DocStein99:
I am still using up the stacked tins in my father's cabinet, this green toothpaste/waxy stuff that's made from anyone's guess. I have to heat it over a flame, suck it up with a syringe because it's so thick.
I would wager that it is acid flux.
aarg:
I would wager that it is acid flux.
I can assure you it IS acid flux solder paste made to smear on copper pipes before soldering them together. It replaces the lengthy process of cleaning the copper, putting flux on the copper pieces, pressing the joint togther, heating with a flame and adding solder so it will wick into the joint.
I have some of the stuff in my loft, too. Left over from years ago.
Paul
Paul_KD7HB:
Actually, Mark, all the liquid fluxes, except rosin, are organic acids that are activated by the heat of soldering. That includes the flux in solder paste used for SMD. That is why ALL the boards must be washed clean soon after soldering.The flux is designed to be neutralized by the soldering heat held for long enough complete the soldering operation. Even "no clean" solder paste must be used with minimum amounts necessary so the flux will be all converted to non-acid.
Ah, I meant the inorganic acid fluxes - those are strong acids and damage boards. Organic compounds
don't leave salt/ionic residue that rots things. I think they try to use water soluable fluxes to reduce
costs and solvent use in production setups.
I remember during WWII, or soon after, my father made soldering flux using HCL to dissolve zinc. I am sure that would rot copper if left too long.
Paul
That's called 'killed flux' in the UK. It's still corrosive, and hasn't been used for years. Useful if you want to tin steel for any reason.
Allan
My KESTER liquid flux arrived today, there are two bottles:
186, and 951. 951 is clear, labeled "ROSIN FREE". Two bottles, 2 ounces is $10.00. 1 pound of rosin (doing a quick search) is $9.00, added with the alcohol thinner would probably would have given me over a year's worth.
After I stop being lazy and covert the solid stuff I have with these two bottles of kester, I can say what I see a difference would be - if anything, but unable to predict what 10 years of corrosion on a pcb would do (or at least until someone helps me with schematic for time machine flux-capacitor circuit).
If you're so worried about flux corrosion, why not get a small horsehair brush and clean the board with isopropyl alchohol after soldering? I use 99.9% from the electronics distributors, dries very quick, much better than the 79% or 95% or whatever the drugstores carry.
CrossRoads:
If you're so worried about flux corrosion, why not get a small horsehair brush and clean the board with isopropyl alchohol after soldering? I use 99.9% from the electronics distributors, dries very quick, much better than the 79% or 95% or whatever the drugstores carry.
Agree.
While the board is still wet with the alcohol, rinse with distilled water to get rid of all alcohol and the dissolved flux.
I find this cleans the board completely.
.
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What about mineral spirits? I use that stuff to clean practically everything. The Radio Shack around me closed, since they could no longer sell iPhones for $1,000 anymore, so I would have to special order isopropyl.
The corrosion does not bother me, really I would be using this for de-soldering good stuff from scrap. Any of my circuit boards never usually make it to 6 months of use, so unless it corrodes within this year I'm good.
DocStein99:
What about mineral spirits? I use that stuff to clean practically everything. The Radio Shack around me closed, since they could no longer sell iPhones for $1,000 anymore, so I would have to special order isopropyl.The corrosion does not bother me, really I would be using this for de-soldering good stuff from scrap. Any of my circuit boards never usually make it to 6 months of use, so unless it corrodes within this year I'm good.
You will never be able to get that stuff completely off the components or out from under the components, or out of the connectors.
We use the cheap drug store IPA and have for over 15 years and it works just fine! I have 5 gallons of 100% IPA, years ago we used that to dilute the flux tank in the wave solder machine. The cheep stuff will work just fine for you, also.
Paul
Something you need to consider in your solvent choice is whether it will damage the plastic on components.
