Molds and Plaster Castings

Discussion in 'Finishing Techniques' started by eTraxx, Jul 26, 2011.

  1. eTraxx
    eTraxx Active Member
    @SLK posted his results with using 3d printed parts to create molds and resin casts. That prompted me to post up my own results. I also used prints to make RTV molds and then those molds to cast plaster copies

    The model is of a Coke Oven face in 1:48. It consists of two columns and a large and small arch. The base is a piece of Sintra (PVC foam board) .. everything is glued together with epoxy.
    [​IMG]

    I made a mold box and epoxied the model to it ..
    [​IMG]

    I used Smooth On's 'oomoo 25' RTV. The only thing I would do different would be to use a brush to make sure the RTV was pushed into every crevice. Just pouring on did get 'almost' into every detail. One of the plaster castings in in the lower left
    [​IMG]

    Close up of the cast piece
    [​IMG]

    This is a test-piece I used to experiment with coloring. Since the brick in a coke oven like this would have been hard used, grimy etc. .. I sprayed some AI (Alcohol India Ink ) wash on, let that dry and then dry-brushed some FolkArt Terra Cotta acrylic
    [​IMG]

     
  2. lensman
    lensman Well-Known Member
    Very impressive. Could I ask what brand of plaster you used or does that make a big difference?

    Glenn
     
  3. eTraxx
    eTraxx Active Member
    Plaster is something I picked up at Hobby Lobby . something called "Pottery Plaster - for use in ceramics" .. it's harder then plaster of paris at least. If I had a choice would use Hydro-Cal .. but that's a pain to get my hands on.
     
  4. lensman
    lensman Well-Known Member
    Thanks. This is something I'd really like to try but I have no specific reason to order a large model and then make a mold from it - in other words I can't justify the cost to satisfy my own curiosity :)

    Glenn
     
  5. eTraxx
    eTraxx Active Member
    Glenn,
    This is one oven in a bank of 16 for my On30 module. In reality, there would have been hundreds.

    [​IMG]

    The 'brick work' inserted through the face of the structure and starting to add Sculpy 'stone' facing.

    [​IMG]

    Still early in the process

    [​IMG]

    This was my first time to use RTV. Went pretty well I think. The various 'bits' were ordered prior to the jump in cost for FUD along with some others so it wasn't that bad.
     
  6. lensman
    lensman Well-Known Member
    Holy c**p that is one impressive project... and I can see why you'd want to mold them rather than have them all 3D printed !