Cast Versus Gunned Density: Reading Insulating Castable Data Correctly
A cast and a gunned specimen can have different density; compare each value with the installation method on site.
An insulating castable datasheet may publish separate bulk densities for cast and gunned samples. That distinction matters because placement affects compaction, rebound, water addition, and the structure left after drying. A single density figure cannot describe both methods unless the supplier has verified both.
Compare like with like
Record the test temperature and whether the result is for a cast or gunned specimen. A 110°C dry density should not be compared directly with a density measured after firing at a higher temperature. Ask how samples were prepared and whether the proposed nozzle, water rate, and layer thickness resemble the job.
Use density for quantity planning
Convert the lining's net volume to an estimated installed mass using the method-specific density, then allow separately for placement loss. Gunning rebound is a site variable; it should not be hidden inside the material density. Check the as-built thickness after installation because an apparently small thickness difference can change both mass and heat flow.
Royal's custom insulating castable lists cast and gunned values separately. Use the value corresponding to your planned application method.