I am a fan of gypsolite. It dries with a natural light gray tint. I usually squirt in some brown craft store paint to get more of an earth color. I like the gritty surface it dries with. I've never had any clumping issues with gypsolite.
I did have a problem once when my Hydrocal got old, although I always kept it in a sealed plastic container. It wouldn't set in a nice solid casting. Instead, it was weak and fragile. It was simply time to throw it out and get new Hydrocal.
It takes an iron man to play with a toy iron horse.
Thanks to all who provided various ways to proceed. I will try several (break up the lums/shake the bag, more water, vigorous stirring, etc.) on my next use. I expect that, like most things, experience will improve performance, but at least I have some ideas about the directions to go.
Paul.
gmpullmanThey also offer Claycrete. I'd like to try some of this. I don't recall it being mentioned by the model scenery builders. https://www.amaco.com/products/claycrete-1-lb-bag
https://www.amaco.com/products/claycrete-1-lb-bag
I am soooooo tempted to say that about the very, very last thing you'd want is scenicking that dries "exceptionally white when dried at room temperature" ...
Of course it would tint nicely to ranges of brown, gray, or even variegation as desired... just perhaps a little more colorant.
OvermodWhat's the stuff I was thinking was Sculptamold?
Perhaps Gypsolite? I recall old-school plasterers using something like this as a browncoat or scratchcoat under finished plaster. There's also textured gypsum for making "popcorn" ceilings. Vermiculite is a common additive. It used to be asbestos
I recall reading on the Sculptamold bag that they suggest tossing the contents around in the bag in order to re-blend the contents in case any of the binder has settled out.
Here is the very basic American Art Clay* site. (very basic .pdf instructions)
https://www.amaco.com/products/sculptamold-sc-3-3-bag
They also offer Claycrete. I'd like to try some of this. I don't recall it being mentioned by the model scenery builders.
*Manufacturer of Sculptamold.
Good Luck, Ed
You cannot sift Amaco Sculptamold. Do not even try that.
Sculptamold is not for making smooth surfaces, like the name says, it is for sculpting and molding. It is paper mache.
Scupltamold is the best thing ever for blending rock casting together. It is magnificent for forming landscale profiles. I cover it with a thin layer of plaster or drywall joint compound for a final smooth surface.
-Kevin
Living the dream.
BigDaddyI don't think it's a product small enough to sift like flour.
cowmanIt depends on what you are doing and how you do it.
The main things I'll be doing is molds, both rocks and retaining walls/tunnels and using it as a base with cardboard strips and gauze tape. I've used drywall mud for planting rocks and smoothing out surfaces and am happy with it.
Chip
Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.
I'm not sure there is a "better". It depends on what you are doing and how you do it.
I have used Sculptamold in molds and as a filler between castings, also as a coating over smooth foam to give it some texture.Also have used plsater of paris in molds. Little different testure, gives a different look. Experimentation seems to be the best judge of what you are looking for.
Good luck,
Richard
SpaceMouseI use plaster of Parisbut I've heard Sulptamold is better. What makes it better?
For me, it is very lightweight, easy to mix, and dries very hard.
I can't say if it's better than other things, but I like it.
York1 John
I use plaster of Parisbut I've heard Sulptamold is better. What makes it better?
I’ve never had a problem with lumpy Sculptamold. It always mixes to a smooth creamy mixture. I use a Cottage Cheese container to mix Plaster of Paris, Hydrocal, Paper Mache and Sculptamold, keeping the material to a small amount. I never go with larger amount than what a Cottage Cheese container holds. On large areas I do several small batches.I use the same container to scoop the material out of the bag then add water as needed mixing it with a popsicle type stick, adding water until it is to a easily workable state. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
MY sculptamold is packed away for my move. I don't think it's a product small enough to sift like flour. There are stringy bits of paper in it.
Once you apply it, put on your covid gloves, wet them and smooth it out. I never achieved hydrocal type smoothness or level of detail, but it's good enough looking at it from the edge of the layout.
This was a test casting I made:
edit It is partly a plaster product. It could be old stock.
Henry
COB Potomac & Northern
Shenandoah Valley
I scrape it out of the box with a plastic measuring cup. While it had settled together somewhat in the box, scraping it into the measuring cup tended to break it up significantly.
I put it in a small styrofoam disposable bowl and then add water in stages, stirring with a small spatula that I use to apply it. I mix it somewhat on the wet side, thicker than mayonaisse though. It has some lumps but when applied (to plastercloth or plywood) I could then easily spread and smooth it to the extent desired. I did not want it totally smooth as I wanted some texture beneath the later ground foam, etc. I could have made it rather smooth if desired.
I have a spatula set like these that are handy:
https://www.amazon.com/Painting-Stainless-Spatula-Accessories-Painting-Lightwish/dp/B072P1R5B7/ref=sr_1_4_sspa?dchild=1&keywords=small+spatula+hobby&qid=1598565006&sr=8-4-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFGODFVOEZVTDNZWUQmZW5jcnlwdGVkSWQ9QTA1ODIwMDcxU0ExQ1M2V0pOVUhYJmVuY3J5cHRlZEFkSWQ9QTAzODI3MjAzU0QySVgxNTVRMTMwJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==
Have you tried different water amounts to get the consistency that works for you?
Paul
Modeling HO with a transition era UP bent
Since Sculptamold is basically paper mache, just break the lumps apart with your fingers. It also sounds like you need to use more water. Once you apply it, use a flat tool like a butter knife to smooth it.
I don't think you'll be able to sift it unless you're using a very coarse screen.
.
As with baking -- use a sifter when putting the dry product into a mix. There are treatments (some used in the pharmaceutical or herbal-supplement industries) to break up the electrostatic attraction that makes powders clump. In their absence 'cutting in' or beating the mixture with an appropriate power tool for a while will eventually get more even dispersion and hydration... but the texture may be 'wetter' than you prefer.
Fortunately there should be little issue with trapped-air removal, as there is when mixing resin, hardened, and 'colorants' and other additives for casting (the same vacuum technique may help if that is an actual issue, although I highly doubt it even in highly acrylic-hindered plasters with specialty cement or aggregates).
I have just started to use this highly recommended product (Sculptamold) and have a usage question. It comes out of the package in dry lumps, which may be OK for all I know, but when I mix it it stays lumpy even after vigorous stirring. Then when I apply it to a scenery element, I can't get it smooth and I end up with a very lumpy surface (over 1/8" bumps and hollows) which takes a great deal of sanding to get what I want.
I guess I am doing something wrong, and there are probably some usage guidelines somewhere that a newbie like me would find useful. I would appreciate any perspectives that you all take for granted which would help me with this problem.
Thanks,