Greetings. I am having problems making a scenery shell (not making rock molds) using hydrocal. It 'calcifies' in the process. It may be old, but has been stored in a bucket in a climate controlled basement. I may be making too big of a batch at one time. I mix it with water, and then dip strips of paper towels in it for the shell.
I'm basically ready to throw out what is left and get something else. What are better alternatives? Or what am I doing wrong? I have purchased hydrocal in the past and did not have this problem.
Thx!
Hi
Mark B. here. I used to own AIM Products and used Hydrocal as well as US Gypsum Casting plaster for our products. So I have some experience with this stuff. Sometimes the plaster just gets "old" and it's set-up time is greatly reduced. Even though you stored it in an air tight bucket, for some reason it does not retain it's normal cure time. Try using smaller batches with the plaster you have and work quickly. Once this stuff starts to set, it's game over. I read where some people used vinegar as a retardant, but I wonder how long it would take for the vinegar smell to go away. Weeks, months...? Old plaster,even if properly stored starts to get a gritty feel to it. If your dry plaster has that feel, it may be over the hill. Sometimes it's a matter of how long it sat at the dealer's store also. Our local dealer had a slow turnover of his inventory and you never knew what you were going to get. I found a dealer 180 miles away and would make the trip to buy his as they were turning a pallet of it every two weeks. It should feel smooth like powdered sugar.
For my own layout I used Sculptamold. It's sort of a plaster/paper mache combination. I get a decent working time and you can re-wet it to furher extend it.
Hope this helps,
Mark B.
I have some old hydrocal and it works fine' I use a paint pot or pail' always add the hydrocal to the water and if it old makes it slighty thinner than pancake batter. 5min is about it then its hard' so make small batches
I had 20 year old stuff and it worked fine. The temp of the mix etc can affect the set.
I assume that you can't water down sculptamold in such a way to dip paper towels into, correct?
iawestern I assume that you can't water down sculptamold in such a way to dip paper towels into, correct?
I never tried but I think your hunch is correct -- it is not a semi-liquid slurry type texture.
Dave Nelson
I have used hydrocal off and on for years and the supply I have now is easily over six years old and still performing fine. And yes, it sets up quickly but I have found that if I keep applying it with a brush as it begins to set, I can get some pretty natural looking rock outcrop areas.
Sculptamold is more like paper mache than a thin slurry you can dip paper towels into. But to be honest, I gave up doing the paper towel thing quite a long time ago in favor of plaster cloth.
However, being rather old school, I do still tend to make my mountain and hills frames out of cardboard strips rather than foam. In fact, if I ever decided to put a camera on my locomotive, the insides of my tunnels would largely be a trip down breakfast cereal memory lane where we would view cut up boxes of Trix, Wheaties, Corn Chex, etc.
I have used Hydrocal to build my entire layout. I have keep the same 100lb bag for many years. Here is the way to go.
1. Put a gallon container of water in the Freezer. Use this for your mixing water.
2. Also use vinegar in the mix. Have never detected any smell as it will be painted
3. Use Small batches. Will set quicker as it gets older
4.When your cleaning up the leftover use the hard small pieces for boulder and small rocks
Hopes this helps
Harold
While not familiar with hydrocal, as a possible alternative, could you use Plaster of Paris?
I have used vinegar as a setting retardant. My layout did smell like salad, but only for a couple of days. I think that was for Durham's Water Putty, which I use for asphalt roads.
I have had hydrocal go bad. I keep it in its jar, tightly sealed, but one time it wouldn't set properly and the castings crumpled. I bought a new jar and cured that problem.
For a scenery base, I like Gypsolite. It gives me a course surface that I like for landscape. I plan and use rock castings. The Woodland Scenics castings are generally fine. For foreground scenes, Bragdon foam with their molds give excellent results. They're more labor intensive, but very light and when done they put hydrocal to shame. I have some rock wall castings from Dave Frary, now another company, that have found a home on my layout.
It takes an iron man to play with a toy iron horse.
I use Woodland Scenics plaster cloth. It's a lot less messier than plaster and it's easy to apply over cardboard strips. On top of that, I use Sculptamold, that can be applied for either a fairly smooth or lumpy appearance. The only time I will use plaster is when I need to make a street. For that, I use Polyfilla. It's expensive, but used in small quantities, the cost is not that bad. It becomes quite hard when dry.
I use plaster of Paris for rock molds. Using cold water will delay the setting time.
Simon
I am someone who can imagine hills and such from the bottom up so I use beadboard foam to build my scenery. (If worse comes, I can get the stuff for free from work. It is usually put for recycling otherwise. In a sense, I'm recycling it as well.) I glue it together with construction adhesive. I let it cure and then use Scluptamold to cover the structure.
I like Scluptamold as you don't have to be exact with the mix. If it's a little wetter, it tends to last a bit longer. I use plastic silverware to apply and finish it.