Thursday, 7 January 2010

Conditioning Polymer Clay

This is a first - a blog post without pictures! I have been playing with polymer clay, but not nearly as much as I'd like to, and I haven't finished anything off to a standard that I'm happy to show off yet!

The problem with polymer clay is that you have to condition it before you can play with it. Clay is properly conditioned when you can fold a thin sheet in half and have no cracking at the fold.

Different brands of polymer clay have different properties, and as I have learnt this week, until you understand what they are, you won't necessarily be successful in preparing the clay for play.

I worked with Fimo Classic last summer, and found it a bit of a pain to condition, even using a pasta machine, so a friend suggested I try Fimo Soft. Fimo Soft is easier to condition, but I don't like the look or feel of the baked clay as much as baked Classic.

I worked with Sculpey's new lightweight Polymer Clay - it is a dream to condition as it is very soft and easy to knead. It also takes colour very well after baking - using alcohol inks and Johnson's Klear/Future acrylic floor polish. If I had found this first, I probably wouldn't have tried any other polymer clays! Except that I like to use black clay, and I haven't seen this product in any colour other than white - it may exist, but I haven't seen it.

I had read that Kato Clay is harder to condition, but worth the extra effort in terms of the finished product. I have tried it this week, and would agree completely that the finished product is the best I've tried, but the conditioning nearly defeated me.

I asked around for suggestions about conditioning polymer clay. Friends suggested that I place the pack of clay in my underwear or that I sit on the package for a while to warm it up before trying to condition it in a pasta machine. I have discovered that this works well - but only for some clays.

Fimo clay is conditioned by the use of gentle warmth and kneading, or running the slightly warmed clay through a pasta machine. So the underwear or sitting on it technique works well.

Kato Clay is conditioned by pressure, so warmth doesn't help at all. And even in thin slices, running it through my pasta machine just resulted in a load of crumbs which I couldn't get to stick together enough to run through the machine again, and which were too hard to knead. I spent an evening trying to get crumbs through the machine in enough quantity to stick together. It was really hard to get through the machine, and I had to run it through between 35 and 4o times to get it manageable, but it still wasn't properly conditioned. I gave up and left it alone for a couple of days.

And then I had a brainwave. I remembered reading that you can use your Wizard to condition polymer clay, so ran some clay through it, between plastic bags. The clay got softer, but the bags stretched and popped. I ran some more through between pieces of teflon craft sheet. The clay got softer, but I managed to split the craft sheet! After running the clay through the Wizard about 10 times it seemed much softer, but also seemed to be getting 'dry', so I moved it to the pasta machine and ran it through a few times. It was really easy to run through the pasta machine, and working it between metal seemed to make it less dry and more plastic and elastic.

So, I now have my perfect method for conditioning KatoClay - run small amounts through the Wizard ten times, then through the pasta machine 10 times. Combine the resulting small sheets into bigger sheets, until all the clay you want to work with is in one sheet, and can be folded without any cracking at the fold. This method is much easier than the pasta machine alone, and certainly much much quicker.

I need to experiment with what I use to protect the Wizard plates whilst running the polyclay through the Wizard - polythene is too stretchy, teflon craft sheet is not stretchy enough, and probably too thin. Ideally, 2 thin metal plates would be best, but until I can think of how to create those (cutting up the Christmas 'Quality Street' tins?), I will try using the thin plastic used for slot-together files & boxes, or acetate from Christmas Card packaging, or transparencies. I'll edit this post and let you know what works best when I have tried a few things out!


  1. A 'Wizard' is a die cutting machine, made by Spellbinders. It exerts huge pressure and the ratchett handle makes it easy to squeeze things through between the plates. I hardly ever use it ot die cut, but use it with Cuttlebug folders to texturise cardstock & metal, and now use i to condition polymer clay.

  2. Thanks for sharing all your hard work. Have you tried alfoil (aluminium foil) or is that a dumb suggestion lol.

  3. I was wondering the same thing, I read on the Kato website, it is best to slice the clay out then use your hand roller to get it worked out somewhat, then when you run it thur the pasta machine it will not crumble, I plan to try that next time, might be a great upper arm workout ;-)




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