One thing to keep in mind is that Hydrocal tends to chip over time. This often results in bright white spots peaking out from your scenery. You can always tint your Hydrocal when you mix it but you'll need to have your tinting medium mixed, measured and ready to pour so the tinting process doesn't cut into your available working time (Hydrocal sets up FAST). Although I've never seen the "gray stuff," it may be dark enough to avoid the dreaded bright white spots in your scenery. Personally, I would prefer a Hydrocal grade with a slower setting time as I always end up with a bunch of hardened Hydrocal in the bottom of my mixing bowl.
Hornblower
I don't know if it's the best, but I used Hydrocal Lite for all my rock castings and they turned out pretty good, IMHO.
I didn't think it was that much help, but yout are welcome.
C'mon people, somebody who knows more chime in.
Dave
Thanks Dave! I appreciate the info!
The club I was in never used anything but the white stuff. The various grades, by my understanding, have different working times. The white is very fast, the grey about twice as long. You could therefor mix a bigger batch, and use it without hardening concerns.
I imagine that different colours/grades will take colour differently, so you don't want to change often, i.e. use up one grade berfore using another supply.
This is not much help, but you are back to the top of the topic list.
Hi everyone! I have a question about hydrocal. I've been to USG website and there are several hobby grade hydrocals available. Which one is the best for scenery, rock castings over foam board?