How to Weld Aluminum

Try to identify the league if possible. Aluminum can be welded although it is not the easiest material to work with.Many objects are built with aluminum alloys:most of them can be soldered following the same procedures, although some cause more problems and require specific tools.The aluminum alloy is identified with a letter or number, so check if there are any specific instructions or requirements.Unfortunately, aluminum alloy objects without labels or markings are not easy to catalog, and professional identification guides are only useful if welding aluminum is your job.The only solution is to try welding and hope to get lucky.

• If you want to join aluminum to another material, the characteristics of the aluminum are usually the limiting factor, so precise identification of the alloy is not essential.Remember that some combinations, such as steel and aluminum, are very difficult to make and require special welding methods instead of a bonding material.

Choose a low-temperature bonding material. Aluminum has a relatively low melting point (660°C) which, combined with its high thermal conductivity, makes welding with general bonding materials virtually impossible.You must use a filler material with a low melting temperature and will need to be ordered online.Usually a combination of aluminium, silicone and/or zinc is used, but always read the label to be sure it is the right product for the type of work you want to do (for example aluminium-aluminium or copper-aluminium welding).

• Technically, bonding materials that melt above 450°C bond materials together to brazing and not for welding.Soldering creates a stronger bond, but soldering is preferred when joining electrical circuits and other delicate materials.
• As much as possible, avoid all filler materials that contain lead.

Choose a flux. It is essential that it is specific for aluminum or for the type of combination you want to weld (much more than the bonding material).The best choice is to purchase it together with the filler material, since they will have to cooperate to produce a good weld.The operating temperature of the flux must be very close to the melting point of the soldering material;Buy one for brazing if you have chosen a solder that melts above 450°C.

• Some brazing fluxes are not suitable for soldering thin aluminum foil or wire.In that case, look for the ones that say "for immersion brazing."

Choose a heat source. You can use a welding machine to join aluminum wires, but other types of jobs require a propane torch.Low temperature torches are usually used with the flame reaching 315-425 °C.

• If the torch is not suitable for the environment you will be working in, get a 150 watt welder.

Purchase optional materials. You will need a clamp if you need to join more than one piece of metal together instead of making repairs to an object.A pickling solution to remove post-weld oxides is also highly recommended.Some resin-based fluxes need to be cleaned up with acetone.

Set up a safe workstation. Protect yourself from toxic fumes by wearing a respirator and working in a well-ventilated area.A mask or protective glasses are also highly recommended;wear clothing made of natural fibers and don't forget a pair of thick leather gloves.Keep a fire extinguisher handy and work only on fireproof surfaces.