One of my friends found a bunch of clay in their basement, still sealed, but outside of the original package. However, I am unable to figure out what kind of clay it is. I've checked the EberhardFaber site, but they no longer seem to sell this specific type, or I simply can't recognize it because it's outside of the original package.

Things I've tried:

  • Airdry it, it's sat for a day without looking like it'll harden in the slightest.
  • Bake it for a few minutes on a high temperature, the clay goes runny and melty.
  • Bake it for 15 minutes on a lower temperature, the clay also goes slightly goopy. Does not harden after cooling down again.

Image of the clay

  • Have you noticed the number 8401 on the label?
    – Willeke
    Commented Mar 17, 2018 at 10:47
  • I have, but "Eberhard Faber 8401" gets me no useful results on google. I think the product might have been discontinued or something, or the number is not an actual serial number but a production line stamp.
    – Theik
    Commented Mar 17, 2018 at 10:53
  • I googled in Dutch (one of the languages on the label) and found you this link. If you think it is right, I will convert it into an answer. artsupplyshop.nl/products/boetseerpasta/767825.html
    – Willeke
    Commented Mar 17, 2018 at 10:58
  • It's possible, although my package contains 460G. That one claims it's airdry, which mine seems like it doesn't wan to do, though.
    – Theik
    Commented Mar 17, 2018 at 11:05
  • In that case I am not converting it.
    – Willeke
    Commented Mar 17, 2018 at 11:06

1 Answer 1


This is non-hardening plasteline, also known as plastecine.

For the record, although it is labeled as children’s modeling clay, I do not trust it to be non-toxic. Having worked with exactly this product in the past, I did find it to be great when building seals in damming walls of casting molds. If you want it to be harder, you can cool it / freeze it. This will not harden it, as you are only performing a state change in the oils / paraffins that are used to keep the mass malleable. I would be very cautious of overheating it, as you are likely to generate toxic fumes.

  • Thank you, this explains a lot. I tried just about every trick I could come up with to get it to cure.
    – Theik
    Commented Mar 17, 2018 at 22:58
  • 1
    @Theik - I updated my answer with a bit more information on the product. Commented Mar 21, 2018 at 14:58

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