Imagine the world’s greatest builder attempting to build a hospital on a crumbling, uneven foundation. Even if his work is done to the best of his ability, the overall result will be a product that was doomed from the start. The idea that the foundation of any project is crucial applies across all fields, especially painting super structures and commercial properties. Surface preparation, preparing the surface prior to coating, is vital to the success of a industrial or commercial painting project, because no matter how well the coating is applied, if paint is coated over an inadequate foundation the results could be failure.
Contrary to what one might think, a smooth surface is not ideal for coating. A rough surface, however, one not unlike the surface of sandpaper is ideal, as it will be much more difficult for the coating to come off of the coarse surface. When steel surfaces are prepared to be coarse like this, is it called surface profile. Although the surface should be rough, it should not be dirty. Much like trying to place tape over a dusty surface, the dust will reduce the contact between the tape and the surface and the result is no adhesion.
This same scenario applies to coating as well, and a clean surface will allow the coating to stick better. In the world of coating, this “dirt” can also come in the form of chemical contaminates which will prevent sound adhesion. Chemicals that will interfere with the coating’s contact with the surface are known as non visible contaminants. The worst kind of non visible contamination is arguably soluble salt contamination, which can absorb moisture and damage the attachment and even the steel underneath. Unfortunately, simple dry abrasive blasting or power washing is not enough to rid a surface of these types of contaminants. A soulable salt remover such as hold tight is one of the best ways to remove this invisible bond breaker.
Other factors to be considered would be the environment of the surface being coated and the type of coating being used. If a surface is in an extreme environment, (heat, cold or constant contact with water) much more preparation may be needed. On the other hand, all that may be needed in terms of surface preparation is an old fashioned hand tool scraping and hand wiping. In most cases the surface should be at a minimum, power washed to remove dust and dirt and then hand or power tool scraped to remove loose and peeling paint. On our industrial painting projects our workers typically power tool clean or sandblast before coating.
As with anything, cost is of course also a factor. Cleaning to SSPC-SP 3 power tool clean, or SSPC-SP 2 hand tool clean, can be roughly 5 times cheaper than SSPC-SP 5 media blasting to white metal. These code numbers, established by the Society for Protective Coatings, can also include SSPC-SP 7 brush-off blast, SSPC-SP6 commercial blast and SSPC-SP10 near white metal.
It is important that the coating applicator or painting contractor is aware of the vital importance of surface preparation. Just as the greatest builder cannot perform to his full capabilities on a poor foundation, the most expensive coating applied perfectly will be doomed from the start.
If you’d like more information on the importance of surface preparation or the coating process, or would like a commercial or industrial painting service completed, contact your local contractor. Readers on the east coast near NJ, NY, CT or PA can reach out to Alpine Painting and Sandblasting online at AlpinePainting.com or by phone at 866-596-0349.
By Dave Scaturro, Sales Director for Alpine Painting.
Credit to: Barnhart, Robert, Debbie Mericle, Chuck Mobley, Tom Hocking, Jeff Bogran, and Ernestine McDaniel . "Why Surface Preparation is Important ." Paint Square . May 2013: n. page. Web. 23 Aug. 2013. <http://www.paintsquare.com/archive/?fuseaction=view&articleid=4974>