Hello Stephen
'This is easy to fix, as I am sure you have found out, casting problems can often be a combination if smaller issues that collect together to create a failure
Simply reduce the powder water ratio to 38/100 for R&R ultravest and Let it bench sit for 4 hrs before starting the burnout and mix for 4-5 minutes, these steps should solve the problem
Other things to check
make sure the temperature of the slurry is 72F
Use deonized water if possible
Make sure the burnout is not too fast
Use RR investment
best of luck
Geofffey Pyle
Arttech Casting CO
800-418-9970