Soldering cast iron - brazing or gluing?

Some experts swear to weld cast iron. But the welding equipment and accessories are so special and the required skills are so great that it is generally discouraged. Other professionals claim casting would not be weldable. But it is possible, at least with some tricks, to solder cast iron. Whether you would rather solder or glue, we show here.


Welding cast iron is not worth it for a handyman because of the high carbon content in the material rather not. The equipment and electrodes that are required usually outweigh the cost of a new cast part. In addition, the special training is usually missing, because even a welder rarely welds cast iron really well.


Which solder additive is the right one for soldering cast iron depends on the carbon content in the casting. In the case of machine parts, for example, this proportion ranges between 2.5 and 4 percent. For brazing cast iron, nickel silver solders with specially adapted fluxes are used. You should seek advice as to which solder is exactly suitable for your workpiece, as the graphite content in the casting can vary.

The material should be heated before soldering. It does not have to be as hot as welding, where the temperature of the workpiece should be about 450 degrees, but should still be warmed up.


In many cases, gluing with two-component adhesive is the best way to reassemble cast iron. Although this is not invisible, similar to the brazing will remain visible here, the splice. However, cast iron makes it easy to paint. This makes the repair invisible at the same time and protects the workpiece from the weather and the rust at the same time.

Unfortunately, not every glue works and the glue needs some preparation. But at the same time the cast piece can not be further damaged by the gluing process.

Tips & Tricks

In many cities there are welding courses in vocational schools. If your workpiece still has a certain value, you can address the teaching staff there. Most of the time, they like to insert a small course with this difficult material. So everyone has something like this and your workpiece will be professionally repaired.

Video Board: How to Repair Cast Iron with JB Weld