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This is the instructor's thread for the third project of 2016, Molding a Skull. UnOrthodOx is the instructor and he will be posting the materials list and start date soon.. Please note this thread is for the instructor's use only. Please post all questions and comments in the student's thread found here.
 

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Good morning everyone!

My goal here, having penned 2 previous tutorials on the topic, is to provide a dead simple, my 8 year olds did it this way, means for ANYONE to make a mold and start making their own skulls.

As such, it's going to be a little more trimmed down than my last tutorial, and going to focus on just a good, basic mold and cast.

That said, our shopping list:


1: Mold builder latex. This is available at Michaels. At the time of this writing, it'll run you about $16, so you're going to want to take one of them coupons with you. We'll be using 3/4 of the bottle, up to the full thing, depending on how thick and how big your skull is.



2: Paint Brush. This will likely get ruined, though type recommendations coming later today. Available at Michaels.

3: Cheese cloth. Also available at Michaels. Small scraps are all that is needed, just get a cheap pack if you don't have any on hand.

4: A Skull. You need a skull to start with. Plastic works great. Bone works. Plaster works. Wood works. Glass, sure. Try to get one without the cut cavernum (top of the skull comes off).

What won't work: those cheap Styrofoam skulls will likely get destroyed when we peel the mold off. Latex skulls will not work, period.

Prop-skull-1 here is what I started with, and have used for ages:
http://www.fxsupply.com/pl/pl_docs/skull.pdf


5: Some clay. Recommend either DAS or some Model Magic. Both available at Michaels.

6: Plaster of Paris. Also available at Michaels, but cheaper at your local hardware store.

That's it, 6 items.

Now, go get shopping and get ready to get to work! We'll start work this coming weekend 5-7. Expect it to take 1-2 weeks to make a mold, and an hour to make a skull once the mold is made.
 

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STEP 1: MODEL PREP


Alright, before we get to making a mold, we need to prepare the model.

I've chosen this particular model as it had the most areas that needed attention to show you guys what to look for.





Now, anywhere there is a hole, we've got to take some of our clay and patch it up.

Eyes:



This model has holes in the teeth:



And the zygomatic arch:



You DO NOT need to plug the Foramen Magnum (big hole at on the bottom for the spinal chord):




Just take your clay and press into the offending areas:



A note on the zygomatic arch, you want it about as thick as the bones or this area will break when we start casting.



For my teeth, I just pressed clay into the back side. This leaves the detail up front and makes the teeth a little thicker for easier casting later.



We want this clay to dry, and to patch up any holes that occur from shrinkage before moving on.
 

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Some models will have additional holes. Here is the Lindberg model, note additional holes plugged underneath.



Nasal passage plugged on the lindberg:



*advanced* With a little experience, taking this method to the extreme, keep in mind any really deep holes, you'll have to balance realism for what will work. Here is a bear skull I actually molded via this method. The nasal passage, having the clay deep enough to not be noticeable, but still able to work as a mold.

 

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Step 2: Latex base

Once your clay is dry, it's time to start the latex. This will happen over several days, so have patience, and plan on a week. Maybe more if your weather sucks.

Recommended brushes updated above, but I'll reiterate here:

Synthetic flat brushes tend to not get ruined as quickly/easily with the latex.

http://www.michaels.com/artists-loft-necessities-white-synthetic-flat-brushes/10183006.html#pmpt=qualifying&start=18

Where natural fiber brushes will tend to dry out the latex as you're brushing and you soon have a latex gob in your hand rather than a brush.

Mold builder has changed it's formula in the last few years, and it now goes on much smoother than in the past, making this process easier.

Your first coat, you just want a thin layer of latex, being careful to coat everything and keep as much detail as possible. The latex will be very nearly clear when it dries at this stage, but it's fairly fragile and awful sticky as well, so be careful not to try to touch anywhere you've brushed.

The best way to manage this is to tackle this in 2-3 steps, setting the skull down on the table to coat the top, letting that dry, and then turning it over to reach the areas you haven't brushed yet.

[/img]https://lh3.googleusercontent.com/-MhnM-UEs8JM/VRTQD0b-CfI/AAAAAAAAdJI/mKJSvu-OmhsAJ8kBKlV6a1eoBQ5bx3PegCCo/s800/IMGP6395.jpg[/img]

I use a bowl to hold the skull while I paint the bottom.



Speaking of that bottom, you need to leave yourself room to pour in plaster on the mold. I like to leave an oval from the back of the Foramen Magnum around the sides, and up to the back of the palate





Second and third coats can be put on thicker, but you don't want to have a lot of runs either. With the new formula of mold builder, you're better off making 4-5 thin coats than 3 thick ones. Personally, it depends on what my time is. A thin coat can dry in a few hours, if I'll be around to recoat at that time, I'll go thin. If I'm going to be gone for 12 hours or so, I'll do a thick coat. If you get a bubble in a layer, you'll want to pop it with a pin before adding the next layer.

You can tell where the molds are thin by how clear they are. (clear areas thin, needing another coat, white areas not dry, don't touch)


Just keep adding coats and building up your mold until you are 1/2-3/4 the way through our jar of mold builder.
 

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Step 3: Cheese Cloth


By now you should have a nice thick coat of latex over your skull, and used half, to just over half your latex.

We want to add cheese cloth to the face and top, all the way back to the widest part of the skull.

To do this, cut your cheese cloth to the desired lengths/shapes. Then brush on a thin coat of latex on.



We then apply the cheese cloth and cover again with latex. I use several small pieces at the face. (one for each eye, one for nose, etc) Use your brush to push the cheese cloth into hard to reach areas. No bonus points for pretty at this point.



LET THIS DRY fully.

Inspect your skull and mold for any thin portions, especially on areas not reinforced by latex.

Here you'll not the more see-through areas on my mold here, I'll go add additional coats to firm those up.



Again, it's critical to allow this latex to dry fully before removing it from your skull.

REMOVAL:

Starting at the back of the neck, roll the mold forward. You might hear some tearing of the cheese cloth, that's fine. The inside will likely be sticky as well. Once you pull the mold completely out, either dust it with some corn starch or leave it inside out to dry for a day before attempting to make copies.



We'll get to making copies by the weekend.
 

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Hey, I'm still playing the "I'm new here" card, but what happened to the rest of this thread? I need to know what happens next!!!!
 
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