Aluminum Heat Sink Soldering
Superior Flux offers Aluminum Solder Paste and flux solutions for direct soldering of aluminum heat sinks. Superior Flux’s technology eliminates the need for costly plating operations in heat sink fabrication.
Please review our selection of aluminum soldering Video Links.
AL26-Series
| Superior Flux Number | AL26-Series |
| Description | Aluminum Solder Paste |
| Rec. Base Metals | Aluminum to: Aluminum, Copper and Brass |
| Rec. Solders | 99.3Sn/0.7Cu; SN100C; 96.5Sn/3.5Ag; 99Sn/1Ag |
| Rec. Temp Ranges | Dependent upon alloy |
| SDS | Link |
| Spec. Sheet | Link |
AL261-143-75
| Superior Flux Number | AL261-143-75 |
| Description | Aluminum Solder Paste – Low Temp |
| Rec. Base Metals | Aluminum to: Aluminum, Copper and Brass – for Heat Sink Applications |
| Rec. Solders | Proprietary low-temp solder |
| Rec. Temp Ranges | Capable of soldering under 200°C |
| SDS | Link |
| Spec. Sheet | Link |
No. 1260
| Superior Flux Number | No. 1260 |
| Description | Honey Consistency Soldering Flux |
| Rec. Base Metals | Aluminum to: Aluminum, Copper and Brass |
| Rec. Solders | Tin-Zinc: 91Sn/9Zn, 80Sn/20Zn 70Sn/30Zn, Tin-based alloys |
| Rec. Temp Ranges | 177-288°C / 350-550°F |
| SDS | Link |
| Spec. Sheet | Link |
No. 1261
| Superior Flux Number | No. 1261 |
| Description | Liquid Aluminum Soldering Flux – Dip Soldering Aluminum Magnet Wire |
| Rec. Base Metals | Aluminum to: Aluminum, Copper and Brass |
| Rec. Solders | Tin-Zinc: 91Sn/9Zn, 80Sn/20Zn 70Sn/30Zn, Tin-based alloys |
| Rec. Temp Ranges | 177-288°C / 350-550°F |
| SDS | Link |
| Spec. Sheet | Link |
No. 1265
| Superior Flux Number | No. 1265 |
| Description | Aluminum Soldering Flux – Dispensable |
| Rec. Base Metals | Aluminum to: Aluminum, Copper and Brass |
| Rec. Solders | Tin-Zinc: 91Sn/9Zn, 80Sn/20Zn 70Sn/30Zn, Tin-based alloys |
| Rec. Temp Ranges | 177-288°C / 350-550°F |
| SDS | Link |
| Spec. Sheet | Link |
Contact Us to see if the alloy you are looking at is RoHS compliant. The Superior Nos. 1260, 1261, and 1265 are RoHS compliant.
Please review the following papers on aluminum soldering:
Direct Aluminum Solder Paste (IMAP Thermal Management Workshop – Palo Alto, CA, 2011)
Soldering Aluminum (SME International Brazing & Soldering Conference – Orlando, FL, 2009)
Heat sinks are often made of aluminum. Rather than directly soldering the aluminum heat fins to their aluminum or copper base, the components are typically tin-plated. This plating step is not only costly, but it involves hazardous chemicals. Our heat sink soldering technologies offers the opportunity to bypass plating and directly solder the aluminum components of the heat sink. Our aluminum solder paste can be applied in the same way that traditional solder paste is applied. Its residues do, however, need to be cleaned after soldering.
One primary consideration that has to be made when soldering aluminum is the aluminum alloy that is being soldered:
| Aluminum Alloy | 1100, 1145, 1050, 3003 | 1350, some 8000 series | 6061, 6063, 5050 | 4000, 7000, 2000 series |
| Solderability | Great | Good | Poor to not solderable | Very poor |
| Best Solder Alloy | 91Sn/9Zn; 96.5Sn/3.5Ag; 80Sn/20Zn 70Sn/30Zn, Tin-based alloys | 99.3Sn/0.7Cu; SN100C; 96.5Sn/3.5Ag; | 91Sn/9Zn; SN100c | None |
| Solderable via Solderpaste | Yes | Yes | No | No |
| Can be tinned with SN100C | Yes | Yes | Yes | Unlikely |
The following are options available for heat sink soldering
Superior AL26-Series Aluminum Solder Paste is an all-in-one aluminum soldering solution. It has both aluminum flux and solder powder. Available alloys include 99.3Sn/0.7Cu, 96.5Sn/3.5Ag, 99Sn/1Ag, SAC-305, and SN100C. This aluminum solder paste shows excellent soldering characteristics when joining aluminum to aluminum, nickel-plated surfaces, copper, and brass. If the application calls for precision dispensing, then this paste is ideal. This solder paste can also be used for heat sink applications where copper piping is not built into the aluminum heat sink device. (See AL261-143-75 for heat sink applications where copper piping is built into the aluminum heat sink). Flux residues are water soluble and must be washed off after soldering. Our aluminum solder paste creates a true inter-metallic bond between the solder and aluminum substrate. This means the resulting joint is less brittle.
Superior AL26-143-75 contains a proprietary solder alloy that is specifically formulated for the direct soldering of heat sinks. It solders at temperatures under 200°C, thus protecting copper piping built into the heat sink. Most importantly, Superior AL26-143-75 allows for direct aluminum-aluminum or aluminum-copper soldering in heat sink fabrication, getting rid of the need for plating in heat sink applications. Eliminating plating not only translates into greatly reduced costs, but eliminates the associated hazardous chemicals from the work environment. Post-solder residues are water-soluble and should be cleaned after soldering.
Superior No. 1260 is a general purpose aluminum soldering flux that has a honey-like consistency and color. It is high activity, organic based and chloride-free. No. 1260 is formulated for soldering joints made of aluminum-aluminum, aluminum-copper, aluminum-brass, and aluminum to plated terminals. No. 1260 is effectively used with solder foil in heat sink applications. Post-solder residues are water-soluble and should be cleaned post soldering. Superior No. 1260 can also be utilized in joining aluminum to difficult-to-solder metals like stainless steel, kovar, or nickel alloys.
Superior No. 1261 aluminum tinning flux offers the effectiveness of No. 1260 in a more liquid form. It is effective for heat sink, wire tinning, soldering cable connectors, and also dip soldering aluminum mag-wire applications. Post-solder residues are water-soluble and should be cleaned after soldering.
Superior No. 1265 aluminum paste flux was formulated for applications where a paste flux is wanted over a liquid one. Superior No. 1265 can be precision dispensed with a syringe or system and can be spread from there. In heat sink applications, No.1265 can be used in tandem with preforms or solder foil. Once applied, the aluminum paste flux adheres to the desired location without spreading or dripping off. Post-solder residues are water-soluble and should be cleaned after soldering.