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Alutop – Brazing Aluminium
ALUTOP is a trademark for specialized products for joining and processing aluminum. Our extensive industry experience has allowed us to develop a wide range of proprietary materials for brazing aluminum and its alloys under our own ALUTOP brand.
As a supplier of diverse technologies, ALUTOP offers products from renowned global manufacturers, allowing us to present a consolidated product range. We offer products for a wide range of industries and applications in various sectors: precision mechanics, electronics, automotive, aerospace, machine building, medical equipment, and many others.
The materials we offer are manufactured under ISO certification, National Institute of Hygiene (PZH) approvals, and European Union quality approvals. Thanks to our extensive offering, we provide comprehensive services to businesses in specialized production and operational resources.
Our Offer
ALUTOP manufactures aluminum soldering paste, brazing rings, aluminum wires, and provides services related to flame brazing of aluminum.
Pastes and Fluxes
Our brand's pastes for soldering aluminum and its alloys are used in numerous industries, including automotive, home appliances, air conditioning, and refrigeration.
Aluminum Wires
Aluminum wire is typically used as a conductor in moving coils. Due to its lower density, the coil weight can be reduced by one-third compared to copper.
Services
ALUTOP provides professional aluminum flame soldering services.
Pastes and Fluxes – Characteristics and Applications
With the appropriately selected paste, we can permanently join configurations of: aluminum-to-aluminum, aluminum-to-copper, and aluminum-to-stainless steel using burners with the appropriate flame or CAB (Controlled Atmosphere Brazing) technology.
The joint should be thoroughly cleaned with steam, water, or solvents, and the soldering surface must be dry before heating. Apply the paste with a brush or a brush – covering an area 1.0–1.5 cm wider than the soldering area is sufficient. Excess paste around the joint can negatively impact the aesthetics of the joint.
Non-corrosive pastes
These are classified as non-corrosive because their soldering residues do not damage the joint and do not cause corrosion if left. A cesium compound is added to some products, which provides very effective results when machining aluminum alloys with high magnesium and copper content (preventing the deposition of magnesium and copper oxides on brazed surfaces).
These pastes are widely used in open flame, induction, or controlled-atmosphere furnace soldering. They do not require additional cleaning after the soldering process (optional cleaning using mechanical methods or glass microbeads for a perfect visual result).
Pastes with non-corrosive flux
| Product name | Cesium | Working temp. range | Notes and application |
|---|---|---|---|
| NKO 200 | No | 560°C - 590°C | Used for brazing aluminum (4047) using CAB or flame brazing. General purpose soldering with AlSi12 wires. |
| NKO 200 Cs | Yes | 420°C - 470°C | Used for brazing materials with high magnesium or copper content (e.g., 6061, 6063). Particularly useful for capacitor repair using low-temperature flame brazing with AlZn2 and AlZn15 wires. |
| Paint Flux | No | 560°C - 590°C | Used paint for brazing aluminum using CAB or flame brazing. |
Pastes with non-corrosive flux and filler metal
| Product name | Cesium | Working temp. range | Notes and application |
|---|---|---|---|
| MNKO - 70/30 | No | 560°C - 600°C | General purpose, high metal content, works well with automatic dispensing equipment. Often used for pre-soldering. |
| MNKO - 70/30 Cs | Yes | 470°C - 600°C | Enriched with a cesium alloy, it's ideal for soldering materials with a high magnesium content at lower temperatures. Often used as a pre-solder. |
Available package sizes: 0.25kg, 0.5kg, 1.0kg, 5.0kg. All products are sold ready-to-use (mix thoroughly before application).
Aluminum Brazing Process Technology
Process Difficulties and Barriers
Aluminum brazing is considered a difficult process due to the specific physicochemical properties of the material:
- Low melting point of pure aluminum (approx. 660°C) and its alloys (falling even below 500°C).
- High thermal conductivity, high thermal expansion, and significant volumetric shrinkage upon solidification.
- High chemical affinity for oxygen, resulting in the immediate coating of the surface with a difficult-to-melt (oxide melting point is as high as 2050°C), resistant, and non-wettable oxide layer (Al₂O₃) by liquid solders.
Selecting a solder and removing oxides
Due to the low melting point of the base alloy, only Zn-Al solders (melting range 382–450°C depending on the composition) and Al-Si solders (soldering temperature 570–585°C) are used for soldering.
Our ALUTOP product range solves the problem of removing oxide layers. When selecting a flux, it is crucial to match its activity temperature range with the pour point of the chosen solder. The corrosiveness of flux residues (slag) should also be monitored – fluxes containing alkali chlorides and fluorides require thorough washing with water (e.g., KO100 corrosion paste), while non-corrosive fluxes can safely remain on the joint.
Flame soldering process
A propane-butane + oxygen or propane-butane + air gas mixture is most often used to heat the components. The moment the applied paste liquefies indicates that the correct component temperature has been reached. At this point, the filler metal (solder) is introduced, which melts and is drawn into the assembly gap by capillary action. The flame must be precisely controlled in the joint area, and once the filler metal has fully melted, heating must be immediately stopped to protect the components from melting.
ALUTOP cooperates with numerous domestic and international companies, such as ABIS. We have agreements on mutual cooperation and distribution of industrial chemicals. Our clients include companies in the automotive, household appliance, refrigeration and air conditioning, and furniture industries. Our products have received technical approval and are successfully used by companies such as the Volkswagen Group, BMW, Skoda, Valeo, Mahle, the Bosch-Siemens Group, and many others.
Our modern high-bay warehouse allows us to store a stable quantity of goods, allowing us to handle even the largest production orders without risk of delays. We strive to operate professionally, following the principle: to ensure high-quality goods – to deliver them on time and at the specified location. We provide our clients with favorable purchasing conditions and flexible transportation.