TWI Frequently asked questions
Providing that the operating temperature of the product remains below about 100°C, it is generally considered that the residues of RMA soldering fluxes complying to BS EN 29454 will cause no serious corrosion problems. However there is a risk that the residues, which are inherently sticky, will adversely affect electrical test probes (eg give high contact resistance) and/or attract dust and dirt thereby detracting from the product's appearance and, worse still, reducing its Surface Insulation Resistance (SIR) - which may well cause longer term functional problems.
It must be remembered that RMA fluxes are used on a wide range of products, with an equally large range of solders and process conditions; therefore each case must be considered on its own merits. For further guidance see TWI Soldering Best Practice Guide or contact micro@twi.co.uk
Reference
BS EN 29454 Soft soldering fluxes. Classification and requirements
