selector wrote:Fred, were you thinking of gypsolite or sculptamold?
Could be very wrong, but I think both (gyposlite and sculptamold) are essentially the same thing.
Fred
That does help, and it sounds more and more, that hydrocal, is nothing more than a brand name for lime plaster ( lime ) - as opposed to plaster of paris ( gypsom ).
If this is correct, I don't understand why people don't just by a bag of slaked lime, and make there own lime plaster - for $10-$15 or so will get you a #50 bag that will make alot of scenery.
In a nut shell, slaked lime is mixed with water, and cast or spread, and then CO2 in the air combine with the calicium hydroxide to make limestone - that's why it's so hard, it has turned back into limestone.
I would bet that Woodland Scenics light weight hyrdocal is slaked lime mixed with a lightweight filler such as pearlite.
Hydrocal is a special form of plaster. It is much stronger than conventional plaster (Plaster of Paris), and can be cast with fine details better than P of P. It sets quite quickly (15-30 minutes), and can be expensive when repackaged for sale in hobby shops. Hydrocal was heralded as a breakthrough in scenery construction in the '60s, when it was used for "hard shell" construction. The big plus of Hydrocal was that paper towels (dryer sheets, etc) dipped in Hydrocal could be laid over temporary forms of wadded newspaper and masking tape. The wadded newspaper could be removed after the plaster was dry, and the Hydrocal shell would be self-supporting. This was considered much faster and easier and usually lighter than P of P and screen wire techniques. My layouts build in the '70s used window screen and P of P because I couldn't locate and/or afford Hydrocal.
With the arrival of foam layouts, the weight of plaster coats for carving scenery details negates the initial weight advantage of foam. Structolite (there is a similar competitor whose name escapes me) is a type of plaster with a lightweight filler added. The filler creates texture, as well as lightening the plaster. Structolite does not work well for making plaster castings because the filler prevents the details from transferring to the plaster.
Hope this answers the question.
Fred W
Bear "It's all about having fun."
ARTHILL wrote:You did not mention premixed dry wall mud and that is really different and in my mind all I use except for molding rocks.
Didn't mention it, since I used to deal with it when I worked in the remodeling bussiness many yrs ago. What I don't know is what hydrocal and stucolite are, and how they compare to plaster.
When I first built a ''mountain'' I used the old ''paper towel and plaster'' method....Jeez what a mess!!!! and even though I used blue shop towels it still wasn't as strong as I wanted.
Fast forward to phase II of my layout....I looked at hydrocal, plaster and paper mache....none were what I really wanted....and they all cost more than I was ready to part with.....I've used premixed drywall compound on several jobs and knew how it set up and how strong it was....so I got a 5 gal. bucket and experimented with it......I won't use anything else now.
It's so much stronger and less messy than the other stuff and 5 gal. goes a long way. You can sculpt it and carve it and sand it, and it's easy to paint. I usually mix some latex paint in the mud to make it easier to paint and not have white showing through.
At $10 a bucket you won't lose much if you don't like it.....give it a try, you might find it's exactly what you were looking for.
The difference is the strength and hardness when dry. Hydrocal is very dense, hard and strong. If you are doing scenery any of them can be used.
Dave H.
Dave H. Painted side goes up. My website : wnbranch.com
Structolyte, plaster and hydrocal what is the differance between them?
Sounds like they are all used the same way ( and could very well the be same stuff for all I know ).