Thick. Thermal coloring of copper alloy is different from physical spraying coloring. The colored color looks as rich and natural as it comes out, but the weight of the metal itself cannot be reduced. The disadvantage of thermal coloring of copper alloy is its massiness. Copper alloy thermal coloring, also known as bronze chemical thermal coloring, uses heating as a catalyst to promote the chemical reaction between compounds and bronze surface, naturally produces various colors, and achieves the effect of decorating bronze surface.