Surface preparation is the foundation of any successful coating system. Among the most critical factors in ensuring adhesion and long-term coating performance is the surface profile, often referred to as anchor pattern or roughness.
For professionals working in blasting, coating inspection, corrosion control, and protective painting, accurately assessing surface roughness is not just best practice, it’s a requirement under many industry standards. That’s where ISO Surface Roughness Comparators play an essential role.
What Are ISO Surface Roughness Comparators?
ISO surface roughness comparators are non-electronic inspection tools used to determine the profile of abrasive blast-cleaned steel surfaces. These comparators conform to ISO 8503-1 and ISO 8503-2, international standards that define both the comparator design and how profile grading should be performed.
Key Features:
- Constructed from corrosion-resistant metal.
- Feature four reference surface profile grades on each disk.
- Designed for grit-blasted (G) or shot-blasted (S) surfaces.
- Allow profile evaluation by visual or tactile comparison.
- Ideal for field use, especially where electronic gauges are restricted (e.g., hazardous areas).
Why Use Surface Roughness Comparators?
Surface profile plays a critical role in how a coating adheres to a substrate. If the profile is:
-
Too smooth: coating adhesion can fail, leading to premature peeling or corrosion
-
Too rough: excessive coating thickness may be required, increasing material costs and trapping air or moisture
Using ISO surface comparators ensures you maintain consistency, reliability, and compliance with inspection standards in industrial coating workflows.
Industries that Rely on Profile Comparators
- Oil and Gas (onshore/offshore pipelines, tanks, rigs).
- Shipbuilding and Marine (hulls, decks, ballast tanks).
- Infrastructure (bridges, towers, steel structures).
- Heavy Industry and Manufacturing (machinery, components).
- Energy & Utilities (power plants, wind towers).
- Rail & Transportation.
How to use a Surface Comparator
1. Clean the surface to remove dust or abrasive residue.
2. Select the appropriate comparator type:
- Type S (Shot): for surfaces prepared using shot abrasive.
- Type G (Grit): for surfaces prepared using grit abrasive.
3. Place the surface comparator directly against the blasted steel.
4. Visually compare or feel the surface using:
- Visual: Direct visual comparison, optionally using a 5x magnifier for better clarity.
- Tactile: Using the back of a fingernail or a wooden stylus to feel the texture and compare (as allowed by standard).
5. Determine the grade:
- Finer than Fine
- Fine
- Medium
- Coarse
- Coarser than Coarse
6. Document the result and repeat at multiple areas to ensure consistency.
Note: This method is fast and efficient but provides qualitative (not numerical) results. For quantitative analysis, other tools like replica tape or digital surface profile gauges may be used in combination.
Surface Profile Comparator – Result Classification
When using a surface profile comparator, the results are qualitative, not numerical. The blasted surface is compared against reference segments on the comparator and classified into one of five roughness grades:
Finer-than-Fine
→ The surface is smoother than segment 1 (the finest grade on the comparator).
Fine
→ The surface matches segment 1 up to, but not including, segment 2.
Medium
→ The surface matches segment 2 up to, but not including, segment 3.
Coarse
→ The surface matches segment 3 up to, but not including, segment 4.
Coarser-than-Coarse
→ The surface is rougher than segment 4 (the coarsest grade on the comparator).
Benefits of Using ISO Surface Roughness Comparators
- Portable and rugged – no batteries, no electronics.
- Instant feedback – assess in seconds.
- Cost-effective – especially for high-volume inspection work.
- Standards-compliant – meets ISO 8503 for global project requirements.
- Safe for hazardous zones – no risk of sparks or interference.
Surface Roughness Comparator Distributor in Singapore
LFC PTE LTD is the authorized distributor of DeFelsko Surface Comparator in Singapore. Our expert team can assist you in selecting the appropriate solutions for your needs.
Stay informed about DeFelsko products and other leading industrial inspection tools by following LFC PTE LTD on social media. You can find us on Facebook, Instagram, YouTube, and LinkedIn.
