[sdiy] cleaning flux

[Dave Manley]

Derek Holzer wrote:
> Would anybody like to take a stab at explaining why cleaning flux 
> might be necessary? I'd also never heard about it before this thread.
Some flux types are corrosive and by their very design require to be 
removed, for example Organic Acid types. 

Others are not, for example various 'no-clean' flux types.  These are 
supposed to be non-corrosive and non-conductive.

Flux only needs to be removed in a few circuits - those that have high 
impedance nodes, in synth circuits this mainly applies to sample/hold 
circuits where a charge is stored on a capacitor.  If flux is present, 
it might present a leakage path that will cause the held voltage to 
droop over time.

There are other exceptions, for example if the board is going to be 
conformal coated it is usually required to clean all residue from the 
board.  I doubt anyone is conformal coating their sdiy boards.  If you 
have ever had to rework a conformal coated board you know it is a total 
pain.

Personally, I think most people remove flux for aesthetic reasons.

-Dave