Stone flaming

Stone flaming or thermaling is the application of high temperature to the surface of stone to make it look like natural weathering.^[1][2] The sudden application of a torch to the surface of stone causes the surface layer to expand and flake off, exposing rough stone.

Manually flaming the surface of a stone slab

Flaming works well on granite, because granite is made up of minerals with differing heat expansion rates.

Process

Machine flaming the surface of a stone slab

After removing a rock from a quarry, the rock is sliced into multiple flat slabs using a diamond gang saw. The saw leaves flat surfaces with circular marks. Flaming is done by wetting, and then running an oxygen-acetylene or oxygen-propane torch over the surface. As shown in both pictures, the torch is usually held at a 45-degree angle to the stone, so that released glowing sand grains are blown away in a harmless direction.

Alternatives

Alternative techniques for creating a rough surface on sawed stone include:

• bush hammering
• sandblasting
• hydrofinishing

See also

Flame treatment