When I am working with polymer clay, I don't generally have a lot of problems with my clay being too soft. When I first started playing with it, though, I often used Sculpey III which is definitely good for beginners, but my goodness is it soft. After a few years, I moved on to a firmer clay - Premo. Premo certainly isn't as hard as Kato or Fimo Classic, but it is more firm that Sculpey III and Fimo Soft.
But I sometimes find that Premo can be soft, as well, and it makes it very difficult to work on three dimensional objects that require a lot of detail and layering. As you work on one side and hold onto the other, details tend to get squished... and the overall piece just looks dreadful.
So when does Premo seem the softest? Well, when it's super fresh, that's for sure.
I just opened a brand new 1lb package of Silver Premo this morning, and the softness was the equivilent to Sculpey III. And after kneading it, it was just a mess. When you're having this many problems with a newly bought package of Premo, it is almost always because it is fresh, fresh, fresh.
How can you avoid this, exactly?
You've got many options, actually. If you use a lot of polymer clay, it is a good habit to keep track of how many un-opened colours you have, how many open colours you have, as well as which colours you use the most of. After awhile, you start to get the knack of it, but sometimes it helps to write it down. If you can practice this habit, you'll never run out of clay. Why? Because you know exactly how much of what colour you have, and you can go out and grab some more of the colour you'll need far before you'll actually need to use it. Call it Polymer Clay Forecasting, if you will.
So how does this Polymer Clay Forecasting come in handy? By purchasing your clay ahead of time, you can "age" it for as long as you need. I find that leaving packages of polymer clay in a cool dark place for a month or two is sufficient enough to really make the clay less soft - so I always make sure to buy ahead of time.
Heat can be a factor as well, so your clay may be softer in the Summer months. If you can, try purchasing your clay in the cooler months, and if you have hot hands, try keeping them cool by dipping them in cool water once in awhile or by holding an icepack for a minute. Try to keep a cool work surface. I purchased a marble/granite slab at the kitchen store on sale, and it keeps a nice temperature all year round. If your work surface is too warm, try sticking it in the freezer when you aren't using it or by sticking a cold gel back beneath it as you work on the surface.
But if you're in a pinch, and you don't know what else to do, this is where Leaching comes in handy. If I have a big pack of really soft Premo, and I have none of that colour left in other packages, then I will leach the entire package of clay.
What is leaching, exactly? Well, it's a process in which you can remove some of the plasticizers, which make the clay soft, from the clay. This can be done with a white piece of paper and a pasta machine.
First, take your soft piece of clay and form it into a flat mass. Take a piece of white paper (just so you don't get any ink colour onto your clay) and fold it in half like a card. Between the two halves, place the clay inside, and then fold it closed again. Put it through your pasta machine at the thickest setting, and then go to the next smallest setting. Keep doing this until the clay is about 1mm thick - either setting #4 or #5. Now you've got yourself a clay-paper sandwich!
Take the clay-paper sandwich and put it on top of a hard cover book. And then pile a bunch of heavy books on top. Alternatively, you could sandwich the paper between two books and just sit on it if you like. In about 10-15 minutes, remove the books and grab the clay-paper sandwich. Peel the paper from the clay - you'll notice a weird oily residue on the paper, kind of like grease. This is the plasticizers!
Upon kneading the clay in your hands, you'll notice that it is a lot more firm. But if it isn't to your liking, though, you could always leave the clay between the white paper for a little bit longer. But just remember - too much leaching can lead to very crumbly clay, and you'll notice that it is a lot more fragile after baking. I've never had to leach my Premo for more than 20 minutes, and it's been a good bet so far. Some folks leave it overnight, or for several hours. You'll have to experiment to see what works for you!
If the clay sticks to the white paper, you can easily scrape it off with a razorblade. If you do not have white paper, try using a brown paper bag or cerealbox cardboard - as long as it has no print or ink on it, it will work fine.
Have any findings on this topic? Let me (and everyone else who is reading) know by leaving a comment. :) Happy claying!