i bought them from a local craft store - they are by 'rayher'. don't know what they're made of but they are hard - much like baked pc.
I'm trying to remember exactly why you said in your original mention the molds "didn't work." These did work from looking at your results though these particular molds don't seem to be very sharply defined
ones, and they're also not as deep
as one would like for making the thinner/less-deep shapes.
Compare those with these I made (mostly from clay):http://www.craftster.org/forum/index.php?topic=101292.msg960710#msg960710
And these by better-known companies:http://smartpickins.com/pat/pmzoo.jpghttp://www.google.com/images?q=push+mold
i just tried slicing off the result - but they got squished and were very thick. and the details in the rose leaf edge were lost.
If you want only the molded item without any surrounding clay, start with a smaller clay ball of clay (often a teardrop shape) than would fill up the whole mold cavity. That way when you remove it, there will be no flange or excess clay to remove.
You can remove it by pressing another wad of clay to the back side of the clay in the mold, or use BlueTac, and some other ways, but you may need to use a release for certain brands of clay or if they are too soft (or just cool in the mold before removing).
If you do have excess clay, you can press it to the back side of the molded clay if there's only a little, or you can trim it off with the edge of a long blade (flexible one works best) or even using the tip of a blade or a needle tool of some kind if it's first been pressed down to a non-porous surface to hold it in place while you do the trimming.
Mold shapes with freestanding thin parts are tricky to do in a freestanding way (like the bud with the stem) unless they're made with background clay, bas relief style. The entire background clay can be trimmed to an interesting shape though with a cutter or a flexible blade, etc.
And some people do techniques where they "shave off" the upper dimensional areas from molded shapes (like they do for some mokume gane techniques, etc) in order to place them in other places. Here Sarajane Helm shows how to do something like that one-handed:http://polyclay.com/decoratedeggs.htm
It looks like you may have some cracks in your molded clay too, which can be caused by the clay not being conditioned long enough to be supple/pliable (so needing more heat, working/kneading, and/or oily additive).
i tried a thin sheet of clay but they were too fragile. and for the rose you need a good piece of clay to fill out all the petals....
Did you mean that the raw
clay was too fragile, or the baked result was too fragile (which would happen if you were using a brittle clay like "Sculpey")?
If you ever did want to make a "hollow" mold, you could press in a sheet of clay, then press something in behind it that was removable (after removing from mold or after baking), but you'd want to use a strong brand of clay for that. Or you might be able to do it with a firmer raw clay, and cooling the clay in the mold and/or using a release. Doing that for the rose mold would be even trickier though because it's a more difficult mold to begin with, and has lots of small cavities needing to be filled completely.
The softer clays just don't work as well for molds, but should be fine if you handle them right. And often I don't use a release at all (or I use cornstarch, or water for all but the Fimo and Cernit lines) just because I've learned how to press it and kind of rock out without getting things stuck in most molds.
i had thought i would be able to make quick and easy flower/leaf embellishments for my little figures..
They should be quick and easy, though some of the shapes can be a little more fiddly than others till you figure out how to do them.
no i didn't try liquid clay.
Neither solid polymer clay nor liquid polymer clay can be left in molds during baking since they'll bond**. They can both be left in silicone molds though--ones you buy or ones you make.
**it's possible that using the Kato Repel Gel (or a superglue solvent, cycanoacrylate debonder, from hobby store) or even ArmorAll (silicone--if you never want to use a paint/finish/anything on that surface later, or stick other clay or anything to it) would allow that to happen but there isn't definitive info for using them for that purpose.
Don't forget that making your own molds can create great ones too, whether you're using little items and textures from around the house or making your own items to create molds from.
You might want to read around on my Molds page for more details about all these things, and more:http://www.glassattic.com/polymer/molds.htm
...especially the General Info.
category and the Releases
And this page has more on trimming or cutting with a needle-type tool, etc:http://www.glassattic.com/polymer/cutters-blades.htm
...look under Freehand Cutting