Steel is the skeleton of modern construction and infrastructure projects. But this skeleton is vulnerable to corrosion (rusting). Hot-dip galvanizing is the world’s most effective way to protect steel. However, there is a critical detail that is not talked about much in the sector, but determines the fate of quality: Size of Galvanized Boiler.
In many galvanizing plants in Turkey and around the world, pool lengths average between 6.5 and 8 meters. What if your project includes 10-meter, 12-meter lighting poles or huge steel constructions? At this point, manufacturers necessarily resort to the “Double Dipping” method. Although this method seems to solve the problem, it brings with it serious aesthetic and structural risks.
In this guide, we will examine the vital differences between single dip and double dip, the technical advantages that a large pool can bring to your project and the capacity power of IES Galvaniz in all its transparency.
1. Why “Boiler Size” is Important in the Galvanizing Industry?
Galvanizing is based on the principle of completely immersing the steel in a bath of molten zinc at 450°C after cleaning. Ideally, the material enters and exits the pool as a whole, all at once.
Standard Pools vs. IES Galvanized Pool
You cannot cover a 12-meter TEDAŞ lighting polein a 7-meter pool, which is the industry standard. Half of the pole sticks out.
- IES Difference: Our pool is 14 meters long. This means that 12-meter poles, 13-meter power transmission line angles or long IPE profiles can be coated in one go without any difficulty.
Rising Demand for Long and Bulky Materials
Modern architecture and engineering now favor longer, monoblock steels with fewer joints.
- The stadium roof trusses, which used to be made in pieces, are now welded together on the ground and are intended to be removed in one piece.
- Energy pylons go higher.
- Highway information sign (Gantry) poles are reaching gigantic proportions.
The only way to meet this demand is to have a galvanizing pool of the appropriate size for the production capacity.
2. What is Double Dipping and What are the Risks?
If the material is longer than the pool, “Double Dipping” becomes mandatory. In this process, one half of the material is first dipped into the pool, removed, inverted in air and then the other half is dipped. Although it sounds simple, it is a metallurgically risky process.
A. Aesthetic Defect: “Overlap Mark”
A thick, dark and rough strip is formed in the middle of the material, at the intersection of the two dipping processes.
- Conclusion: Especially in decorative poles or architectural steel used in city centers, this mark deteriorates the visual quality. Even if it is dyed, the bulge underneath will be visible.
B. Thermal Stress and Distortion – THE BIGGEST RISK
Steel expands when it enters 450°C. In double immersion, one half of the pole expands at 450°C, while the other outside half is at room temperature.
- Rule of Physics:This extreme temperature difference (Thermal Shock) on the material increases the internal stresses of the steel.
- Consequence:The pole can bend or twist “like a banana” when it comes out of the pool. It is impossible to install a crooked pole on site; the bolt holes do not meet each other, it is aesthetically unacceptable.
C. Coating Thickness Difference
Since the middle zone (overlap zone) enters the pool twice, the coating thickness at that point is much higher than elsewhere.
- Risk: Too thick galvanizing (e.g. 200-300 microns) becomes brittle. During transportation or assembly, the galvanizing in that area may flake off (Flaking).
3. 5 Critical Advantages of Single Dip Technology
1. Homogeneous Coating Thickness
The material enters and leaves the pool in one go. Every square millimeter of the surface is in contact with the zinc for the same amount of time.
- Benefit:A standardized (e.g. 85 micron) and homogeneous coating from the base to the top of the pole. There is no weak point.
2. Flawless Aesthetics
There are no additional marks, color difference, discharge or blistering. The surface is smooth and one color.
- Benefit:Provides a “prestigious” appearance in architectural projects, park-garden lighting and visible steel structures (shopping mall roofs, airports).
3. Structural Integrity (Inclinability)
The entire material heats up and cools down at the same time. Thermal expansion is balanced.
- Benefit:Even a 12-meter long and thin polygonal pole is straight as a string. On the construction site, assembly teams do not have to deal with correcting curvatures, increasing the speed of assembly.
4. Corrosion Resistance
The “joint” in the double dip is where the coating is most uneven and where corrosion is most likely to start.
- Benefit: There is no weak link that can be a “corrosion starting point” in a single immersion. Protection life guaranteed.
5. Speed and Efficiency
Double dipping doubles the crane operation, extending the duration.
- Benefit: At IES Galvaniz, the process is finished in one go. This speed is the secret of our 120,000 tons capacity and fast deadlines.
4. IES Galvanizing Plant Infrastructure and Capacity
It’s not enough to have a big pool; you need an infrastructure to carry giant materials to that pool.
Boiler Dimensions: 14m x 1.8m x 3.2m
- 14 Meter Length:Turkey’s tallest lighting poles, flagpoles and power transmission line elements.
- 3.2 Meters Width: This dimension is very critical. It allows large lattice structures, container chassis or large stadium trusses to fit into the pool. In narrow pools these materials cannot be covered.
- 1.8 Meter Depth:Allows full immersion of bulky parts.
Annual Capacity of 120,000 tons
Large projects (Northern Marmara Highway, Istanbul Airport, etc.) require thousands of tons of steel. Small workshops cannot meet this demand. With its integrated plant and automation-controlled crane systems, IES Galvaniz ensures that the largest projects proceed without bottlenecks.
5. Which Products Require a 14 Meter Pool?
If you have one of the following product groups, “Single Immersion” is not a choice for you, but a technical necessity:
- TEDAŞ Type Lighting Poles: 10m and 12m polygon poles.
- High Voltage Line Poles:Long main struts (Legs) of power transmission lines.
- Projector Poles:The lower parts of 15-20 meter poles used in stadium and intersection lighting.
- Steel Construction Trusses:Roof trusses for factory buildings, hangars and sports halls.
- Ship and Harbor Pier Piles:Long pipes and profiles to enter seawater.
- Totem and Advertising Poles: Giant signs that require a monolithic appearance.
14 Meter Galvanized Boiler and Single Dip Technology
6. Impact on Project Economics: Is Single Immersion More Expensive?
At first glance, it may seem expensive to work with a large plant. However, from a “Total Cost of Ownership” perspective, single immersion is much more economical.
- Zero Rejection Rate: It is a big hidden cost that poles that are warped (bent) as a result of double dipping are not accepted at the construction site, sent back and tried to be corrected. With IES Galvanized, this risk is zero.
- Less Labor:In double immersion, the crane and suspension operation is twice as expensive. This cost is reflected in the price. We can offer competitive prices as single dipping is more efficient.
- Longevity: Homogeneous coating with no seams contributes to the operating budget by postponing maintenance costs.
7. Technical Comparison Table: Single Immersion vs. Double Immersion
A brief summary to clarify the decision:
| Feature | Single Dipped (IES Galvanized) | Double Immersion (Standard Pool) |
| Appearance | Smooth, one color, seamless | Dark stripe down the middle, rough joint |
| Structural Risk | None (Minimum thermal stress) | High (Risk of bumping, bending) |
| Coating Thickness | Homogeneous at every point | Excessively thick at the joint (risk of shedding) |
| Corrosion Resistance | Maximum | The joint can be a weak point |
| Ease of Assembly | Excellent (Flat product) | Difficult (If there is curvature, the holes do not meet) |
| Termin Time | Fast | Slow (Double operation) |
8. Frequently Asked Questions (FAQ)
- I have a material more than 14 meters long, can you cover it
Yes. In our 14-meter pool, we can also cover materials up to 20-22 meters using the “Double Dipping” technique. But we cover everything up to 14 meters in one go.
- Is there a price difference for single dip galvanized?
No, on the contrary, since our operational efficiency is high, we offer advantageous prices that are competitive with the workshops under the stairs in the market and incomparably more advantageous than our quality.
- Why the width of the pool matters
Not only length but also width is restrictive. For example, a 3 meter wide truss or container chassis will not fit in standard (1-1.5m wide) pools. IES Galvaniz’s 3.2 meter wide pool is one of the rare solutions in Turkey for 3D volume parts.
Big projects require big solutions.
İES Galvaniz does not put your steel at risk with its giant 14-meter galvanizing boiler and high-tech production line. You are at the right address for products that are not warped, without joint marks, homogeneously coated and guaranteed for 50 years.
Get a Quote for Your Project with Single Immersion PrivilegeGet a Quote.
Send your material list and technical drawings and we will offer the most suitable galvanized solution.
You may also be interested in the following article.
https://www.iesgalvaniz.com/ies-galvanizden-yeni-nesil-kaplama-cozumleri/
