The World of Plaster

Discussion in 'FAQs' started by jimnrose, Aug 2, 2002.

  1. jimnrose

    jimnrose Member

    I finally started the scenery phase of my layout layout out cardboard strips but tried phite plaster & paper towels. The paper towels weren't strong enough to retain any shape between the strips (3" spread) and the white plaster takes forever to cure. Sooo, I'm off to get paper shopping bags, but need help with finding the right type of hydrocal. Literature says use 'lightweight hydorcal. When I pull up ASG home page they offer at least nine different products. The closest seems to be 'White Hydrocal'. Can anyone help out. The supplier is far off and I need a large quantity so I'm trying to shorten my learning curve. Thanks, Jim
  2. shamus

    shamus Registered Member

    Hi Jim,
    I don't use hydrocal, never have, always used a product that can be bought at any builders supply, it's called "BLUE HAWK Undercoat plaster"


  3. jimnrose

    jimnrose Member

    Shamus, thanks for youur input. I read a few articles on the subject and concluded that I should use construction paper instead of paper towels and White Hydorcal, so I'm off to the building supply house. I undeddrstand Hydorcal B11 is better but it's not available. Also understand I can retard the curing time by adding baking soda. Another article said the Hydrocal should be added to the water and not the inverse.
    This phase of the project is most challenging for me. I have no experience forming rocks and replicating natore with the contours and colors is quite a reach for me.
    Take care, Jim
  4. t. alexander

    t. alexander Member

    Jim, In the past I've used the gas station type paper towels, "nicked a bunch" ;) and the grocery store type paper sacks. I even used an old cut up bed sheet. To help support the cardboad you can stuff wadded up newspaper behind it till the plaster dries.

    The easiest way to make rocks and out-croppings is with a mold. I make my molds from real rocks and chucks of coal, using stuff called SilPutty.
    I use styrofoam instead of hollow shell now and just add the rocks to it.

  5. alkcnw

    alkcnw Member

    Hey Jim, I've benn using the plaster soaked gause bandage. You can get it from either your drug store or Woodland Scenics. It works reak well to give a solid base for the hydrocal or plaster!:eek:
  6. Vic

    Vic Active Member


    Hi Jim, "Doctor Hydrocal" is here to the rescue:D :D I've used that stuff for 30 years or better. I keep 50-100#'s of it around all the time.

    Plain old white Hydrocal is all that you need. For the paper towels use those coarse brown ones like you find in service stations or rest rooms. The brown paper grocery bags is what I use. Just cut them up to the size needed.

    Stuff some wadded up newspaper under the carboard strips to support the strips while they dry then just pull the newspaper out after the strips are dry. Then mix up some more Hydrocal and paint it on with a paint brush...use a cheap one 'cause it will ruin it.

    You are going to find that Hydrocal sets very fast. Add a table spoon of white vinegar to the mix to retard it.

    I've real good luck in finding Hydrocal at ceramic supply dealers. Among other things its used to make ceramic molds. I've heard of "lightweight" Hydrocal but have never seen it or used it. It must be "cut" with something as regular is very dense.

    Hope this helps:)
  7. 60103

    60103 Pooh Bah

    something that is not mentioned very often is that the hydrocal and paper towel (industrial grade) is the base for your scenery. The regular plaster is added over that (zip texturing and such). Reason is that hydrocal doesn't take paint and stains very well.
    can you confirm that hydrocal turns into alabaster when it sets?
  8. Gary Pfeil

    Gary Pfeil Active Member

    Something not mentioned yet and a very old technique, is to use window screen instead of the cardboard strips to support the plaster. This is what I used in the 60's, I later tried the cardboard but didn't care for it. My current layout doesn't have mountains, just some hills and a few cliffs, I am sculpting insulation foam for the hills, probably will use plaster for the cliffs when I get to them.

  9. Vic

    Vic Active Member

    Hi David, Sometimes I wish that it would turn into something:D Best I can get it to do is turn in to a mild form of concrete. :eek: :D :D It's some hard stuff if you get it on too thick

    You are right about it not taking paint well. Seems like it just "drinks" any kind of solvent type paint. I found that those acrylic craft paints like you get at the Wal-Mart work well with it. I think its because they are water based. For large areas I just thin some down with water and just flow it on with an ordinary paint brush. India Ink mixed with alcohol and sprayed on with a spray bottle also works well for adding shadows to rocks outcropings.
  10. Matt Probst

    Matt Probst Member

    Jim: As far as your base scenery goes, some guys have recommended putting wadded up newspapers under the cardboard, but I tape sheets of newspaper on top of the cardboard so I can better visualise what the final scenery contours will look like before I mix the plaster. If I don't like what I see, then changes to the cardboard web are easy to make so I don't waste any plaster. And , yes, plaster should always be mixed into the water. White vinegar added to it also slows the setting time.

    I get my hydrocal from a hobby shop that stocks 50 lb. bags of it. I believe the manufacturer is U.S. Gypsum Co. You may be able to get some ordered in from a home improvement center or check your yellow pages under "plaster dealers, wholesalers".

    Hope this helps some! Let us know how you make out!

    Matt--Hershey, Pa.:)
  11. Vic

    Vic Active Member

    More On Hard Shell

    Hi Guys, When it got down to it I never really liked the paper towels dipped in plaster. That was just too time consuming and too messy. Since most of my scenery is going to be mountianous I sorta "changed the rules" on the hard shell scenery just a bit.

    First of all I use cardboard strips cut from old boxes. I make the strips 1/2 to 3/4 " wide. I then make a "lattice" out of them for the area to be covered. The strips are fastened to the backdrop and together using a hot glue gun. Use those cheap craft glue sticks they are fine for don't need wood working grade.

    Then I take brown paper grocery bags and slit them open...discard the bottom. Cut some pieces large enough to cover the area of the strips and then "crumple" them up real good. Then spread them back out and you've got the texture for a mountain side. If a smoother terrian is needed just keep smoothing the crumpled bags back out until the desired texture is obtained. Then fasten the bag paper to the strips using the hot glue gun. You don't have to get it fasten everywhere just "tack" it down so it stays in place.

    Next mix up your plaster as we've already discussed and just paint it on with an ordinary paint brush....2" is a good size. I like to add a second coat for strength once the first one is dry. Then proceed to paint the terrain or cover it as desired.

    Here's a pic that sorta illustrates the "steps" Ground cover and scenery hasn't been added yet.

    Attached Files:

  12. Gary Pfeil

    Gary Pfeil Active Member

    That's a good idea Vic, much easier and neater than the dipping method and way cheaper than the gauze.

  13. jimnrose

    jimnrose Member

    Hi Guys,
    thanks for all the inputs. I started yesterday and found that baking soda (didn't know about vnigar till now) was a must. Instead of paper bags I got a roll (500sf; $10) of building paper and cut the strips about 9" wide. Found I needed wooden straps (luckily had a bunch) to hold up the cardboard strips until the hydrocal cured. I've got a long way to go (350sf or so) and like Vic's idea of securing the paper to the strips and applying the hydrocal with a brush. I'll try this next. As everyone says the time consuming job is cleaning the tools between batches.
    I'm guessing that the first stage is building the shell & concentrate on the terrain. The second stage will be to add the color to the hydrocal and define the details (rocks, portals, hills, streams, waterfalls etc.) After the shell coat wouldn't it be easier to switch to plaster for the finish coats. Plaster could be prepared in larger batches, takes paint & stain better while the hydorcal provied the strength for the shell?
    Well, I'm off to mix a few batches. Take care, Jim
  14. sumpter250

    sumpter250 multiscale modelbuilder

    I have had great success using "gutter screen", expanded aluminum screening used to keep leaves out of the rain gutters. When it is formed to shape, it retains that shape even under the weight of the Woodland Scenics "plaster cloth". Prior to using Plaster cloth, I would cut newsprint into 1" wide strips about 2" long, and soak these in 50/50 water/white glue, and lay them over the gutter screen. When this had dried, I would "paint"on the plaster. Two or three coats as needed.
    Because I was building modules, the scenery had to be strong, and lightweight. This method seems to be the best for that purpose, fifteen years of transporting, and no damage yet.
  15. jimnrose

    jimnrose Member

    I'm back again; check in time. Adding vinegar seemed to accelerate the cure time so I went back to baking soda and have plenty of time to paste the mix onto premounted paper. I really like Vic's idea of hot-glueing crumpled paper onto the cardboard strips and using a brush to apply the paste. It allow me to cut the paper around portals and curves as well as verifying the profiles before applying the paste. The clean-up between batches is faster without having a pan (paint roller type) to pre-soak the paper. Take care, Jim
  16. Screen Sounds Good

    Gary, I like the idea of using screen, how wide do you cut the strips??
  17. 60103

    60103 Pooh Bah

    Usually when using screen you don't use strips. Cut a piece big enough to cover the whole area and then push it up and down to the shape needed. Usually support underneath with scrap wood and such.
    Watch out for sharp wires, especially on recycled rusty metal screen. Anyone know which screen works today with the various plastic and aluminum and ??? types?
  18. pcentral

    pcentral Member

    Another method of making mountains is using heavy duty tin foil crumpled up and then spread out across the mountain to be. This gives you some texture right away. Then cover it with your plaster and paper towels. I used this method on several layouts including a temporary Xmas layout, until I found out about geodesic foam mountains. Now I can't imagine building mountains any other way.
  19. Vic

    Vic Active Member

    Like a famous chef once said ...."I love to cook but I hate to clean up the mess":D

    Cleaning up after using plaster is always a chore. If you have ever noticed professional plaster's tools are made out of stainless steel so the plaster doesn't stick to them. That's why they can get cleaned up in a hurry.

    A great source for tools for using with plaster are these "Dollar Stores" where they sell every thing for $1.00 per item. Raid their kitchenware department.:D and their hardware department. :D There's a wealth of stuff there that can be used for scenery making:) Mixing bowls, spatulas, paint brushes, scrapers and etc. and the good thing about it is that its so cheap that you don't have to worry about messing it up. If it gets "too bad" just throw it away and use another one. I bought a few "plastering supplies" at one yesterday.... A bag of 6 plastic mixing bowls, 2 rubber spatulas and 4 2" paintbrushes. The spatulas and brushes were two for a dollar! Total costs...$5.00:) :D Don't think that I'd want to cook or paint my house with any of this stuff but its gonna be just fine for plaster and what don't clean up gets thrown away!!!:) :D :D
  20. billk

    billk Active Member

    Re: Hydrocal

    Just a guess, but Woodland $cenic$ sells something they call "Lightweight Hydrocal".

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