Abrasive options for cleaning and surface prep beyond sandblasting
Four professionals from around the United States share their favorite blasting materials and tools for the Sep/Oct 2021 issue of inPAINT magazine for professional painting contractors.
One of the four is Ryan Thomas, Field Operations Supervisor for Painters USA and NACE (now AMPP) Certified Level 1 Coatings Inspector.
Following are some key points contributed by Ryan, with a link to the full article (PDF) at the end of this page.
Priorities and challenges
- Keeping dust to a minimum.
- Working on sensitive surfaces like brick.
- Removing a significant number of mils (one thousandth of an inch) in a short turnaround time.
As Ryan states in the article, “Our crews have to move fast to create the proper surface profile for the spec of that project.”
What is Abrasive blasting?
Abrasive blasting uses pressurized air or water to propel abrasive media against a surface to remove old coatings, corrosion, or other forms of contamination. It is also commonly referred to as sandblasting or grit blasting.
How and when is abrasive blasting used?
Abrasive blasting is used in a variety of ways, even the lettering and engraving on most modern cemetery monuments. For commercial and industrial applications, abrasive blasting is used for a number of different requirements:
- Prepare surfaces for new paints or other coatings.
- Remove rust, scale, and other contaminants.
- Make a rough surface smooth.
- Make a smooth surface rough.
- Shape a surface, like edge profiling for machined components.
- Create a matte or textured finish.
Dry blasting vs. wet blasting
As you might guess, dry blasting uses only air to propel the abrasive material, wet blasting mixes the dry abrasive with water, either before or as it leaves the blast nozzle. Each has benefits and disadvantages:
Dry blasting pros and cons
- Dry blasting is efficient, versatile, and cost-effective. It has lower equipment and preparation requirements and is suitable for a wide range of surfaces and applications.
The bad side of dry blasting is that it releases fine, abrasive airborne particles, which can be a respiratory hazard as well as a static explosion risk. These can be mitigated through use of PPE, exclusion zones, encapsulation / containment, equipment shutdowns, and other tactics.
Wet blasting pros and cons
- Wet blasting reduces dust and requires less abrasive material because it creates more mass at the impact point. Wet blasting also leaves a nice feathered edge when a new coating needs to be interfaced with a sound, existing coating. It also reduces static because the sparks are "cold" which reduces explosion risk.
As for disadvantages, wet blasting consumes water, an increasingly valuable resource. Costs can be higher due to additional process requirements. Metal surfaces must be quickly and sufficiently air dried afterward as they are prone to flash rusting. Finally, wet abrasive waste is heavier and more difficult to remove.
PDF link to entire article: Four pros share abrasive picks for successful prep
Meanwhile, if you’re looking for a fast, effective, versatile solution for cleaning or refining surfaces in your commercial or industrial facility, remember Painters USA. We’re happy to answer any questions regarding the use of abrasive blasting for your needs.
Abrasive blasting services from Painters USA