Detecting Defects in Surfaces and Surface Preparation

abrasive blasting

Detecting Defects in Surfaces and Surface Preparation

Updated: March 25, 2021

Defects in metal, such as sharp edges and welds, are a primary cause of coating failures. To avoid rework, loss of productivity and poor results, it’s crucial to identify surface defects before blast preparation of metal and steel substrates.

The following takes a look at how to detect defects in surfaces. It also gives insight into effective methods of surface prep.

Know What You’re Looking For

There are three primary categories of defects to look out for when you’re working with metal surfaces. The first is imperfections resulting from the welding process, such as spatters, slags, ripples, undercut, porosity and end craters. The second is edges, including rolled edges and thermally cut edges as well as defects caused during fabrication by punching, drilling, sawing and shearing. Last are steel surfaces in general, such as pits and craters, groves and gouges, indentations, roll marks and other imperfections.

Inspection as Part of Your Surface Prep for Sandblasting Routine

Before blasting for surface preparation, the abrasive blaster has the responsibility of inspecting the materials to detect defects. In addition to a visual scan for cuts, scoring and other indicators, it’s necessary to touch the surface with a gloved hand to feel for indentations and protrusions.


There’s a grading system to take into account when you’re detecting surface defects. This system will help you determine the level of preparation you’ll need to reach and whether blasting or significant grinding and re-edging will be required. Sometimes, there will be two different grades for each side of the material depending on how it’s going to be used. The classifications are as follows:

  • P1 Light Preparation
  • P2 Thorough Preparation
  • P3 Very Thorough Preparation

Shot Blasting Industrial Surface Preparation

Detecting defects in surfaces before painting and coating is only half the battle. The next step is to perform abrasive blasting to eliminate imperfections and deliver a surface in line with its preparation grade. An efficient, economical way of doing so is with shot-blasting, which offers a faster process than many other methods, a smoother surface and the greater ability to customize finishes.

Blasting is not only useful in blending away defects and smoothing out rough spots but also for cleaning contaminants and achieving a textured final looking. Industries that utilize abrasive blasting range from manufacturing, automotive and construction to industrial painting and coating, electronics and steel and mining.

Getting Help With Steel Surface Preparation

If you’re looking for assistance with identifying defects and surface preparation, the experts at Finishing Systems are here to help. Since 1972, we’ve worked with some of the world’s most iconic manufacturers to improve their products and streamline their operations. As a leader in the finishing industry, we offer abrasive blasting and a variety of other products and specialized services for companies small and large across the nation.

Learn more about our full capabilities by visiting our Job Shop & Services page. For additional information on identifying defects in steel surfaces — and to speak with a live customer representative — contact us online or give us a call today.