So, I believe I have managed to replicate a clay mix created by the awesome Deskleaves
, called Derpentine.
It's a mix of polymer clay and two kinds of air dry: stone and paper clay as well as glue. The original recipe goes as follows:4 parts FIMO1 part paperclay1 part stoneclaya small amount of white craft glue
and can be found here: Adventures in sculpting 1
(clay recipe is (c) to Deskleaves
and if I see someone claiming it as their own I shall murder them so painfully and slowly they'll be literally able to feel each of their body cells dying o n e b y o n e...)
Now, I was making some Jonni's Air Dry clay [(c) to Jonni of www.ultimatepapermache.com/
] The recipe for that is:
24 grams of toilet paper, dissolved in water and drained until the combined weight is 110g
200g of acrylic joint compound
130g wood glue
3 tablespoons oil
+add more starch until it reaches perfect consistency
I typically add 3 tablespoons of vinegar to this recipe, in order to prevent molding.
Since, as you can see, Jonni's is both a stone clay (acrylic joint compound) AND a paperclay (toilet paper obvs), AND includes glue, I decided to try using it instead of all three ingredients, so the final recipe was:
2 parts polymer clay (old, stale Cernit One in my case)
1 part Jonni's Air Dry
Now, let's get on to some impressions of the clay after making it and playing with it for a while:
It took a very long time to mix. First of all because Cernit One is a very stiff clay and doesn't condition easily, so I had to knead it for what seemed like hours (in reality probably 20 minutes+). At first the clays did not want to mix, or so I thought. Then I noticed that the thinner ingredients of Jonni's (joint compound, glue) were being absorbed readily, while the paper tended to clump together at the top. The mixing process kept happening only on the surface, not reaching into the polymer clay. I kept on kneading it with seemingly little to no progress, until it suddenly went full 180 on me and turned soft and pliable within ten seconds or less. It was also at that point when the clay readily absorbed the paper fibers. After that point it took about a minute or two of continuous kneading to even out the color and consistency, as well as make the clay sticky. As soon as that happened, all the bits of clay that had become stuck on my hands before got quickly cleaned up and mixed into the clay.
The clay has remained sticky, which could probably be countered by reducing the amount of glue used for Jonni's recipe slightly. It does not, however, stick to hands or color them at all. It is incredibly soft and seems to be very fine grained. It holds detail astoundingly well, as it can be thinned down to well under 1mm and still easily stand upright. It catches and maintains any and all impressions readily, something to keep in mind as a great asset for detailed work, but a possible downside if you don't like to worry about leaving fingerprints in your creations. Despite having a definite bounce, the clay can be easily stretched. Its paper fiber content reveals itself then, making it streaky and rubber-like. Again, this could probably be countered by mixing the paper fibers more finely while making Jonni's clay. It is still incredibly easy to smooth. Unless freshly pulled, the clay appears shiny.
Here are some photos:
clay after rolling:
fingerprint left after pressing gently:
Piece under 1mm thick pinched:
Same piece in profile:
Result of stretching:
All in all, I'm pretty sure this clay has THE best properties I have encountered so far, beating all my current favorites.
AIR-DRYING (a separate piece, I am not air drying any other bits of this clay):
12 hours, clay is slightly more rubbery and appears darker in color. No visible change in volume, can be reconditioned easily.
24 hours, no change.
32 hours, no change
OVEN BAKING: 1 hour 20 minutes at 100C, no visible change in volume, no cracking, no apparent shrinkage. No discoloration observable. While still hot the clay is fairly soft, rubbery. Does not pick up impressions easily and cannot be shaped, but can easily be scratched or dented with a fingernail. As it cools it feels way more solid, but still flexible. Very similar to thick rubber. Easily sandable but doesn't smooth completely as it remains slightly scratched and a lighter color (as is to be expected from polymer clay). Much like polymer, it can be smoothed completely and made shiny by rubbing with a bit of vaseline. Educated guess is the air-dry components and glue have solidified, but plasticizer from the polymer is still present.
15 minutes at 130C. Fresh clay shows a single crack across the whole piece and some swelling, both indicating the "slo-mo explosion" effect (water in the clay boiling and expanding while baking above 100C). It was possible to push the crack back together and it has remained in place since. The clay that was pre-dried at 100C shows no such signs. No shrinkage in either piece. Both appear to have mostly the same properties. Clay is more solid than after baking at 100C, but still slightly flexible. Despite feeling rubbery to the touch, it's impossible to dent by pushing into it, only shows flexibility when the whole part is bent. Overall it's about as, or slightly less flexible than the original polymer after baking, meaning that air-dry clay does add rigidity to the mixture.
30 minutes at 130C (two times 15 minutes) the clay is actually more flexible now? And kinda wants to tear when bent? What is happening?? I think the polymer went more rigid but as a result the air-dry is now damagind to the integrity? It's probably better to only bake for 15 minutes.
Oven-drying identical, 3 gram pieces of Derpentine mix, derpentine with commercial mineral/paper clay (Darwi Roc) and all ingredients separately, compare their properties after a few different time intervals (15 min, 15min, 30min, so one hour total)
derpentine - appears solid
derpentine Roc - slightly less solid, wanting to tear a little
Cernit One - appears solid, but more flexible than either derpentine
Jonni's - still soft, wet, crumbly
Darwi Roc - appears solid, but wet on the inside, could be crushed/crumbled
derpentine - fairly bendy, difficult to break
derpentine Roc - similar to the other derpentine but still more brittle than flexible, kinda wants to tear still
Cernit One - more solid than either derpentine, almost impossible to bend, not tearing/cracking
Jonni's - about the same as Roc 15 minutes earlier, solid on top and still wet inside
Darwi Roc - fully dry and solid, hard and durable like a rock
derpentine - bends ever so slightly instead of breaking or tearing, but in general is barely flexible
derpentine Roc - got eaten by one of my dogs
Cernit One - solid
Jonni's - solid, hard, neither bendy nor crumbly
Darwi Roc - still rock hard, you could probably kill someone with the sharp edge
recommendation: Pre-dry at 100C before baking; Possibly only use pre-drying while working on the sculpture, and only bake the finished product once. Air drying appears to have no effect either way, so pieces can but don't have to be left out before baking