Stone & Slab – Applied Finishes

An important aspect of working with natural stone has to do with surface textures and finishes.

This includes dimensional stone tile, 2cm & 3cm slab as well as natural and cast stone surfaces. It is a fact that not all materials are available with the desired architectural surface finish right from the manufacturer and the Andrusko Group is well versed in how to create the perfect material texture for your next project.

It takes some know-how along with the right techniques to properly work surfaces. Often these surfaces are needed to address public safety concerns as walking surfaces, matching of materials during restoration or there may be particular aesthetic considerations that are desired for the surface finish.

Most of the techniques and tools are are also able to be deployed to the job site to work the stone in addition to being a studio-based activity.

3cm Granite slabs ready for shipment. Thermal finished for a restoration project in Boise, Idaho

The Andrusko Group studio has mastered a number of techniques to meet nearly any surface finish need. These include:

Thermal Finishes can be applied to many (but, not all) materials which will react against the surface of the stone in a relatively controllable way. The application of extreme heat produces a beautiful, spalled surface texture that appears in many cases as if it is completely natural. Under the right, controlled conditions this technique can be applied successfully to many 2cm & 3cm full slabs that can then be cut down to the proper size.

Sand-blast Textures can be achieved both wet and dry – Sandblasting will produce a unique textured surface in some ways similar to thermal finishes. There are a number of techniques that can vary the texture from media size to using wet blasting techniques. This approach can produce a nice finish on tiles and thinner materials that can’t handle the thermal approach. This technique can also work well on materials that won’t spall properly in the thermal process.

Rotary Abrasive techniques can work to produce a variety of finishes. This generally utilizes an electric or pneumatic tool that rotates with some kind of abrasive material. There are quite a few options in this category including sand paper, electroplated scarification drums, rotary bush hammer plates and diamond disks of varying sorts. Generally this technique will produce a fair amount of vibration and can damage some thinner materials if used aggressively.

Bush-hammering can be performed in a variety of ways using hand-tools, electrical devices and pneumatic tools. This technique is generally very aggressive and can cause damage to thinner or fracture prone materials but has a broad range of finishes and textures and is an excellent approach under the right conditions.

Polishing/Honing can be done with hand-tools and large flat areas can be worked with a specialized tool known as a rotary arm polisher. The Andrusko group has a large collection of hand-held polishing tools and a modest-sized rotary arm polishing station.

Chemical Etching can sometimes be an option for certain materials. As a general rule, the Andrusko Group doesn’t utilize chemical etching other than with dilute muriatic acids in a controlled setting. Muriatic acid is a very common masonry cleaning solution that will react with the calcium carbonate – the primary constituent mineral in many marble stones – to break down the mineral. It can be used for etching or removing the polished surface and will quickly create a natural, weathered finish.