Molding Quick Links Molding Quick Tips

Removing the Armature

- Sometimes the armature can be difficult to remove. You may have to use a loop tool or a wooden sculpting tool to carve out some clay around the sides of the armature.

- I used a hack saw to cut the ears of my armature as I always had problems with the ears on my armature getting caught in the mold.

- Use wooden tools or a wooden tooth pick to remove clay, this will ensure you don't scrathc up your mold wall while removing the clay.

 

 

Mold Making Process - Pt. 3

The final step in the mold making process is to crack the mold and clean it out. We’re not actually “cracking” or breaking the mold, so much as separating the front and back halves. Once the two halves have been separated, our goal is to remove the armature and clean out the clay.

I like to wait about an hour after finishing making the mold to pry it apart. This gives the Ultra-Cal enough time to set up, but the sculpture underneath should still be good and soft. It’s much easier to clean out soft clay from the mold.

Step 8 - Cracking the Mold Open

Separating the two halves of the mold is our first task. This is done by inserting pry bars or large flat-head screwdrivers into the slots we created with our small clay wedges before we cast the front half of the mold.

It helps the process to pry from two slots at once. I begin on one side and start to pry and I move my pry bars around to other slots and continue to pry. Don’t try to separate the sides all at once.

Be patient and pry from each of the slots and eventually the mold will separate. If you are too aggressive with your mold it can crack into pieces and you can end up losing the whole thing!

Typically the back half of the mold comes lose first. This is because it has less undercuts and detail than the front half of the sculpture.

When the back half has been removed, our next step is to remove the armature. Many times it is necessary to remove some clay from around the sides or top of the armature to help free it up.

Step 9 – Cleaning the Mold

After we have the two sides of the mold separated it’s time to clean out the clay.

The back half is usually very easy to clean out, and you’ll find the clay will come out in nice large chunks. If you have some stubborn small pieces you can use a wooden sculpting tool or tooth pick to help clean it out. Try not to use metal tools for this, you’ll run the risk of scratching up the mold or ruining your detail. Any small left over clay can be cleaned out with a tooth brush and water.

The front half takes a bit more time and care to clean due to all the under cuts and detail, but I follow the same steps as I did for the back half. Remove as much clay as possible with fingers and wooden sculpture tools. And again, use a tooth pick or tooth brush and water for the rest.

I will typically give both halves of the mold a good spraying with a garden hose to remove any small bits of remaining clay.

Step 10 – Patching the Mold

After the mold has been cleaned I’ll mix up a very small batch of Ultra-Cal into a cup to patch up any air bubbles.

In addition, I’ll strap my mold together using tension straps or plain old duct tape and fill the mold seam using very small amounts of Ultra-Cal and my finger. Try not to use too much, or you’ll end up covering up your detail.