ESAB Knowledge center.
Handling and Storage of Welding Fluxes
By carefully selecting raw materials and optimizing manufacturing conditions the Exaton fluxes have guaranteed as-delivered moisture content from the factory.
Normally, the fluxes are delivered in steel drums, each containing 25 kg (55 lbs). Each pallet has a net weight of 500–1000 kg (1100–2200 lbs) and is shrink wrapped in plastic or packed in wooden crates before delivery from the factory.
To maintain the as-delivered moisture content, as long as possible, the handling and storage of the flux must be done according to the following requirements.
Transportation of the flux must be done in covered vehicles.
- Unbroken pallets must be shrink wrapped in plastic or kept in wooden crates.
- Unprotected containers must be repacked within one hour, otherwise they must be scrapped.
- Maximal two pallets may be stapled on each other.
Unopened flux drums must be kept under properly maintained storage conditions as follows:
- Temperature: 20 ± 10°C.
- Relative humidity: as low as possible, not exceeding 70%.
- Flux stored according to these conditions has a lifetime of max 5 years.
- The content of unprotected flux hoppers must, after an 8 hours' shift, be placed in drying cabinet or heated flux hopper at a temperature of 150 ± 25°C.
- Remaining flux from opened drums must also be placed at a temperature of 150 ± 25°C.
- Moisture and oil must, in a suitable way, be removed from the compressed air used in the recirculation system.
- Addition of new flux must be done with the proportion of at least one part new flux to three parts recycled flux.
- Foreign material such as mill scale, dross etc., should be removed by a suitable sieving.
When handled and stored as above, the Exaton fluxes can normally be used as they are. If, however, a severe application is considered, as given by the material specification, rebaking of flux is recommended.
Furthermore, if flux, due to unfavorable handling or storage, has picked-up moisture, rebaking can return the flux to its original state.
Rebaking shall be performed as follows:
- 350 ± 25°C for minimum 4 hours.
- Rebaking must be done on shallow plates with a flux height not exceeding 50 mm.
- Rebaked flux, not immediately used, must be kept at 150 ± 25°C before use.