Don't Forget About Durability

When choosing a finish there are many factors to consider including; color, environmental impact and emissions (V.O.C.'s, NMP, solvents and off-gassing), non-yellowing versus amberizing finishes, availability, application, compatibility, and maintenance. Another big part of the comparison picture is the durability of these finishes and how they will hold up over time. While no one finish type is "better" than another, each will generally have certain characteristics and performance factors that can be measured. Internationally regulated by extremely specific, strict and exact testing procedures, equipment and methods, there are three tests that are commonly done by manufacturers to "measure" the durability of the products they produce. While many, many other factors come into play when creating a finish (such as the products flow and leveling, sheen, ease of use, stain compatibility, dry times and more) durability is a very important aspect. These tests (which again are regulated by international standards, guidelines and procedures) are broken down into three categories, Abrasion Resistance, Scratch Resistance, and Chemical Resistance.

Abrasion Resistance

Abrasion resistance refers to a finish's resistance to what are known as "soft scratches" or scratches that are the result from shoes and dirt or other "soft" substances rubbing and wearing against the finish. For this test multiple sample boards are made of the finish, allowed to fully cure, and weighed individually by an extremely precise scale (measuring out to .0001 grams). Next a specific rubber wheel (similar to that of shoe rubber or a hard eraser) is placed on the sample and goes around a set number of times (generally 1,000 revolutions) at a specific RPM, with a specific weight applied to the wheel (generally 1 kilo). The dust and particulate that wears off the sample board and/or testing wheel are immediately vacuumed away in the closed testing chamber so that they do not interfere with the results. After the test is complete the sample is again weighed and the difference in weight between them denotes how much finish has "worn off". An average is taken of the samples results and a number in milligrams is produced that represents the finishes "abrasion" resistance. For this test lower values indicate better performance while higher numbers show more finish was worn off due to abrasion.

Scratch Resistance

Scratch resistance is a test of the finish's resistance to non-conventional damage. This could be from rocks brought in by shoes, the moving of furniture, pet claws or a multitude of other things. The scratch resistance test is done by using a diamond tip instrument that is drug across the finish sample. Weight is added to the diamond tipped instrument until the finish scratches and the weight is recorded. This means that the higher the number, the better the performance or "scratch resistance" of the finish.

Chemical Resistance

Chemical resistance is the measure of a finishes ability to be unharmed or "resistant" to a wide variety of chemicals. Finished wood samples are made and different chemicals are placed on the samples for varying amounts of time (from 10 seconds to 16 hours depending on the chemical) and the results are measured. The chemicals tested are of a wide variety to simulate spills that might occur on a hardwood floor such as; coffee, wine, acetone, blood, ammonia, and alcohol (both drinking and cleaning types) along with a list of others. The results are then measured based on a visual scale and breakdown into five ratings.

5 - The coating surface is unmodified
4 - In some angles of the light there is slight sheen change but it is not visible in all angles of light
3 - Sheen difference visible in normal light but no discoloration
2 - Visual discoloration spot, white or dark, but the finish is not worn through
1 - Film removed