meech151 

Quick question about flux removal. I use Gas Flux brand fluxes on my frames along with the Gas Flux liquid system mainly because that is the way I was taught and haven't tried other brands. Their fluxes are supposed to wash off with warm water and most of it does, the silver-brazing flux always comes off easy but the flux that I use for brass/bronze always seems to leave a few hard spots that I have to file off or chip off, mainly around the BB shell. I imagine its from the heat but it is not burned up, just clear and hardened like ice. Any advice out there, any solutions to use that work well? I don't have a soaking tank, only a large sink or bathtub, but I would get one if it would make a difference.

JohnDThompson 

Are you using the "Type B" paste flux? This should come off with hot water -- the hotter the better. Anything that sticks should come off with a little scrubbing from a wire brush.

sannerbikes700

A 24 hour soak in soapy cold water tank works for me, then a bead blast. Hot water is probably quicker and easier though. I prefer Allstate #1113 paste because it seems to wash off a bit better.

meech151 

Thanks for the info guys. I will look into the Allstate paste.

sannerbikes700

Allstate isn't that much easier to remove than the Gasflux, just a little. But give it a try, it's a bit cheaper too... and it smells like some sort of yummy fruit pie.

Have you tried a high speed wire wheel (like on a die grinder) to get those stubborn globs off?

Nessism

Soak over night is what I recommend. Using a heater in the water is also good. Flux is acid and needs to be removed. Those hard chunks on the outside the tubes are also inside the tubes as well (too a lesser extent of course) so mechanical flux removal from the outside is not good enough - you need water to get inside the tubes to get all that stuff off otherwise you can have corrosion attacking the joints from the inside out.