Tuesday, November 24, 2009

Curing tips for air dry clays

The following tips are excerpts from the book  Fantastic Figures: Ideas and Techniques Using the New Clays by the late and great Susanna Oroyen.
"When I asked other artists how they proceed, I found about half work pretty much as I do. The rest do all kinds of interesting things....The following descriptions apply most specifically to Creative Paperclay, but the basic techniques and effects are approximately the
same for all these (air-dry clay) products."

Curing

Air dry clays ......"start the curing process the minute the package is opened, when the moist product is exposed to air. There is no great mystery of technique involved in curing paperclay. Your job in working with the paperclays is to stop the natural curing process until you have completed the sculpture and you are ready to let it dry. It will pay to understand how the product reacts to air over the period of drying, as this can affect how you work."

"Suppose you have modeled your sculpture over a foil or Styrofoam ball, and the paperclay is about 1/4" thick. If you leave that, it might appear dry in 8 to 12 hours. However, even when the exterior of a piece looks and feels dry, the interior may be quite wet. Three or four days later, you could cut into the piece or remove the core and find the interior still quite damp. This is, in part, because the dry exterior surface serves to seal in moisture. I have talked to artists who modeled over foil or foam, dried overnight, painted and finished the surface in the following 48 hours. This worries me, as I have found that even a hollowed-out piece, where air can freely circulate to the interior, can take up to three days to dry completely. Therefore, be very aware of how long it might take to dry the interior of your pieces, and do not go on to finish and seal the work until you are positive it is thoroughly dry."

"Since the paperclay is drying from the outside to the inside, it forms a slow crust. If you work the dry surface, you will find that this crust can peel off.  You will also find that the crust is rubbery.  It is not unusual during this period to have the surface crack and the whole piece bend at the same time." ......"One positive aspect of paperclay is that it can be moistened and re-sculpted after being dried.  Just take your time."

"I prefer to keep my work very wet until I am totally satisfied with the sculpture.  Then I let it dry thoroughly. When it is thoroughly dried, I re-work, clean, patch, or repair as needed." .... "An alternative approach is to build the paperclay sculpture over the armature very slowing, letting each layer dry before you add the next. If you apply multiple thin layers, when you are ready to let the piece finally dry, only the top layer will need drying."....."The time involved will be about the same with either approach."

"In either the wet or dry approaches with paperclay, no matter how careful you are, the material is exposed to air as you work. The exposed surface will always be drying..... The material will even be drawn dry by your hands as you work it. This is why you keep a spray bottle of water handy. Just a quick squirt from time to time - not a soaking - will keep material workable."

"Just because paperclay tends to dry once it is out of the package does not mean you have to work fast. You can keep work in process for days and weeks if you keep it damp while you are working and cover it well when you are not".

I (Mary) prefer to use the approach where you let each layer dry and build on it.  This allows me to continue working on the same figure for weeks at a time, or to work on more than one at a time without worrying if I'm keeping it damp enough.    Please comment if you have any ADC curing tips to share.

Image credits:   Photos are all dolls created by Susanna Oroyan


5 comments:

  1. I use polymer clay to make teeth and claws for paper mache dragons. I recently tried a brand called "Lumina" but the results were disappointing. It just won't harden. I know it should stay somewhat flexible, but this never got even close to hard. Are there air dry polymer products out there that will get really hard and durable for sharp objects, like claws?
    Thank you.

    ReplyDelete
  2. Hello Dan! Love your sculpts! Very creative! Lumina is an air-dry clay which is designed to remain flexible so is probably not the best choice. (Click on keyword "Lumina" in sidebar for more info.) The hardest air-dry clays I've used are the "stone-based" clays such as LaDoll and LaDoll Premier (Premier being firmer in texture & stronger/harder when cured). Creative Paperclay will get quite smooth and hard with repeated sanding and polishing (super fine grit) of cured surface. Paperclay is a good compliment to papier mache, worth giving it a toothy audition!

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  3. PS to Dan's question! From what I've read, it seems all the POLYMER or resin based air-dry clays are practically always a bit softer when cured than other types of air-dry clay.

    ReplyDelete
  4. This may be off topic, so I apologise if it is...

    Is stone clay, like La Doll Premier, alright to get wet after completely cured, or will it soften and ruin the sculpt? I'm asking because I want to do a mockup on a doll I'm planning on sculpting with epoxy, and see no reason to throw away a clay doll if I could instead give it to someone who would enjoy it when I'm done with it. However I'd like to be able to tell them whether or not they should beware of water.

    ReplyDelete
    Replies
    1. Beware of water but keep the doll. Protect from dampness & dirt with a matte sealer/topcoat. LaDoll is a top quality clay and can be polished to a very hard surface but still should have some kind of protective coating. LaDoll is often the clay of choice for the extremely complicated BJD dolls.

      Delete

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