I have a clay (plasticine) positive of a human figure standing 5' tall

  • Next step is making a rubber mold for the lost wax process and a bronze positive
  • May I use the rubber mold for slip after the wax positive is made, plaster is to fragile and not at all charming
  • Is Raku the answer for drying, if I can make a slip positive
  • Would someone discuss the basics here? Any pointers are welcomed, if they reference the project!
  • The actual mold has multiple pieces that will be joined to form a container into which the slip may be poured and later poured out when the piece reaches the desired thickness.
  • Suggestions on thickness and etc.
  • Ideas other than plaster or slip
  • 1
    Five feet tall?
    – Catija
    Aug 23, 2017 at 1:24
  • @Catija Yes, five feet tall. Will be a complicated mold but, if memory serves me well, it will turn out fine.
    – Ace
    Aug 24, 2017 at 5:01
  • 1
    5 ft tall is well beyond the size for lost wax casting ; 5 in. is more like it. May 2, 2021 at 19:54

1 Answer 1


Making a piece out of ceramics, you should use plaster for the mold as it draws out the moisture from the clay slip, and you will not need to wait a long time to get the thickness of your clay. If you use a rubber mold, the moisture has to leave the clay through the air, which is very slow.

Raku is a way to fire the clay, so unless you want a hardened piece out of the clay, I would not fire it raku style or otherwise.

If you are wanting to make a bronze piece, why use the ceramic as part? You can make the finished piece in several parts of bronze or clay. The pieces can be combined afterward; molded clay glued with slip, or welding or soldering the bronze.

Another way would be a breakable mold for the entire piece, where you break the complete work out of the mold in one piece.

  • 1
    I tried to clean up the grammar and punctuation but I'm not sure this is accurate for what you want to say. Please review the edit and modify anything where I didn't get it right.
    – fixer1234
    Dec 3, 2020 at 6:22

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