Frequently Asked Questions
Of necessity, forge linings must be able to withstand extremely high temperatures. Because of this constraint, things like cinderblocks, most kinds of masonry brick, stone, and plaster are all poor choices for forge linings.
Instead, line your forge with refractory brick rated to 2300 degrees Fahrenheit or more. Alternatively, use a rigidized ceramic wool blanket coated with castable refractory. Check out some tried-and-true forge builds for inspiration.