Do you have graphite molds for exothermic welding?

Yes. We make graphite molds for exothermic welding using molded or isostatic grades based on reuse cycles and joint geometry.

How many welds does a graphite mould allow?

It depends on the configuration, the charge size, and field handling. The cavity erodes with each pour and actual reuse is set by surface condition; preheating and careful cleaning extend it.

Are moulds made for non-standard configurations?

Yes. Crosses, taps, cable-to-rod and cable-to-plate joints, and proprietary geometries are machined to drawing or from an existing mould, with their crucible and tap hole.

Why does copper not stick to the mould?

Because molten copper does not wet graphite, so the connection releases without sticking and the cavity cleans easily between pours.

What care extends mould life?

Keeping it dry, preheating before the first pour of the day, cleaning without tools that scratch the cavity, and avoiding knocks on the closing faces.

Graphite mold for exothermic welding of copper cables

Electrical applications

Exothermic welding molds

They facilitate the joining of metals through controlled exothermic reactions.

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Reaction welding mould

Also known as: Graphite moulds for exothermic welding · Cadweld-type welding moulds · Copper thermite welding moulds · Moulds for grounding connections

[ Technical summary ]

Exothermic welding joins copper conductors through a reaction that produces molten metal inside the mould. The mould receives that pour at very high temperature for a few seconds, cools, and is used again. Graphite is the usual material because it tolerates that repeated thermal cycle, is not wetted by copper — so the connection releases cleanly — and allows the cavity, crucible, tap hole, and exact seating for each conductor configuration to be machined.

[ Problem it solves ]

Contain and shape the reaction pour over the conductor joint, withstanding severe repeated thermal shock and releasing the connection without sticking.

Operating conditions

Exothermic welding
Copper connections

When it is suitable

Permanent copper connections are made by exothermic reaction
The conductor configuration is not available as a standard mould
The mould must be reused in the field a number of times
The connection must come out clean and free of adhering flash

When it may not be suitable

The mould is used damp or without preheating after cleaning
The cavity is cleaned with hard tools that wear it away
The configuration requires a mould that cannot be aligned with the conductors

Process challenges

Cavity wear
Limited reuse
Joint quality

Advantages

High thermal resistance
Precise cavities
Machined replacement

Limitations

Wear from arcing or electrical erosion
Conductivity and density must be calibrated to the process
Some grades are not suitable for high purity

[ Critical selection variables ]

These variables define the grade and the geometry. Actual values are confirmed against the grade datasheet.

Thermal shock severityDecisive
Geometry and tolerancesDecisive
Conductor size and typeDecisive
Thermal and duty cyclingDecisive
Operating temperatureRelevant
Surface finish required on the partRelevant

[ Required material properties ]

Properties that guide selection. Numerical values come from each grade's datasheet.

Critical properties

Machinability
Thermal shock resistance
Non-wetting by molten metal
Grain size

Secondary properties

Bulk density
Dimensional stability
Thermal conductivity

[ Related ]

[ Frequently asked questions ]

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Technical content reviewed by ESGRAF — Last reviewed: September 8, 2026

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