Preparing steel to paint it is fundamental. What’s usually needed? Steel sandblasting. This is the most important step before painting steel. The correct preparation process allows the paint to stay longer and do its job well. So, follow proper steel preparation before applying paint. Besides, you wouldn’t want the paint coating to fail, would you?
If you leave even a tiny grease on the steel’s surface, it can reduce and impair the adhesion of paint to the substrate. The same is true for oxides, oil, and other harmful components.
Sulfates, chlorides, and other chemical contaminants are not visible to the naked eye. But, they can absorb moisture through coating systems. As you can guess, it could lead to premature failure.
Here in this article, we’ll learn how to prepare metallic surfaces using commercial sandblasting. We’ll also tackle other blasting methods for corrosion protective coatings.
Steel preparation before painting
A wide selection of non-metallic and metallic abrasives can remove rust. Some of which produce better and faster results than others. Aside from the type of abrasive, the abrasive size is also considered in a commercial sandblast service. This factor affects the efficacy of cleaning the metallic surface.
In general, fine grades are effective at cleaning new metal works. But, coarse grades may be required for corrosion-prone surfaces. So, determine whether you need a fine or coarse grade abrasive.
Meanwhile, a rust remover with a fine grade abrasive on pitted steel is more effective. It is because it can enter the pitted region easier compared to bigger particles. You may need a variety of grades to disintegrate, remove mill scale, and cleanse pitted areas. It will depend on the metallic surface’s condition.
Here’s a breakdown of the steps mentioned earlier:
- Step 1 – Light sandblasting cleaning
- Step 2 – In-depth sandblasting cleaning
- Step 3 – Rigorous sandblast cleaning
- Step 4 – Sandblasting to clean the steel’s surface
Sandblasting or abrasive blast cleaning
Also called shot blasting, sandblasting utilizes an abrasive medium to clean rusted and mill-scale surfaces. It involves the continuous contact of abrasive particles at a fast rate on the metallic surface to clean it mechanically. The most popular approach is to do it in a jet stream of water or air.
As a result, the surface treatment specification should specify the needed surface roughness. Usually, it indicates the average profile that the blast cleaning achieved.
The steelwork should also remain in good condition after the surface preparation. It is especially true that re-rusting, also known as “gingering,” often happens in damp areas. To prevent this from happening, store the steel in a dry environment. Otherwise, apply the substrate as soon as possible.
It is best to use soda blasting to restore steelwork. This process is more delicate than others, making it ideal for masonry restoration. It is sometimes used for varnish and paint stripping, too. You can also use it to clean the boat hull.
Here’s a fun fact for you. Soda blasting is also used for dental cleaning! It is also the solution used by the sandblasting company hired to clean the Statue of Liberty in the 1980s.
Hand and power tool cleaning
When preparing steel, hands and power tools are sometimes necessary. For example, you can use wire brushes or scrapers to clean slight stains and rust on the metallic surface.
You’ll require power tools for mill-scale and worst areas affected by rust. Some jobs cannot be done manually – unless you have the entire day to spend cleaning the steel surface. But, power tools are not recommended to prepare new steelwork.
Sweep blasting or light sandblasting
Are you looking for an effective industrial sandblast service? If so, sweep blasting might be the one for you.
In this type of sandblasting, a non-metallic, fine grade abrasive is applied at low pressure to clean steel. While this process can be highly effective, only an expert can achieve a good result. It is also best to use this method on flat surfaces as using it for complex shapes can leave other areas under or over-prepared.
To sum things up, how you prepare steel before painting determines the result and its performance. Whether it’s for a small or big industrial project, steel preparation should be done carefully and properly to avoid loss. And so, the blasting method and the way the job is done are both important.