You can use any material under/inside polymer clay that can take the low heat necessary for curing polymer clay (around 275 F). Those armatures inside the clay will also be insulated from direct heat and so not get too hot as easily as the clay outside.
Air-dry clays and papier mache, etc, are commonly used as permanent armatures under polymer clay, but not sure how much "stone" or other kinds of filler Stonex has in it, etc, and stone might expand or contract a bit during heating/cooling and cause cracking in a polymer clay covering. (You won't heating the air-dry or polymer clays or the armatures to really high temps by kiln-firing, so no worries there.)
First, the brand of liquid polymer clay made by the manufacturers of Fimo (Fimo Liquid Decorating Gel, or Deko Gel, etc) has been discontinued. You may see old stock of it here and there, but generally it won't be available. There are two other brands of liquid polymer clay still available though, the Sculpey one and the Kato one (which is clearer, thinner, more heat-resistant, etc). All brands of liquid polymer clay can be mixed with all brands and lines of polymer clay though, and all brands/lines of solid polymer clay can also be mixed together (resulting in a new mix with characteristics proportional to the amount of each clay used).
You can read a lot of good info about liquid polymer clays, get lessons for using it, the various brands, etc, on this page at my site (but I haven't kept the site up for a few years so some things may be different, links broken, etc): http://glassattic.com/polymer/LiquidSculpey.htm
And if you're a newbie, you might be interested in other aspects/lessons/etc re polymer clay too. You can check out all the polymer clay topics covered at my site from the Table of Contents page: http://glassattic.com/polymer/contents.htm
I *think* you are wanting a material that you can create an impression in (like handprint or footprint) then harden, and not to later use that hardened impression as a mold to cast some other material in.
If that's the case people often use polymer clay, and for that purpose most often they'll use the brand/line of it called original plain Sculpey (which comes in a box) --mostly because it's cheap and white. The kits you'll see for doing that at home usually use Sculpey, but include a frame to put the clay in, etc. (you can use a frame of your own). Because that particular line of polymer clay is somewhat brittle after hardening (in the oven) when thin, baked slabs of it could be broken if stressed much so best to put the clay on the backing in a frame or on something else like a plaque/etc to give it more strength and protect it from getting stressed.
Polymer clay doesn't have to be mixed with anything, and it will never harden until it's heated sufficiently (unlike air-dry clays). Also polymer clay will take and hold details much better than most air-dry clays, although the softest polymer clays will sometimes not create or hold those details as well as the regular brands/lines (like Premo, Kato Polyclay, FimoClassic, and Cernit--sometimes FimoSoft is okay).
As for sensitive skin, that might depend on just what you mean by sensitive --a normal baby?, a person with many allergies?, etc. A few people may react to raw polymer clay; if that's the case, they'll usually try a barrier cream and then gloves of some kind (if they're allergic to latex, there are others). You can read all about those things on this page of my site: http://glassattic.com/polymer/safety_health_cleaning.htm (click on Rashes & Allergic Reactions) (Normal babies and kids would be fine for doing the handprints though. Just wash their hands afterward--and before they can put them in their mouths though not "toxic" even then.)
If you don't want to use polymer clay, some air-dry clays will be better quality than others (e.g., Creative Paperclay), and even some grain-based homemade clays should do well enough though all air-dry clays will shrink a bit while drying--like salt dough clay (...and btw purchased Play Doh isn't grain-based, though some homemade "play doughs" are).
If those don't answer your questions, ask here again with more detail and I'll try to remember to check.
There are various sharp blades sold for cutting polymer clay canes, and many clayers like the original blade we used--a tissue blade for cutting stuff in pathology. Generally, you'll want a medium to long blade for cutting canes unless those canes are tiny or baked, and should be quite sharp. Most will be flexible too.
The best way to firm up canes for slicing is to let them sit overnight, but chilling in the freezer or frig awhile can be helpful too.
As for making slices all the same width, there are ways to mark canes or just use a ruler of some kind (even one you make yourself), but generally clayers get close enough with practice and usually a bit of variation in thickness won't matter. Practice and a few tips can help make "even" slices too, the same thickness throughout.
Brand and line of polymer clay can make a difference too re ease of slicing without distortion.
The main reason you're probably thinking of is *safety* (for use later with food or cooking). That's not really a problem in your case though because your surface is not porous, and there are no little crevices in it where the clay/plasticizer could get trapped and be hard to remove. (So just wash your baking tray with soap and water well or wipe with alcohol till clean.)
Other factors can apply to metal baking trays and polymer clay though when curing especially: ...One is that if polymer clay is baked *in direct contact* with a very smooth surface (metal or aluminum foil, glass, ceramic, etc), it will have a shiny spot in those particular areas after baking. That's because polymer clay softens slightly when heated but enough to take on the surface texture of anything it's touching. ...The other one is that metals and ceramics, for example, *can* heat up higher than the oven cavity's air temp and therefore darken the bottom of the baking item or just speed up baking from one side.
For both problems, you can just place a sheet of plain white paper on top of the metal tray then place your item on that when ready to bake. Paper has approximately the same surface texture of baked polymer clay. You can even accordion-fold the paper for baking beads, pens and some other items. Other materials will work too under (or over or around) the clay, and especially when you're trying to "protect" the clay from darkening, etc, while baking. There's much more info about ways to protect the clay while baking, baking surfaces, safety, and more on the Baking page of my site, if you're interested: http://glassattic.com/polymer/baking.htm
P.S. Polymer clay is not "toxic" in the true sense of that word--well, unless you burned it, passed out, and breathed the thick black choking smoke for long enough to kill you.
--blending the join between the two butted ends is almost impossible to do neatly!
It's helpful to cut the ends at a slant rather than straight across, and then lightly press/wiggle and even stroke them lightly together to join the seam. (If any smearing occurs, it can be sanded off later**.) You can do that with 2 ends by overlapping them side-by-side, then cutting through both at the same time (on an angle) with a long sharp blade; then joining.
Even when joining clay rod ends that have been cut straight across, you can press them together a bit then pick up and gently roll the join between your fingers rather than just rolling it on your work surface. Also letting the clay parts sit together awhile (even overnight) will increase the strength of the bond by letting plasticizers from each end leach into the other end, or you can try putting a tad of liquid clay on one side or Diluent (now called Sculpey Clay Softener) tho best to let absorb a bit, or just rub each side gently to warm and soften a little.
The rest of any shaping is just kind of pressing or rolling around or on the surface, etc, till the join looks good and is the same diameter as the rest of the rod/bangle.
Or you can do what some clayers do which is just to put another bit of clay around the join so the seam won't show at all. You'll see some instances of that in the links above.
--after wrapping on can, any attempts to texture, decorate, or even join the clay made it stretch bigger, becoming loose on the can
Texturing and embellishing the clay is often done before making it into a circle and baking. Those things can also be done on the form (cylinder, rod) but if you're using a soft clay (Sculpey III, Craftsmart, or even FimoSoft especially) they'll more easily distort and stretch and especially if warm..those first 2 shouldn't be used for bangles at all though since they're weak after baking in any thin areas and bangles are "thin".
If you want to do those things while the clay is on the form, make sure to use a form that's rigid (not like a toilet paper tube or even empty aluminum soda can--maybe a stiffer metal like a regular food can, or fill your soda can with water--it can be baked with the water), and also perhaps even smooth (like metal, etc) so that the clay will tend to stick to it and not stretch as long as your texturing/etc is applied straight down (and gently).
--with many bracelets on one can, there was the risk of bracelets shimmying down can during baking, and touching each other
If you want to bake more than one bangle at a time, you could use more than one can (preferably a stiff-metal can) or that one can could be cut into segments.
You could also lay the can down while baking (preferably on a nest of polyester fiberfill or pile of baking soda to retain the bottom clay's shape while it bakes--and softens), or you could make some kind of horizontal rod or cording it could hang through while baking.
You could also put something between the bangles on the can, but nothing that would leave an impression when the clay softens during baking --perhaps a strip of polyester batting, or a tissue or piece of cotton fabric folded-over to make a strip, or something else.
So far, they DO seem sturdy (baked a couple times for extra hardness), but i feel that i have little control using this method.
Baking any polymer clay longer will polymerize it more and more and therefore make it stronger (though more likely to darken if not protected***), but it's also important to use brands/lines of polymer clay that will be strong enough after baking when they're used for "thin" items like this. So as mentioned above, Sculpey III is not a good choice even though it will feel "harder" than the strong brands; Kato Polyclay and FimoClassic will be strongest, followed by Premo and Cernit. FimoSoft is not quite as strong.
(Not sure what you mean in this sentence by having "little control using this method.")
You might want to look into the other ways of making bangles with polymer clay, which include all kinds of methods like making the bracelet in two parts with a hole or channel running inside each one, then using elastic or two elastics through them both; making the bracelets over a pre-baked polymer core, or over a non-clay armature of some kind; making the bangle flat on the inside; etc.
And you can get lots of info on making bangles in all kinds of ways as well as other polymer clay bracelets, if you're interested, on this page of my site: http://glassattic.com/polymer/jewelry.htm ...for the type you're doing, click especially on "Cuffs" under the Bracelet category (though unfortunately many of the actual links have been broken by their owners)
No problem baking almost anything with polymer clay, especially because of the low temps necessary to cure it.
The only materials that wouldn't be advisable would be the kinds of plastic that soften, shrink or melt at 275 F or above, and even some of those will work if they're well protected so the temp goes no higher at any point.
Materials that could contain any moisture (and haven't been sealed or dried sufficiently) would also be a problem but those would just cause steam and swelling under the clay and perhaps plaques that would show, as opposed to being a problem in themselves (e.g., bare wood, twigs, etc, if not painted or coated with clear sealer).
As for making the flowers and hanging right, are you saying each flower doesn't "hang" right, or that the entire cake/vase/flower dangle won't hang vertically? If it's the flowers, are you putting each on the end of a thin and semi-rigid wire so they'll stay just where you want in the arrangement?... like this: http://s96.photobucket.com/albums/l163/DianeBB/minatures_more (click on the arrangement on left)
If it's the whole thing, you could perhaps make the cake with a weight inside so that the whole thing would hang vertically. That would happen even better if you use a really long head pin to go down between the flowers, through the vase, and through the cake (then create a loop in the top of the wire for your dangle loop), or just use a length of wire instead or the head pin.
You could use Pluffy for the flowers but that line doesn't take very much detail so the flowers would have to be non-delicate or non-well-defined ones. Regular polymer clay flowers atop good wires shouldn't add much weight since they're so small, I'd think. Or since the flowers in your pic are kind of tight together almost like a nosegay, you could use a blob of clay in the center for the wires to go into or even have some of the flowers directly on the blob or have some of the flowers touching each other for more stabilization of positions.
I can't see close enough to tell, but looks like one of the polymer clays. It's probably "Pearl" with another color mixed into it by the maker** (Pearl is the mica-containing polymer clay which has no added color--like gold, copper, or even blue/red/green.)
Pearl is put out by various brands and lines of polymer clay but not all polymer clays are the same quality, working capabilities, strengths, etc.**. Fimo is one brand that puts out mica-containing clays under their FimoSoft line (some pre-colored I think, as well as their "Mother of Pearl"). They also make clays with glitter in them which often won't look the same but can create interesting glittery effects if the glitter is microfine--those won't do all the special tricks** that mica-containing clays can do though when used alone...you can't even see those effects in this sample.
** on this page and the next few pages there, you can see examples of Pearl colored by the clayer (with different colors) as well as some of the special tricks it can do: http://www.clayfactory.net/pier/PIER1.htm
I can answer all those questions, and also direct you to my polymer clay "encyclopedia" site for loads of info on all aspects of working with polymer clay (be back in 20 min or so with all that).
But wanted to say quickly that the most active board for polymer clay here at Craftster is the Completed Projects sub-board: http://www.craftster.org/forum/index.php?board=238.0 Occasional questions and discussions happen on this sub-board but it doesn't have nearly as many posts. Be aware though that at Craftster it's mostly sculpts that are shown and discussed, and only a few of the many other things that polymer clay can do (there are other boards/groups I can direct you to for those). +++++++++++++++++++++++
As you'll read, the "best" two remaining brands/lines of polymer clay on the market these days are Kato Polyclay and FimoClassic, though many clayers are also happy with Premo and Cernit. I wouldn't bother with the others, except perhaps for specialty ones if needed, if you're serious about doing all kinds of polymer clay on a somewhat higher level.
Kato Polyclay is more used than FimoClassic now that the manufacturers of Fimo have started focusing on their FimoSoft line and also moved most of their colors to the FS line or dropped them altogether. FC can be a bit harder in the package too, though not always, but good conditioning techniques can take care of that. ....Kato Polyclay does have a slight odor that a few clayers have found objectionable, described as sort of a "new vinyl doll" odor (unless that's changed), so you might want to check out some of the Kato clay to see how you get used to that before committing completely. ....Kato also has only 8 main colors (plus translucent and metallics/pearl, as well as liquid clays, etc), so unless you're okay with being limited to only the 8 spectral colors, you'd be mixing your own colors (most more-advanced clayers do that anyway though--with a pasta machine). Kato colors are easy to mix though because they're very pure colors (Premo is better at that too). ....Donna (Kato) has a particular way of conditioning her clay which you can read about on the Conditioning page of my site, but basically like all the better/firmer clays you'll just want to use a pasta machine and put in only thinner slabs of clay to begin with. Like any firm raw polymer clay, it will also become softer from beating on it, using warming devices or even food processors, and adding thinners if ever necessary. http://answers.yahoo.com/question/index?qid=20120505080320AAJyCe8 (my answer)
As for buying Kato Polyclay, you might just use Donna's shop site and she often has discounts too if you sign up there: http://prairiecraft.com You can also find it online at polymerclayexpress.com and probably other sites. Locally, it's usually carried at Hobby Lobby and some other craft/hobby stores (but not Michaels). Most all polymer clay will be cheaper online (except for the 99 cent sales on Sculpey III), but prices for Kato Polyclay are especially good because it's kind of a one-person venture and the manufacturer VanAken hasn't really put a lot of money behind it.
You might also want to check out the info in my answer here about strategies for doing polymer clay more cheaply, one of which will be to buy online and also perhaps buy the larger bricks of clay rather than the small ones especially for some colors: http://answers.yahoo.com/question/index?qid=20120116075155AAlfxEl This answer has more on mixing your own colors too (...btw, an entire palette of colors can be created from just 5 colors--red, blue, yellow, black, lots of white...plus translucent or one of the metallics for more possibilities): http://answers.yahoo.com/question/index?qid=20120825165031AATl9C0 (Kato concentrates can be good for some things, but would be a lot of work to get all your color from mixing those into white/etc.)
Btw, don't toss out your old Sculpey III or FimoSoft. Those can be mixed with other clays for color or characteristics adjustments, or be baked and used as cores, etc, etc.
You might want also to check out this page at my site for info about the various kinds of "metallic" colors the various brands/lines have (some are mica-based and will do great special effects) since you mentioned a gold: http://glassattic.com/polymer/mica.htm
There's loads more info/tips/lessons/equipment/etc re all aspects of working with polymer clay at my site, GlassAttic. Here's a link to the Table of Contents page there which is really best for finding *where* the topic you're interested in would be located! You can just browse all the way down the page, or you can do Ctrl + F searches for your topic, then use the alphabetical navigation bar to go to the category page you want. http://glassattic.com/polymer/contents.htm ...You might also want to check out the category pages for beads (as well as for jewelry and pendants) and vessels since you mentioned those items. (Note that I haven't maintained the site for several years and lots of links have been broken by their owners, but there's still loads of helpful info/links there.)
P.S. Your Snarky forums look really interesting! Will be checking them out.