Hammer paint (or hammered paint) is a special

lacquer Lacquer is a type of hard and usually shiny coating or finish applied to materials such as wood or metal. It is most often made from resin extracted from trees and waxes and has been in use since antiquity. Asian lacquerware, which may be ca ...

with a surface that looks like hammered metal when dried. It is also known as hammertone.

Composition

The slightly

iridescent Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, butterfl ...

areas are caused by the different orientation of very small shiny particles, which are suspended in the lacquer. These particles are often made of the mineral

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...

. Mica is resilient, reflective, refractive, dielectric, chemically inert, insulating, lightweight, and hydrophilic.Dolley, Thomas P. (2008
"Mica"
() in ''USGS 2008 Minerals Yearbook''. Alternatively,

aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...

bronze Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals, such as phosphorus, or metalloids such ...

powder may be used. To make the "hammered" effect more pronounced, a small amount of

silicone oil A silicone oil is any liquid polymerized siloxane with organic side chains. The most important member is polydimethylsiloxane. These polymers are of commercial interest because of their relatively high thermal stability, lubricating, and Liquid di ...

may be added directly before application.

Purposes

Hammer paint is often used to beautify technical apparatus or as a protective coating. The optical advantage of hammer paint is that surfaces look acceptable even if the underlying surface is not flat and smooth. To get a regular paint to look smooth, the surface would have to be prepared first, for example, by

spackling In the United States and various other countries, spackling paste or spackle is a putty used to fill holes, small cracks, and other minor surface defects in wood, drywall, and plaster. Typically, spackling is composed of gypsum plaster from ...

sanding upright=1.35, Sheets of sandpaper with different grit sizes (40 (coarse), 80, 150, 240, 600 (fine)). Sandpaper and glasspaper are names used for a type of coated abrasive that consists of sheets of paper or cloth with abrasive material glued to ...

grinding Grind is the cross-sectional shape of a blade. Grind, grinds, or grinding may also refer to: Grinding action * Grinding (abrasive cutting), a method of crafting * Grinding (dance), suggestive club dancing * Grinding (video gaming), repetitive and ...

polishing Polishing is the process of creating a smooth and shiny surface by rubbing it or by applying a chemical treatment, leaving a clean surface with a significant specular reflection (still limited by the index of refraction of the material accordin ...

. With hammer paint, this step can be omitted. Some hammer paints (e.g. by

Hammerite Hammerite is a brand of hammer paint made by Hammerite Products, a subsidiary of AkzoNobel. Company history Hammerite paint was first developed in 1962 by Allen Forster and later manufactured at the Finnigan's factory in Prudhoe, Northumber ...

) are formulated to be usable directly on rusted steel without surface preparation other than brushing to remove the loose rust. Beyond that, the mica improves the durability and color of the paint job."Mica"
. The mica reduces aging by protecting the underlying binders from

UV radiation Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...

. The mica also makes hammer paint relatively hard and scratch-resistant.

References

Paints {{chemistry-stub