Hi all
I've read that isopropanol is a good choice to clean up the board after the soldering is done.
I've tried it with my second ever pcb.
The result wasn't satisfying at all.
After I brushed some 99.9% isopropanol on the back of the board a sticky white patina formed.
I've tried to clean the mess using a polishing cloth.
The result is in the picture.
I'm not satisfyied at all.
What's the problem?
Cheers
First, it depends on the flux used. There is no-clean, solvent-clean and water soluble. If you really need to clean the board, then use water soluble flux (WS) and just wash in water, maybe with a little gentle scrubbing with a toothbrush.
If you use one of the other fluxes, then it can be difficult. There are flux remover preparations that have a variety of stuff to break down and hold the flux in suspension. One was roughly equal parts of isopropyl, ethanol and ethyl acetate.
But, what I do for the non-WS flux is use plenty of alcohol, let it soak in for a minute, then brush with a toothbrush for about one minute, and immediately rinse with lots of water. You will see the alcohol turn white when the water hits it, that is the flux residue dropping out of solution. You need to wash it away as rapidly as you can, before it deposits back onto the board. Depending on the required level of cleanliness, one or two cycles of this process should get the board pretty clean.
For ordinary digital boards, I use no-clean flux and don't clean the boards. For critical stuff like high-impedance or high voltage circuits, I use either solvent clean or water soluble.
Jon