Otto's Original - Quality products since 1901


No clean, alcohol-based flux, synthetic resin, di-carboxylic
acids, halogen-free (WEEE/RoHS compliant)
ISO-9454: 1231 // DIN EN 61190-1-1: L0 (REL0)

Packaging units:
20 l
Application area: Wave soldering (spray- and foam fluxing)
Appearance/smell: colorless to reddish, clear
Solids content: 2.5 Gew.-% (wt.-%)
Density at 20 °C: 0.794 (+/- 0.003) g/ml
Acid number: 22–25 mg KOH/g
Activators: synthetic resin with di-carboxylic acids
Solvents: short-chain alcohols
Flash point: ca. 12 °C
Durability: 6 months
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GSP-2533/RX established over the course of many years, is S-250/FRO’s predecessor. Very good soldering results were achieved regardless of the respective type of system. The cleanliness is very good. GSP-2533/RX is suitable as a wave-solder flux for foam and spray fluxing. It’s not recommended for selective or manual soldering. Please note the shelf life of 6 month.

Practice has shown, that no washing is needed for PCBA properly soldered with this flux. The IC test with needle adapters generally completes without problems.

Customer added value:

  • Very good soldering properties (capillarity, wetting)
  • Broad process window (very high thermal stability, good activity over a long interval)
  • Very good residue behaviour (very clean, high SIR)

Questions about our products?
We will advise you by phone 06123 / 7046-0.