So I’ve began experimenting with the lightweight hydrocal making rocks and stuff. I decided to make a display setting for my train using the rocks I casted, it all worked out rather well and looks real good. I did run into a bit of a situation though, when cementing the rocks to the wall (plaster cloth) I would run into issues getting the cement used up before it set, so to get by this I would add more water to the cement to loosen up a bit in order to finish off the job. Well being new to this whole thing I realize now I probably shouldn’t have done this as the ratio would now be altered. As a result some of the areas of my rock face are nice and hard were other areas are still soft after a few hours. I’m wondering if anyone has had experience with this and knows wether or not the seems will eventually harden so that I can paint them or am I stuck having to start over? Any help/advise would be greatly appreciated.
Lex,
I cast my rocks using Plaster of Paris. I use ‘plaster wrap’ as well and leave a vertical ‘wall’ where the large rock section will be. I spray the ‘wall’ wit hwater and then use a 90 minute drywall mix applied as a ‘batter’. The rocks are them trimed and pushed into the wet drywall mix as it sets up’ I fill in the voids with more of the drywall mix. The 90 minute working time really helps. I use ‘Sheetrock’ brand with a 90 minute working time. You can also get 20, 45, 60, & 120 minute working times. It comes in 18 lb bags and most home improvement store should have it. I bought mine at a Menards store. I usually ‘stain’ my rocks with watered down acrylic craft paints from Hobby Lobby or Walmart. Creamcote & Apple Barrel brands are very inexpensive and they have great flat colors of greys and ‘trail tan’ that I use for limestone/sandstone rockwork.
Jim Bernier
Jim, Thanks for those tips, I like the idea of the extended work period. Not to mention the cost savings.