Lightweight Hydrocal®* Plaster - 1/2 gal

SKU: C1201



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  • Description

    1/2 gal (1.89 L)

    Net wt. 2 lbs (907g)

    Contents settle.

  • Make Rocks

    Model Realistic Rocks - Tips & Techniques

    Build a Layout Fast and Easy

    Learn how to build a model railroad layout in five easy steps with the revolutionary SubTerrain Lightweight Layout System.

    Tunnels, Retaining Walls and Culverts

    See how to install tunnel portals, retaining walls and culverts on a layout.

    Modeling Rock Formations

    See how to cast rocks to model outcroppings, bluffs, mountains and other rocky formations.

    Earth Colors

    See how to use Earth Color™ Liquid Pigments to color plaster castings, such as rocks, portals, retaining walls and culverts.

  • Made in the USA

    Made In The USA Woodland is committed to a business practice, which supports the economy of our local community.

    We manufacture the vast majority of our products at our Linn Creek, Missouri manufacturing plant, which also houses our product development, package and creative design, marketing, sales and customer service operations.

    Many of the products or parts of the products we manufacture overseas, come back home for packaging and shipping by Woodland employees.

    When you purchase Woodland Quality Brands, you support American manufacturing working in balance with a global economy to support American jobs.

    Safety Warning

    -Model making product. Not a toy! Not suitable for children under 14 years!

    -Produit pour le modélisme. Pas un jouet! Pas adapté aux enfants de moins de 14 ans!

    -Producto para modelismo. No es un juguete! No adecuado para niños menores de 14 años!

    -Modellbauartikel. Kein Spielzeug! Nicht geeigent für Kinder unter 14!


    CAUTION: We do not recommend using Lightweight Hydrocal for body casts as it may irritate skin

    and develop heat sufficient enough to cause burns. Do not take internally.

    MISE EN GARDE: Nous ne recommandons pas d’utiliser ou le Lightweight Hydrocal pour des moulages sur

    le corps car ils peuvent irriter la peau et développent une chaleur suffisante pour causer des

    brûlures. Ne pas ingérer.

    PRECAUCIÓN: No recomendamos el uso de la Lightweight Hydrocal para enyesar ninguna parte del

    cuerpo, ya que pueden irritar la piel y subir la temperatura lo suficiente como para producir

    quemaduras. No ingerir.

    VORSICHT: Wir empfehlen, Lightweight Hydrocal Gips nicht für Gipsabdrücke am Körper zu verwenden,

    da er die Haut reizen und genügend Wärme entwickeln kann, um Verbrennungen zu verursachen. Nicht


    ASTM Certified

    Woodland Quality Brands is committed to manufacturing superior quality, safety-tested products. All of our modeling materials are evaluated by a Consumer Product Safety Commission (CPSC) Approved Toxicologist to ensure they meet the standards for art materials set out by ASTM (American Society for Testing and Materials) International, if applicable. "ASTM International, formerly known as the American Society for Testing and Materials (ASTM), is a globally recognized leader in the development and delivery of international voluntary consensus standards. Today, some 12,000 ASTM standards are used around the world to improve product quality, enhance safety, facilitate market access and trade, and build consumer confidence." For more information about ASTM International, visit

    • What is the best way to make a tunnel?

      Tunnels can be made in a variety of ways.

      Ready Landforms are an easy way to add a tunnel. They are preformed, landscaped and ready to place on a layout. Available in HO and N scales and straight or curved designs.

      Self-supporting Shaper Sheet is another easy way to add a tunnel. Form into tunnel shape and arrange over track. Cover in Shaper Sheet Plaster and add landscape materials. For added realism, paint underside of Shaper Sheet to resemble blasted rock.

      Use 1/4" Foam Sheets or 1/4" Modeling Sheets to make tunnel walls and roof. Use No-News Paper or newspaper to add paper wads around the tunnel foundation to model terrain, and add a double layer of Plaster Cloth to form a hard shell.

      Use the Tunnel Liner Form to mold tunnel sections from Lightweight Hydrocal, Shaper Sheet Plaster or Super Strength Plaster. Connect sections together with Plaster Cloth to form desired length of tunnel.

      Click here to view a video about making a tunnel.

    • What is the mix ratio of Lightweight Hydrocal?

      The mix ratio of Lightweight Hydrocal is 5 parts Hydrocal to 2 parts water (1 1/4 cups Hydrocal to 1/2 cup water).

    • My Lightweight Hydrocal is still wet after 40 minutes. The instructions say that it should be dry by now. What am I doing wrong?

      Different issues can affect the setting and drying time of Lightweight Hydrocal®.

      The amount of water used is critical. Use only the amount indicated in the instructions or the Hydrocal will take much longer to cure and set. If too much water is used, it may never set up completely.

      It is very important to shake the carton of Lightweight Hydrocal upside down for 30 seconds to mix contents thoroughly before measuring.

      Humidity is another factor. Higher humidity can extend dry time to as long as a few days. Placing a fan in the room to circulate air can speed up drying time.

      Hydrocal is a U.S. Gypsum registered trademark.


    • Approximately how many rocks from a Rock Mold will 1/2 gallon of Hydrocal make?

      A 1/2 gallon carton of Lightweight Hydrocal® will yield approximately 14 medium-sized rocks.
      The actual number of rock castings will depend on which Rock Mold is used and how full it is filled. For example, Rock Mold Strata or Classic and a 1/2 gallon of Lightweight Hydrocal will yield 8-10 full-pour rocks.
      Hydrocal® is a U.S. Gypsum registered trademark.

    • Once opened, how long will the plaster products keep? What is the best way to store it?

      When stored properly, plaster products have a very long (years) shelf life as long as they are stored in a way that keeps moisture away from the product.  Put any of our plasters (Hydrocal, Shaper Sheet Plaster, Carving Plaster,  Super Strength Plaster, or Mold-A-Scene) in a sealed plastic bag. Place the sealed bag in a tightly sealed, non-breakable container. This double seal will prevent moisture from interacting with the plaster.

    • Will Lightweight Hydrocal clog a water drain?

      You should not wash any Woodland Scenics plaster product down the drain. This includes Shaper Sheet Plaster, Carving Plaster, Super Strength Plaster, Lightweight Hydrocal Plaster, Mold-A-Scene Plaster, and Smooth-It.

      Plaster residue that remains after applying Plaster Cloth should also be discarded in the trash.

    • My Lightweight Hydrocal will not take the Liquid Pigments in some areas of my terrain?

      Some natural shading should occur when painting your Lightweight Hydrocal surface with Liquid Pigments. However, if the surface is not absorbing pigment and remains white, those areas probably have been contaminated with glue or another substance.

    • Can a Lightweight Hydrocal base be colored with acrylic paint?

      We recommend using our Earth Colors™ Liquid Pigment on Lightweight Hydrocal®* castings. You will want to be sure that there is no glue or other residue on the casting before applying the Pigments, because color may not adhere or may become blotchy.

      *Hydrocal is a U.S. Gypsum registered trademark.

    • Is Scenic Cement used to seal Hydrocal rock castings after painting?

      Yes. Rock castings colored with Earth Colors Liquid Pigments should be sprayed with Scenic Cement. This will seal the pigments onto the castings and reduce fading overtime.

      Click here to view how to seal rock castings.

    • What are the metric mixing measurements for your Lightweight Hydrocal?

      Mix 295 mL of Lightweight Hydrocal with 118 mL of water.

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