Rob Spangler mentioned he used drywall mud for his stream bed. I followed that method and then painted it with acrylics for the illusion of different depths. That work very well. No hydrocal needed.
Rio Grande. The Action Road - Focus 1977-1983
Before you try to put your mixed hydrocal down WET the stream bed with water so it is wet. Then add your mixed hydracal to the stream bed.
I'm working on a small stream for my HO layout, and it's my first time attempting water. I have some Envirotex Lite for the resin. This is on extruded foam board. Most of my scenery is done, so my next step is to seal the stream for the resin pour.
I attempted using WS lightweight Hydrocal this week, but I had opened the container last summer (2019). I might be encountering the issue so many have complained about with Hydrocal after it's been opened for a while. I can run my finger across the stream, and white powder covers my finger. If I attempt to add some paint, the "rock" falls apart.
Since it should be dry by now, is it likely the Hydrocal is no longer usable? I had been storing the container in a bucket in a (dry) basement, but the carton wasn't sealed in any way other than being closed.
If I need to toss it, is there a good way to clean it out of the stream bed? Maybe if I sprayed some water on it I could scoop it out?
A friend had suggested using WS Flex Paste as a sealant. I tried the Hydrocal first since I already had it, but I think I'll try the paste if I'm able to successfully clean out the Hydrocal.