Mixing plaster

Discussion in 'N / Z Scale Model Trains' started by cpNscale, Jun 28, 2004.

  1. cpNscale

    cpNscale Member

    What is a good ratio for hydrocol/plaster to water?
    The directions on the Woodlans Seanics tends to thicken with in minutes making it near inpossable to spread with a brush.I usally have to apply it with my hands which is very messy.
  2. davidmbedard

    davidmbedard Member

    I thought you just mixed until you got 'pancake' batter. I believe the thicker you make it, the quicker it sets.

    If I am making a rock mold, I would use more hdrocal and less water.

    If I am dipping in paper towels to make a shell for a mountain, Id use less hydrocal and more water.

    Off Topic....

    How much Hydrocal are you going to need? There should be a supplier of it in your area (I dont know where that is) who will sell you HUGE bags of it for pennies on the dollar compared to Woodland scenics.......


  3. cpNscale

    cpNscale Member

    I'm going to need a fair bit but will mix it up in only 1-2 cup plaster amounts at a time so i can work with it.
    I live in Edmonton Alberta.
  4. belg

    belg Member

    Also when you mix it, use ice cold water and a little vinegar this will give a longer setup time.
  5. Jodam

    Jodam Member

    My father was a tradesman Plasterer, he told me years ago that the set speed can be, sped up or slowed down. Using milk & Salt. the problem is i can't remember which is for what. He's now 78 and past remembering.
    I'll do a test when i get to laying my scenery. i remember using it in the '70, on our first layout a HO set up.
    Hope this helps.
  6. davidmbedard

    davidmbedard Member

    Edmonton eh? Im from Calgary..........

    Here in Calgary I go to WINROCK? I dont know if that is how you spell it.......
    They have huge bags for about 80-100 bucks.....the equivelent of about 30 or so cartons of Woodlands stuff.

    Check it out.

  7. cpNscale

    cpNscale Member

    Am i looking for hydrocal or plaster at a building supply store?
  8. davidmbedard

    davidmbedard Member

  9. cpNscale

    cpNscale Member

  10. Clerk

    Clerk Active Member

    What is the difference between Hydrocal and Plaster of Paris????
  11. davidmbedard

    davidmbedard Member

    Yup....thats the stuff.......Alot cheaper than woodland scenics...
  12. ts1trains

    ts1trains New Member

    What's the light weight hydrocal that woodland scenics sells?

  13. belg

    belg Member

    I believe the difference is the density of the material when it sets up . I don't know if it is made from the same thing and is just a different mix like the difference between 3000 lbs concrete and 5000lbs
  14. RailRon

    RailRon Active Member

    Salt (it's inorganic) speeds up the setting time. Years ago I made some experiments, and I don't recommend using it. If you use too much, the dried plaster tends to crack, and if you use not enough there is no apparent reaction. There's no use to bother with it.

    Vinegar and milk (both are organic!) slow down the setting time. Again take care with the amount: Too much of the stuff and the plaster doesn't set at all. :mad:

    Like David I would suggest to vary the setting time by mixing more or less water with the plaster/Hydrocal powder. Pancake batter consistency is a good rule-of-thumb :thumb: for covering larger areas; for rock or masonry wall castings mix it stiffer, like mud in a drying-out puddle.

    Once you have really started covering your layout with a landscape shell, handling this messy stuff can become outright funny! :confused: :rolleyes: :rolleyes: :D :D :D
    Just be sure to cover the floor with newspapers - and don't wear your best clothes for that occasion. ;) :eek: :eek: :eek:

  15. davidmbedard

    davidmbedard Member

    AH...the MESSY hand problem...Make a thin solution and dip paper towels in the the mix (carefully...and use brawny towels). Then lay the papertowels on the layout (do atleast 2 layers....expecially if you are going to lay the towels over crumpled news paper and such). It makes life easy. And I would suggest adding some green food (or brown) coloring to the mix as itll take an extra step out of the landscaping process (you wont need to paint it). When the plaster is wet, sprinkle on ground foam....most of it will stick......

    Thats all I can offer for now. If you want to get into painting locomotives and such....let me know.

  16. Clerk

    Clerk Active Member

    Thanks Belg. I have been using Plaster of Paris as I haven't been able to fine any hydrocal in my area. I get plaster of paris at Osha.
  17. cpNscale

    cpNscale Member

    One last question,do you add the powder to the water or the water to powder?
  18. jmarksbery

    jmarksbery Active Member

    add the powder to the water :)
  19. davidmbedard

    davidmbedard Member


    Either way.....
  20. Fred_M

    Fred_M Guest

    I add water to the powder, LOL Fred

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