Solder, wither art thou?

I'm still using my long expired free sample of solder paste from kester.

That is one good thing about solder paste; take good care of it and it seems to last 2-4 times longer than stated shelf life. That is one reason i get it in syringe or cartridge form, as the most that gets contaminated fro oxygen is the small amount in the small tube; jars are very bad this way and so are practical only when very large amounts are used out of a jar each time (say 1/3 or more).

What's wrong with no-clean? I like it. But I never use lead-free unless I really have to.

No-clean leaves terrible conductive and hydrophilic (I think) residue that is VERY hard to remove, even with solvent and vigorous scrubbing.

If all your stuff is digital or very low-Z, then maybe you won't notice it. But if you deal with nA, uV and such like (or rather accurate measuring circuits at uA/mV) you will get bitten, IME.

Best regards, Spehro Pefhany

Because it is verrrry hard to clean all of the sh*t off! I think that the so-called "no-clean" formulations are rather conductive, spread like crazy, and polluting and need semi-aggressive cleaners to remove..and need multi-level cleaning methods and more time and energy than water soluble fluxes.

When one wants to have their circuit to work reliably to 200C (not a misprint), then everything, meaning all parts: under, over and around, as well as all of the PCB *must* be clean.

add to the hi-z, hi temp: 200C!

That's why it's called no-clean! :)

I've never had any trouble with it, analog circuits included.

Hmm, three experienced posters had conductivity trouble with this solder and you and I never did. That's really strange. And I did solder rather sensitive stuff with it such as photodiode circuitry where nanoamps mattered.

Just for the record I use the 15mil Kester 8806 No-Clean (leaded) in my lab and also at many clients.

Ok, my stuff doesn't run that hot :-)

Might be they've changed the formulation or something, but I had conversations with the top technical people at the flux supplier at the time and they were unwilling or unable to make even informal assurances that their product would not cause problems, so we don't use no-clean at all. The guys making PC motherboards wouldn't care at all, and those guys are the customers they care about, so we folks with high accuracy (DC) analog have to be careful... I've never had a problem with good old Kester 44, even if imperfectly cleaned.

Might not have affected the AC signals.

Not for long anyway. ;-)

So far I never had problems with any solder, even the really old stuff I still have from when I was a kid, way back in the last century.

This was DC. Had to hold a level inside a loop and any DC-drift would have caused the gear to migrate away from an optical reflection position. But it never did.

Yep, the diodes and transistors would probably have croaked ;-)

I guess your stuff does not go into oilwell logging environments...

No, not the recent stuff. But it does go into Siberian type climate zones. So no electrolytics and so forth.

Must be catheters for Demonicratic politicians. No one else has a heart that cold.

:-)

I meant the other stuff I do. I am slowly migrating towards markets other than med, mainly because you can't buy PL insurance in the US anymore if you do med. Sad, but that's how it is.

Of course there'll be another big med project next year, these guys all have a lasso and don't let me escape.

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The key to removing many (not all) no-clean fluxes is water-alcohol=20 solvent with some added weak acid (lemon juice).

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=46rom what i have read over the past decade, no-clean was a bad joke. It never worked all that well. Must have been something an MBA thought = up. Give me rosin or water soluble and a nice cleaning process any day.

What kinds of problems do you have with no-clean? I use Kester No-Clean since years, no issues at all. Recently indroduced it at a client and they really liked it. If it only came in a smaller size than 0.015" ...

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thought up.

I only tried it once. It introduced leakage paths that i found = unacceptable. It wasn't convenient to remove either.