Thursday, June 23, 2011


I promised this to Betty Lou and I finally got around to doing it so here goes.
Polymer clay is wonderful stuff. It has a good deal of strength on its own but we can increase the strength of the final product by doing two things; cold bath and super heat.
We have touched on these two procedures before in past postings but it never hurts to do it again.
COLD BATH is simply taking the figure out of the oven while it is hot (just as the curing cycle ends) and placing it in the freezer, refrigerator, snow bank, etc. The idea is to drop the temperature as fast as you can. This will help stop cracks from the cooling process. It works, I have done over 70 pieces this way by now. I used to use a cold water bath but no longer do as it is hard to get the water out of these small figures and polymer clay grows mold very well.
SUPER HEATING adds additional flexibility and strength to the clay.
 STEP 1: Sculpt your piece. Here I have done a fast sculpt of a male hand to demonstrate. You need to pay attention to the sheen on the surface of the clay as we progress. This shiny clay is uncured at this point; notice the sheen to the surface.
Be sure all sharp ridges are smoothed down before curing. These ridges will scorch when you hit them with the heat gun.

STEP 2: Bake at the clay manufacturers recommendations. This is the same hand after curing in the oven. Baked clay will have a "flat" appearance. There is a little shine to the clay but not as much as the raw clay shows.

STEP 3; Super heat the clay. Use a standard heat gun (paint stripper) to super heat the clay. Stay about 4" away from the clay and keep the gun moving around. Focus the heat on the bulk of the hand, not the fingers. You need to alter the structure of the hand as well as the fingers or they will just snap at the base of the finger where they meet the "old"clay. Once the hand is heated you will move up the fingers to superheat them as well. This will take about 45 seconds to do a hand.
This is the super heated hand. Note the sheen to the surface. This is the end point you want to reach.
BE CAREFUL! The gun can reach temps of 1,000 degrees so it will scorch and burn if you are not careful! (see the little scorch mark on the back of the hand)

The images below show how much bend you can get when you super heat. This is done while still warm from the process. Once they cool, they will have less bend but still resist breaking .


  1. WOW...thanks Mark!! I so need to get a heat gun now.

  2. Wow.... that is incredible!! When you have a chance, Mark, could you kindly tell me which heat gun you recommend ?
    Many thanks for all that you do for us. I really appreciate it!!
    Big hugs,
    carla g. Incantostudios

  3. Incredible! I fear the burn everything! But this can also be done on prosculpt pure?

  4. Thank you for posting this. After super heating, do you do the cool bath method or let it cool on its own?

    Since I'm new at this, I tend to series bake i.e. sculpt head and bake, add to armature and do the torso and bake, then add arms and legs, etc. so I don't destroy what I've worked on previously. I sometimes wonder if my additions are as strong. Maybe super heating those areas will help.

    Do you have an opinion about series baking and whether it makes the figure weaker?

    Thank you.


  5. Carla, I recommend any heat gun from a hardware store. They get hotter than embossing guns and are build to last. Mine is a Wagner power stripper and I have had it for about 15 years now.
    Alessandra, The same technique works on Caucasian ProSculpt but the clay will darken. This is why I have switched to Baby ProSculpt.
    Marlene, After super heating, I let it cool on its own. Series baking works fine. Just be sure to use a wetting agent (like translucent Liquid Sculpy or smoothing oil)when applying new clay to cured clay.

  6. This is great information, and I will soon be making my own quick hand to test it out.

    Just one question - do you do both the cold bath and the superheat on the same piece? Or do you choose just one or the other?

    If you do both processes I take it the cold bath would come after step 2...correct?

    Thanks again
    - Julie

  7. Thanks Mark! Then you advise me to use baby prosculpt only limbs that will be heated before reaching the color of Caucasian prosculpt the rest of the body. Or use only the prosculpt baby? Thanks for the time you spend there.

  8. I recommend that you not use the Caucasian prosculpt as it changes color when superheated. Use the Baby formula.

  9. Wow, this is a great tip! I am going to do this to my current sculpture. I want the fingers to be splayed out on one hand and have been worried about breakage. Thank you for sharing!

  10. Thanks for sharing this tip! My figures break and crack all the time and it drives me nuts. Do you wait for the piece to cool down first before superheating it or do you superheat it right after it comes out of the oven and while it's still warm?

  11. Mark, you are a font of information and an amazing master!! Thanks for posting this. Am I guessing correctly that there is no thin armature wire in these fingers? May seem obvious that there is not, but didn't want to assume.

  12. You are remarkably generous and for that I , and many others owe you a hearty thanks. Your work is wonderful and born of your beautiful spirit

  13. I used to use a butane lighter to do this also, but the heat gun would give better control as the butane lighter burns the clay if ur not very very careful.