Isopropyl Alcohol for Cleaning Flux

Even the quart size is overpriced. If you're willing to wait for a sale, you should pay no more than about $1 per pint.

I can just see a pitcher tossing a roll of solder at the batter.

91% IPA is not usually considered to be 'electronics grade', which should be 99.7% minimum. It's also not the most appropriate stuff for cleaning a lot of flux, which requires a proper defluxing agent such as Electrolube Deflux 160

Arfa

91 leaves a bit of residue in certain cases. After reading the ingredients on a can of Flux-Off spray flux stripper I thought why not just use 91 isoprop. It usually does work in conjunction with a toothbrush. But like I said can leave a residue.

On 7/26/2010 10:30 AM Meat Plow spake thus:

Why mess around with isopropyl alcohol at all, since all of it contains

*some* water? Use denatured alcohol (methanol) instead, in a tightly-capped container to guard against absorbing moisture.

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That would be fine if you used it in ZERO humidity. Its not worth the trouble using 99.99%

95% is a very good figure. I actually use the NON-denatured stuff. I don't buy it, but the medical labs buy it.. Its safer than 99% stuff due to dryers contamination as far as drinking. The The denatured stuff probably has more residue.

Seems to me methanol has the ability to harm some materials its used on.

I also have a 4L bottle of isoproypal 99.5% .001% residue which is nice. I will ALWAYS have water on the board after cleaning just from room humidity. I usually take a hot air gun or pistol to heat dry the board or put it under an incandesant light bulb.

A possible source for cleaning boards, gas tank alcohol, "dry gas" probably mostly isopropal alcohol, probably 98% or better.

greg

How about the drinking stuff? (95% "grain" alcohol).

Here I can by a "fifth" (750ml) for less than 250ml of 70% Isopropyl.

Geoff.

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Geoffrey S. Mendelson N3OWJ/4X1GM
To help restaurants, as part of the "stimulus package", everyone must order 
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On 7/26/2010 11:49 AM Geoffrey S. Mendelson spake thus:

Well, that's ethanol, which should also work fine, so long as you don't mind the 5% water.

--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

Yes I was reffering to the ethanol drinkable stuff that is not taxed. Been used for years in medical parties.

greg

For some strange reason, the cheapest booze you can buy in Israel is the

95% it costs about 25 NIS a fifth, around $6 INCLUDING TAXES.

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
To help restaurants, as part of the "stimulus package", everyone must order 
dessert. As part of the socialized health plan, you are forbidden to eat it. :-)

I use medical or denatured alcohol as a general-purpose cleaning solution. When I need stronger stuff, such as on cruds of old and hardened flux or when there's simply lots of it, I use automobile paint thinner. Wiping with a piece of cloth or cotton wool is usually enough and I rarely need to scrub with a brush.

The thinner can dissolve some plastics though. So some care is needed, as is good ventilation. It looks and feels somewhat oily but dries very quickly. A one-liter can costs about $3 US here.

I got some spray heavy duty flux remover with freon like component, methelyne chloride, ethanol, and another component. Its useless for regular cleaning. It dries too fast. I never had the need to use other than alcohol for flux remover. When I worked in a factory "DEC" in 1969, they had like washtubs with spigots, and turn on the spigot out poured "TRI", trichloroethane. It worked well. I still have a can around saying safety solvent. Sometimes we would try to fix their modules, for some forgotten reason, to fix a computer problem.

I also remember fellow in our section, working on something new, computer "terminal monitors". There was some kind of problem, and he was taking some boards into the mens room to wash them off. i guess they worked after that.That was an interesting section with monitors, modems, and UARTS, and the PDP 8i About 7 people.

I remember they used to sell cans about the size of paint sprays filled with trichloroethane , sold as fire extinguishers.

greg

Not a wise move. The un-taxed stuff (not for human consumption) often contains benzene.

Hope you never use it on a board that's got a lacquer type coating on it then ... :-\

What amazes me, and I can't understand, is why all of these 'substitute' chemicals are used by people, when the proper ones, designed for the job, are really not expensive in the first place

Arfa

Another question is why do they try to clean rosin with pure alcohol that is extremely ineffective for that purpose?

The ad-hoc solution that is cheap and works really well is a mix of 60% denaturated alcohol with 40% Xylene from a hardware store. Pure alcohol is a very bad solvent for rosin flux, very slow and leaving a lot of white residue.

And it only makes sense to invent something homebrew if very good flux remover in aerosol cans is really unavailable. Otherwise just go grab a can at your local Fry's (or whatever) and enjoy.

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Perhaps it is different where you live, but here in the US, denatured alcohol is not methanol; it is, instead, ethanol with a denaturant added. The denaturant can be methanol, or it can be any number of other chemicals, so long as it is sufficiently adulterated to prevent a person from using it for ingestion.

Jon

I do take care to use it only where it won't do damage. The "some plastics" was just an example.

Some people use the substitutes because they don't know better. Others have good reasons: The "proper" ones are not easily available in many parts of the world, including mine. And the thinner serves other useful purposes too. It's a good general-purpose solvent.

Yes, the fact that it's not very good for some types of flux - rosin as you say - was one of my original points. Alcohol is fine for cleaning general crud and sticky things and greasy things, and I keep a can of Electrolube

99.7% electronics grade IPA for just those purposes, but I also keep a can of proper defluxer for, well .... defluxing ....

Arfa

"using it for ingestion" = "drinking it" You will soon be visited by Jacques Barzun and put to death in a most unpleasant manner.

Methanol is wood alcohol. It _is_ drinkable -- but poisonous. Among other things, it causes blindness.

I've never tasted denatured alcohol -- a few drops are harmless -- so I don't understand why denatured alcohol is "undrinkable".

Thats the 99% stuff that contains benzene.

greg