Hydrocal

[Anonymous]

Hi ,

Just back in the hobby after a 20 year absence, and I have forgotten much about using the hard shell scenery. My specific question 's deal with tinting and retarding the setting of the plaster. Can any one point the way?

Thanks

[cacole]

I have heard that vinegar retards the setting of plaster, but haven't tried it. Acrylic or latex paint accelerates setting. Rit clothing die can be used as a tint, or you can paint it after it has dried with any type of diluted paint.

Instead of Hydrocal, I prefer 20 Minute Casting Plaster, which can sometimes be found at the larger building supply stores such as Home Depot or Lowe's; unfortunately, it only comes in a 120 pound bag so you would need to see if they will just let you have some from a broken bag or chip in with another modeler who needs plaster and share the cost.

[selector]

I have tried the vinegar, and was glad of it after my first disastrous attempt to use plaster to line my river bed and lake. I just used acrylic paint to tint my plaster, but with vinegar to offset any reaction toward quicker set-up. You only need a tablespoon of vinegar at most.

Hydrocal is a pain to mix; plaster of paris is much quicker, and takes longer to set up (so you can demure, change your mind, and fiddle around for about twice as long). And....AND....it's way cheaper. See your local Walley World.

[bogp40]

If your having a problem with the working time, hydrocal is the wrong choice for that aspect of the project. For the hardshell try using veneering plaster(blue board) or plaster of paris. Save the hydrocal for you rock molds etc. Hydrocal will work for the soaked paper towels though, due to the mix being very loose like milk.
For coloring plaster try using masonry dyes. They are dry powder that you add to the dry plaster- color of the dry mix is slightly lighter than the mixed and cured. I generally don't waste the dyes on the first or second coats- use the colored plaster for the last coat.
Rock castings dye the hydrocal mix in water until loose and creamy, you don't have much working time, so make all the pours and clean up the tools. Many times I will place rock molds just when the hydrocal is flexable. Mix small fresh batch of plaster to use as glue butter up the mold and plop on the desired location. You may have to hold it in place for a few minutes- you feel it getting warm then let go. Leave the mold on at least 1to 1 1/2 hour before peeling back. Remember to wash/ scrub out the mold or it could be damaged for future use.
Bob K.

[howmus]

Hi wjlang,

For hardshell scenery, I use joint compound in 1 gal. tubs. It takes quite a while to set but is easier to work with than hydrocal, plaster of Paris, and some other casting plasters. I dilute it with water to the consistancy of pancake batter, then dip the paper towels in it and apply to the scenery. Later I brush more of the diluted compound onto the hardshell with a paint bru***o build up a thicker and stronger hardshell base. After it drys it can be painted or (the old way) zip textured as you wish.

[Anonymous]

You must have missed Joe Fugate's FORUM CLINIC: Building realistic scenery

[wp8thsub]

Lately I've been using liberal quantities of sandy soil in the plaster. It gives a nice texture to finished rock faces and gives me half again as much working time. The formula is not critical, but for rockwork batches it's about one part water, one and a half to two plaster, and one dirt. For other finishing work (plain ground aside from rockwork) I use one part each.

While the dirt doesn't dimini***he plaster's strength much, if at all, adding sufficient dry tempera color to avoid noticing chips can really make the plaster weak. Powdered coloring intended for masonry seems a better bet.

[snowey]

QUOTE: Originally posted by howmus

Hi wjlang,

For hardshell scenery, I use joint compound in 1 gal. tubs. It takes quite a while to set but is easier to work with than hydrocal, plaster of Paris, and some other casting plasters. I dilute it with water to the consistancy of pancake batter, then dip the paper towels in it and apply to the scenery. Later I brush more of the diluted compound onto the hardshell with a paint bru***o build up a thicker and stronger hardshell base. After it drys it can be painted or (the old way) zip textured as you wish.

ZIP TEXTURING?? THIS IS 2005, NOT 1971![D][:D][:D][swg][swg]