For the Winter Hill project the Model Railroader staff needed to add rock castings to the scene around the quarry branch. Associate editor Cody Grivno shows you how to make rock castings using molds and a light plaster product called Hydrocal. Cody also provides tips for trimming the castings and applying the finished rocks to the model railroad scenery.
Building the HO scale Winter Hill quarry branch, part 8
By Angela Cotey | February 19, 2013
| Last updated on November 23, 2020
How to make Hydrocal rock castings for model railroad scenery
good work on the rocks Cody now its starting to look like a mine all that is needed is structures and Winter Hill Mine is complete.
rather than using an adhesive to mount the castings, I mix up a "Tooth Paste" slurry , then after wetting the casting back and mount area I press it in place and the squeeze out is used to blend in the castings.
I model military mods and permanent layout. My cars are
Microtrains Army, Navy & Air Force. Any info will be helpful.
Tanks
All of those little pieces that are broken off can be saved and used as "scrim" at the bottom of the cliffs or hills. You may have to break them up a little if they are too big.
I've been using Durobond 45 (from Home Depot) – which is used (usually) for drywalling. It's maybe $8 per 25 lbs – far cheaper than Hydrocal, and works just great.
Also – for mixing – I'm using some flexible 2-cup paint bucket liners I found at Menards. They're also cheap, and flexible – making it easy to clean out the old plaster. Also, when rinsing, I'm dumping the used plaster / water into a bucket, not down the drain.
I had an old Lionel set about 55 years ago. I also set up an HO set with my son about 35 years ago and I can remember using "plaster of Paris". I am now looking at starting all over again but with HO. Your films are a great reminder of the scene work I did a long time ago.
very helpful and informative
I remember this tip from an old Cody's Office
As part of these videos, there's an opportunity to teach other good modeling skills. For instance, when working on scenery, it seems prudent that you'd want to protect already laid and painted track, especially where there are turnouts. In this video, hydrocal castings were laid directly on the rails and you laid the putty knife with adhesive directly on the track, although, thank goodness you had flipped it over so the adhesive was on the top side.
Now someone will likely spend a fair amount of time to clean the rail and ties when a sheet or two of newspaper or lightweight plastic dropcloth over the track could have saved that time.
Thanks for listening.
Cody: Just a note about cleaning up the hydrocal which you didn't show. You really need a bucket or small garbage can, preferably plastic, to wash out your mixing bowl. DON'T was up in a sink as hydrocal will build up and cause a big plumbing bill.
Thanks!
What was thje adhesive used to fasten the molded rock to the layout?
Cody; another suggestion about the Hydrocal cleanup; use a flexible bowl for mixing (MicroMark has them, also a visit to your friendly dentist may help. My dentist GAVE me 2 small bowls he uses for denture moldings). Just let the Hydrocal completely dry, then flex the bowls to get rid of the left overs.
Thanks so much for the sand trick. Much simpler than any of my solutions!
ever think to use a icing bag for the sculpta mold? like icing a cake or adding mortor to brick work?
Amaco Sculptamold is a cellulose-based compound. It is lightweight like papier maché, but it does not shrink. It models and casts like clay, and sets up hard like plaster in about 30 minutes. It is available from DickBlick.com, Amazon.com, etc.
Another good installment – Thanks!
Rookie question… What is Sculpta-Mold exactly, and where can it be purchased? I enquired about this product by this name at Michael's Arts and Craft store and they had no clue what I was asking for.