Sunday, April 17, 2011

Head (or other parts)Cracking Issues

In a previous posts, Fran asked about getting cracks in the finished head. After about 300 figures now, I have found that it is important to keep your clay covered with plastic after sculpting the face; or the rest of the figure for that matter. Polymer clay loses oils as it sits out in the open. The longer it sits around, the more crumbly and cracked the clay will become. I use a polymer clay skull under my faces which sucks even more oils out of the clay if it sits around too long.

This head was sculpted then sat in a sealed baggie for about a month before curing. The entire backside of the head is covered in a pattern of cracks. In most cases, I would throw this out but the piece I am working on is going to be a bit dirty and unusual (for me anyway) so I can use the head with a few repairs. In fact, I want to give his face a scar so this will be fine to repair and use.
 The first step is to remove the square edges on the sides of the cracks by using a sharp blade to bevel each side.
A very thin coat of Liquid Sculpy is brushed into the crack and onto the surface of the head. This product puffs up as it cures so if you put too much in, the repair will rise above the surface of the skin and look like a raised scar. (Good to know if you want scars)

 The cracks are filled with clay.
The surface of the repair is blended into the surface of the head. The finished repair is cured with a heat gun.
The repaired head is attached to the body I made last night and is ready to go into the oven to cure.
The repair will show but they can be covered well with washes of color. This head was sculpted out of ProSculpt Caucasian clay and repaired with ProSculpt Baby clay so there will always be a difference in the color. Again, for this piece it will only add to the feel of the finished piece but for a pretty lady, I would start from scratch.

Generally, I prefer to sculpt a piece on the first day then let it sit overnight under a plastic bag to keep the oils in and the dog hair out. The second day I make changes to the piece and cure in the oven. This way my clay does not start to dry out so I help to minimize the chance of cracks.
Hope this helps. Have a great day!


  1. ahhhh..thank you for the info. Something you can never have to much of. ^_^

  2. That's a good idea! I have noticed how good TLS is for covering cracks.

    P.S. I am just curious - is your work base made of wood covered with masking tape...? I'm just wondering what the masking tape would be for. =)

  3. Thank you for saying the clay dries out. Everyone I ever asked said it never does. I think it gets old too. I got some Cernit that I had to beat with a hammer between plastic to get it pliable enough to manipulate. Does Sculpey clay softener attach the new clay without puffing?

  4. Thank you, thank you! Great site! I have liquid sculpey around here, somewhere...

  5. Alex, The sculpting base is a piece of aluminum which I cover with tape to keep the oxidation from getting my clay dirty. It can go into the oven and is heavy enough to hold most pieces until I chose a final base for them.
    Wicked, Clay softener will also work without the puffing issue as will mineral oil. Again, use just enough to wet the clay.