That would have been me. The completely clear rigid plastic IKEA “Krus” containers work perfectly for Kato: after 14+ months there isn’t even the slightest marking on them from raw Kato sitting directly on the plastic.

I agree that they do not work for Premo unless you use some kind of safe lining: there was enough of a reaction when in direct contact for there to be noticeable cloudiness under the Premo sample on a test piece after several weeks. By now, more than a year later, the Premo sample is partially stuck to the test plastic, and where it’s not stuck the surface of the test plastic underneath where the Premo was is roughened and looks frosted.

And they definitely do not work for Fimo without lining! With Fimo there was a consistency change even in the very short term; then, after several weeks the Fimo had basically become melded with my test piece, and now, more than a year later, it looks like it’s submerging itself in the clear plastic and will eventually eat its way through!

I don’t like the semi-transparent plastic boxes or containers myself because you can’t see through them well enough, and they don’t transmit sufficient light when they’re stacked either. So for Premo and Fimo, I just line my completely clear “Krus” containers with a single layer of Glad Wrap: that’s sufficient to protect them without losing the ability to see everything inside with perfect clarity. (Kato, of course, doesn’t need even that and goes straight in.)

So… test for polymer clay compatibility if you can, and if in doubt use a safe lining like Glad Wrap, or use a more generally safe plastic if you don’t mind your containers not being completely clear.

Thanks.

Love your videos.

Nancy

Please store unpacked material wrapped in aluminium foil, in tins or plastic bags (PE / PP). Please avoid unhardened FIMO coming into contact with polystyrene (PS), PVC or Styrofoam, since the surface may undergo a chemical change – as described in your mail.

7 weeks after I posted the initial 3-day test, things are now as follows:

- The Kato still shows no reaction with the container at all. The clay is just as it was, and there are no marks or residue visible on the container.

- The Premo has now left a definite frosted-looking mark on the container where it’s been sitting. It’s not stuck, and the consistency of the clay still seems pretty normal, but there’s definitely a reaction.

- And the Fimo has basically become part of the container. Yuck!

I have also had problems with putting 2 pieces of Fimo cane in a plastic bag together and them sticking to each other – pulling parts off when I tried to separate them. I guess I should get some UK Glad Wrap equivalent to avoid that in future and probably use a blade to separate them instead of just pulling – would have cuased less damage.