugh! So if it's bad, it can still set, but it won't seal?

Joanie: Yes. And you don't know for sure until your mold is made.

Me: That's good to know.... I guess... Is it better to use fresh plaster on a project just in case?

Joanie: Always. It's cheap. Time is more expensive.

And here we have the awe inspiring object for our first attempt, a Celluclay head meant to be a stand for my finished masks. I figure I'm not emotionally attached to it, so if I botch it nothing is lost, but if I can pull it off I will hopefully have a mold to make the stands a little bit easier to make. I've sanded the head down to smooth it out, glued it onto a piece of scrap lumber, sealed the whole arrangement with shellac and Johnson's paste wax, and then sprayed the whole thing with a light coat of Smooth On Universal Mold Release.

The next order of business is to make the rubber inner mold. It is what gives the cast its detail, and it is also flexible for easy removal from the cast after it has set.

In this pic the clay dividing wall has been applied, which will split the rubber mold in half from front to back. A key is also carved in to the dividing wall register the two halves of the mold together, and release applied to it as well.

Here we also have a gallon of fresh new mold rubber, Smooth On Brush On 35, which costs a cool hundred bucks and has a shelf life of six months at best after opening. Stress!! Part A looks like meringue gone  wrong, and Part B looks like drooling florescent green alien slime. And while this stuff is relatively benign for moldmaking material, Part A is one of those things to which one can easily become allergic (what's that called? A hypersensitizer?) so it's important to wear goggles, gloves and long sleeves while handling it.

Here we have the finished rubber on the front part of the head (pink) and the back part (grey.)

I watched and rewatched this video http://www.smooth-on.com/video_play.php?video_id=sOyBawt1-Ec&autoplay=1 , read and re read these instructions http://www.smooth-on.com/tb/files/Brush-On_Series.pdf and then I was ready to go.

Once the rubber starts going on, the clock starts ticking... after it's mixed, the rubber stays brushable for about twenty minutes, more or less, and then it turns into a solid mass. It's a trick not to mix more than is needed- this stuff is expensive!- or less- don't want to worry about a layer setting up too much while more is mixed.  About four to six layers need to be brushed on, each one right when the layer before it has set to the point where it is still tacky. Not runny, or the brush will just pick up and stir around the layer of rubber underneath the new layer, and not dry, or the layers risk delaminating later. 

I also added a few drops of paint to every other layer of rubber, so that I could tell more easily if I had covered the layer underneath adequately. Which is also why the two sides of the mold are different colors.

Once the plaster has started to cool down, the clay dividing wall can be removed, as shown here. Vaseline is applied to the exposed new plaster  and the last part of the mother mold applied. 

Good thing I had dutifully saved so many of my Nancy's Organic Yogurt containers as Nancy had instructed on the label. The plaster sets too fast to wash buckets in between batches, so it was very helpful just to have loads of clean buckets on hand.

Here the last part of the mother mold has been applied and allowed to set.

Now it's time to play hide and seek with the dividing line. I worked on gently finding the line (often betrayed by a little bit of Vaseline oozing out) and prying the pieces apart with craft knife, screwdriver, and tack hammer. I felt like I was an archaeologist on an archaeological dig.