How to select a good kitchen sink?(5) – Manufacturing Process

1. Bottom treatment method of sink

There is usually a coating on the bottom of the sink.

A better coating is to use mortar to spray the entire back of the sink. A common one is a rubber gasket attached to the bottom

This has two advantages.

  • Anti-noise.

The bottom of the water tank is sprayed or glued with rubber sheets, which can reduce the noise caused by the impact of tap water on the basin floor and play a buffering role.

  • Anti-condensation water.

Although the sink will not leak, condensation of water vapor is easy to occur on the outer wall of the sink. 

If frozen food is placed in the sink, water vapor will condense on the bottom of the basin to form water droplets, which will damp the inside of the cabinet.

Spraying a suitable coating on the bottom of the sink can reduce or even eliminate the temperature difference and prevent the formation of water droplets.

The high-quality coating also has a certain moisture absorption function and protects the cabinet from flooding.

The world’s first coated sink was produced in Europe.

At that time, a “silent revolution” began in the kitchen. Later, sink manufacturers around the world followed suit and took this as a selling point and positioned it as a high-grade sink. 

But in less than 10 years, this technology was eliminated in Europe. 

At present, some international brand manufacturers have adopted silencer cushions, mainly to reflect the authenticity of their hygiene and materials.

 2. Molding process of sink

The stainless steel sink molding process includes welding method and integral forming method.

  • Welding method

Welding quality is one of the most critical factors affecting the service life of water tank. 

Good welding can prevent rusting, and the sink is flat, smooth, free of rust spots and burrs. 

At present, double bowls sink with a depth of more than 450px are basically welded.

Because the double bowls stretch 450px at the same time (bowl’s depth, not the total height of bowl body plus basin edge), it is the max depth of the processing technology.

At present, the sink with a depth of over 450px produced by regular manufacturers is welded by numerical control wave crest resistance welding, and the quality is up to standard.

It can be divided into two types.

One is the girth welding in which the bowl and the panel are welded together, also called roll welding (bottom welding). 

The bottom welded sink has a beautiful appearance. After treatment, the welded joint is not easy to be found, and the surface of the sink is flat and smooth. 

Someone will doubt its firmness. In fact, the current welding technology mainly includes sub-arc welding and the most advanced numerical control resistance welding. The quality is very good.

The other is that two single bowl are welded together, also called butt welding.

Its advantages is that the bowls and the panel are integrally formed by stretching, which is firm and durable.

Its disadvantages are easy to see welding traces and slightly poor flatness.

In fact, some so-called one-time forming double-bowl sinks are not stamped from a piece of steel, but are welded together by two single bowl.

You can look at the welding spot in the middle of the two bowl from the reverse side.

At present, there is no such technology in the world to make double bowls sink from one steel plate.

  • One-step stretching method (mainly used for single groove)

The one-step molding process is highly praised, and its manufacturing process is difficult. 

It has high requirements on steel plate materials.

It solves the leakage problem caused by the weld seam not withstanding the corrosion of various chemical liquids (such as detergents, stainless steel cleaners, etc.) due to welding. 

However, there are many disadvantages in punching one piece of steel plate into a sink.

(1) The overall thickness of the sink is uneven and thin, mostly about 0.7 mm.

This technology has not been overcome at present. Therefore, some merchants usually coat the bottom of the sink with a thick damp-proof layer so that you cannot know its thickness. A good sink thickness should be 0.8–1.0 mm. 

(2) It can not be made a deep sink. Because if it is too deep, the wall of the sink will be broken due to being too thin.

(3) The one-piece stretched sink generally needs high-temperature annealing, which is generally above 1200 degrees.

After such treatment, the rigidity of the sink will naturally weaken, and the hardness will definitely be reduced.

(4) It is generally a single-layer flanging. There is no “reinforcing rib” in the edge so that the bearing weight is not good.

At the same time, it is difficult to seal water. 

(5) It is difficult to make the whole stretching panel smooth.

The advantage of one-step forming sink is that the material quality is better than that of welding sink, but the process is complicated and the processing is difficult. 

The welding sink’s process is simple. Although the steel plate is not such good, it is cheaper and the thickness of the bottom plate is thicker than that of one-step forming sink.

You may interesting

1. How to select a good kitchen sink? (1) – Sink material

2. How to select a good kitchen sink?(2) – Style

3. How to select a good kitchen sink?(3) – Stainless Steel Sink

4. How to select a good kitchen sink?(4) – Size

5. How to select a good kitchen sink?(6) – Faucet of sink

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