Isopropyl Alcohol for Cleaning Flux

Right. Methanol is a very poor denaturant. The idea is to make it undrinkable, not lethal. Someone ralfing their guts out for an hour is cheaper than blindness or death. Now, Sterno...

The treatment for Methanol poisoning is Ethanol and lots of it. Usually by IV.

tm

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AIUI, this swamps the liver so it doesn't produce as much formaldehyde at once.

Yup. Recipies for denaturing ethanol seem to vary a lot by country and by intended application of the denatured alcohol.

lists a bunch of different formulas that are specifically defined and authorized in the U.S. for certain applications. Some of them seem downright scary:

Formula 2-C: To every 100 gallons of alcohol add thirty-three pounds or more of metallic sodium and either 1/2 gallon of benzene, 1/2 gallon of toluene, or 1/2 gallon of rubber hydrocarbon solvent.

5 gallons of methanol per 100 gallons of ethanol is Formula 3-A.

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Dave Platt                                    AE6EO
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The same treatment is also used at times in cases of poisoning due to ethylene glycol (antifreeze). If I recall correctly, the idea is to saturate the liver's conversion-enzyme system with ethanol, thus blocking the breakdown of methanol or glycol into toxic byproducts.

--
Dave Platt                                    AE6EO
Friends of Jade Warrior home page:  http://www.radagast.org/jade-warrior
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None of the 95%.

I wouldn't bet my life on it.

Long ago (1980?) I remember having problems with leakage on a board that stored voltages in polystyrene capacitors using CMOS switches and op-amps, but the voltage would bleed off too quickly to be useful as a "memory". We tried all sorts of flux removers and it still didn't work well enough. But I had an idea that it might be ionic contaminants such as salt, so I took a board into the mens room and scrubbed it with hand soap and flushed it with hot water. Then I dried it with a heat gun, and "voila" it worked like a champ rather than a chump.

I have had good results with isopropyl alcohol as a flux remover, applied with a stiff "acid" brush with bristles cut short. It does leave a white residue. But then I follow with a spray of detergent, scrubbing once again, and the heat gun to dry it thoroughly. You need to be careful about overheating, so I hold the board by hand on the edges and move the hot air around. My fingers will hurt before I overheat the board. Seems to work very well.

Paul

Interesting observation.

Question... Wouldn't distilled water alone flush off ionic contaminants?

Probably. But there may be some sort of oily residue that will be removed by the detergent. And hot water from the tap is much cheaper. It may be good to do a final rinse with distilled or deionized water. I have heard that some people stack their boards in a dishwasher. But my method works for me and is is very practical for small quantities.

Paul

We used a citrus based cleaner in a commercial board washing machine at Microdyne. It was a modified stainless steel industrial dishwasher with a separate solvent tank and fresh water wash. Then the boards went into a board drying oven for 12 to 24 hours. This was for small runs of boards stuffed and reflow soldered in house.

I noticed citrus based degreasers leave behind oil. Thats a bad thing when you really want to paint something thinking it will work. Bad for tape sticking also.

I think I allready mentioned mens room board cleaning.

greg

Mention whatever you want, but it was a NASA approved process. We built telemetry equipment for the aerospace industry. NASA wouldn't approve of your method. We built millions of dollars worth of equipment per year.