Steel Ringlock / Layher-Type Structure Powder Coating Process

When people look at a finished black Ringlock standard or ledger, what they normally see is only the last result: a smooth black surface.

But the black powder is not the whole process.

For the steel Ringlock and Layher-type components handled through our current coating workshop, the actual surface-treatment route includes sandblasting, chemical pretreatment, electrophoretic coating, drying, surface inspection and grinding, electrostatic powder coating, and final oven curing.

The process can be summarized as:

Sandblasting → Pretreatment → E-Coating → Drying & Surface Inspection → Electrostatic Powder Coating → Oven Curing → Packaging

The important point is simple:

Powder coating starts long before the powder reaches the steel.

Surface preparation underneath the visible coating is a major part of the manufacturing process.

1. Sandblasting: Start with the Steel Surface

Before chemical pretreatment, the steel components are sandblasted according to their actual surface condition.

The purpose is to remove visible contamination left from material storage and fabrication, including:

• surface impurities;

• welding residue;

• rust;

• and other material that should not remain underneath the later coating system.

For welded Ringlock components, this step is especially practical because fabrication does not leave every area of the steel in the same condition. Welded zones, tube surfaces and locally oxidized areas may require cleaning before the component moves into the wet-treatment line.

Media suggestion: Use the close-up photograph of the unfinished steel tubes here. It clearly shows the steel surface before the final black powder-coated finish.

This is why we do not look at powder coating as simply “changing the steel from silver to black.” The visible color comes later. First, the surface has to be prepared.

2. Chemical Pretreatment: Cleaning Before Coating

After sandblasting, the Ringlock components enter a multi-stage pretreatment process.

According to the process used by our current coating workshop, the sequence is:

Degreasing → Water Rinse → Acid Pickling → Water Rinse → Surface Conditioning → Phosphating → Water Rinse

Each stage has a practical purpose.

Degreasing removes oil and other contamination. Acid treatment helps clean oxides and remaining surface contamination. The rinsing stages prevent one treatment bath from simply carrying contamination into the next. Surface conditioning and phosphating prepare the steel surface before the following coating process.

The workshop describes the objective as removing oil, oxides, dust and other impurities while forming a phosphate conversion layer on the surface.

This part of the process is easy for a buyer to overlook because none of it can be seen once the finished black component arrives.

But if you only look at the final color, you are looking at the last page of the story.

For readers who want to understand the wider relationship between steel materials, components and manufacturing methods, our Material & Component Knowledge section provides the broader context.

Media suggestion: This is the best position for the video showing batches of components moving through the liquid treatment tanks.

3. E-Coating: A Separate Layer Before Powder Coating

One of the most important differences in this steel-component process is that the Ringlock parts do not go directly from cleaning to powder coating.

They first pass through an electrophoretic coating process, commonly called e-coating.

According to the coating workshop's process specification, the treatment also allows electrophoretic coating to enter approximately 20–30 cm into the tube ends.

That detail matters because a tubular Ringlock component does not consist only of the outside surface that we can easily see.

A finished standard, ledger or brace has external surfaces, welded areas, openings and tube interiors. The coating workshop therefore uses e-coating as part of its rust-protection treatment before the powder-coated finish is applied.

However, this should not be misunderstood as a corrosion-life guarantee.

The supplied process information tells us how the components are treated. It does not provide a verified salt-spray duration, corrosion category, service-life calculation or outdoor-lifetime guarantee.

Those are different claims and would require corresponding test data.

4. Drying at the Workshop's Specified Oven Setting

After e-coating, the Ringlock components are hung on the production line and moved into the drying stage.

For the process documented by our current coating workshop, the oven is set to:

210°C

At this stage, the purpose is to dry the electrophoretic coating before the component proceeds to final surface preparation and powder application.

The temperature shown here should be understood correctly.

It is the oven setting specified in this coating workshop's current process, not a statement that every Ringlock component from every manufacturer must always be processed at exactly 210°C.

Different coating systems, powder specifications and processing lines may use different production parameters.

5. Inspection, Grinding and Cleaning Before Powder Application

Coming out of the drying stage does not automatically mean that the component is ready for powder.

The surface is inspected first.

Where an area is not sufficiently smooth, the workshop uses a pneumatic grinder with 100-grit abrasive to correct the local surface.

The component is then:

ground where necessary → wiped → cleaned with high-pressure air

This small step explains something that is common in real manufacturing but often disappears from simplified process diagrams:

A production line still needs human inspection between major automated processes.

A tube can have gone through cleaning, phosphating, e-coating and drying and still have a local surface area that needs attention before the visible finish is applied.

The objective at this point is not to redesign or structurally modify the component. It is simply to avoid carrying an obvious surface irregularity or loose contamination into the final powder-coated layer.

Media suggestion: A close-up video or photograph of workers inspecting, grinding or air-cleaning the components would be particularly valuable here.

6. Electrostatic Powder Coating

Only after these earlier stages does the process reach what most customers simply call “powder coating.”

The steel components are hung on the coating line and powder is applied electrostatically.

Before and during production, the workshop checks items including:

• the coating equipment;

• the required product color;

• and the powder being used.

This is the stage that determines the visible colored finish of the finished Ringlock component.

Black is common for event structures, but powder coating is not inherently limited to black.

Where a project requires a different finish, the color should be specified by an exact RAL color code rather than by a general description such as “dark grey,” “blue” or “red.”

Customers who need another color can use our RAL Powder Coating Color Options as a selection reference.

Screen colors are only approximate. Where accurate color matching is important, the RAL number or a physical reference should be confirmed before production.

7. Final Oven Curing

After electrostatic powder application, the components return to the oven so that the powder-coated surface can cure.

For the documented process used by our current coating workshop, the curing oven is set to:

220°C

This is a different stage from the earlier 210°C drying process.

The distinction is important:

210°C stage: drying after electrophoretic coating
220°C stage: curing the final powder-coated surface

Once curing is complete and the finished coating has been checked, the components can proceed toward packing.

Media suggestion: The video showing black Ringlock standards hanging on the conveyor is suitable here because the reader can now connect the finished appearance with all of the preparation stages described above.

What the Complete Process Looks Like

Why Steel Ringlock Uses a More Involved Pretreatment Route

A useful way to understand this process is to separate what the customer sees from what the manufacturer has to deal with.

The customer sees the final black standard.

The coating process has to deal with the steel underneath it: fabrication residue, rust, oil, oxides, welded areas, tube openings and local surface irregularities.

That is why “powder coated” by itself does not describe the complete manufacturing treatment.

For the Ringlock components documented here, the visible powder layer sits at the end of a much longer preparation sequence.

The complete Ringlock system itself contains different component families—standards, ledgers, braces and related parts—and the surface finish is only one part of how those components are manufactured and supplied. You can see the broader system through our Ringlock Structure System.

Material choice, connection method and component construction are also separate from surface treatment. These relationships are explained further in our Connection & Material System.

What This Process Does Not Automatically Prove

A photograph of a black powder-coated Ringlock component cannot, by itself, tell you:

• how long the coating will last outdoors;

• a salt-spray test duration;

• a corrosion classification;

• coating thickness;

• a specific coating standard;

• or the service life of the complete structure.

The process information supplied by our coating workshop confirms the manufacturing route and current process settings described above.

Claims about verified corrosion performance, coating thickness or compliance with a specified coating standard require the relevant inspection or test documentation.

This distinction is important because a manufacturing process and a verified performance result are not the same thing.

Powder Coating Is the Last Visible Step, Not the First Manufacturing Step

When a customer asks us whether a Ringlock structure can be powder coated black or another color, the short answer may simply be “yes.”

But from a manufacturing point of view, the better question is:

What happens to the steel before the powder is applied?

For the process shown here, the answer is:

surface preparation → chemical pretreatment → phosphating → e-coating → drying → inspection and local grinding → electrostatic powder coating → curing.

The black finish is what you see.

The preparation underneath it is what you do not see.

FAQ

Is black the only powder coating color available for Ringlock structures?

No. Other powder coating colors can be produced according to project requirements and the colors available from the coating supplier. For custom colors, provide the required RAL color code rather than only a general color description.

Does the powder coating process also treat the inside of the steel tube?

In the process documented here, the electrophoretic coating stage reaches approximately 20–30 cm inside the tube ends. This should not be interpreted as saying that the final powder coating covers the entire internal surface of the tube.

Why is e-coating used before powder coating?

In our current steel Ringlock coating process, e-coating is used as part of the anti-rust surface-treatment system before the final powder-coated finish. The supplied process documentation does not provide a specific corrosion-life or salt-spray performance figure.

Are 210°C and 220°C universal powder coating temperatures?

No. These are the oven settings specified in the current coating process documented by our coating workshop: 210°C for drying after e-coating and 220°C for final powder curing. They should not be treated as universal parameters for every powder coating system.

Need a Custom Powder-Coated Ringlock Structure?

For a quotation, send us:

• the Ringlock structure or components you need;

• required dimensions or component specifications;

• quantity;

• required RAL color, if not standard;

• intended application;

• and reference drawings or photos when the configuration is customized.

We can then confirm the product configuration and the available surface-finish options before production.