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Isopropyl vs denatured alcohol

Haven’t been online recently. Will be soon.

Anyway, for PCB cleaning like water damage, would denatured alcohol work instead of isopropyl alcohol? Reason being, isopropyl alcohol is pretty expensive, (1 gallon, $14, $28 shipping) and my physics teacher said isopropyl and denatured alcohol all really the same thing for most uses. @pccheese doubts this, and said I should ask here first. If so, what type of denatured alcohol should I look for?

@mayer @oldturkey03 @danj

Planning to run by my local ACE hardware store.

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@pccheese is right again :-))

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@captainsnowball You should include in the question what you're going to use the alcohol on and how you're going to use it.

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70% isopropyl alcohol for disinfectanting surfaces.

100% isopropyl alcohol for cleaning electronics.

Isopropyl alcohol dissolves a wide range of non-polar compounds. It also evaporates quickly, leaves nearly zero oil traces, compared to ethanol, and is relatively non-toxic, compared to alternative solvents. Thus, it is used widely as a solvent and as a cleaning fluid, especially for dissolving oils.

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@captainsnowball 70% IPA still contains 30% water. So you may add water to an already water damaged board. Don't use it!

Isopropyl alcohol has good solvating characteristics for removal of fluxes, ionic contaminants, residues, organics, oils, greases, fingerprints, water, and particulates. It removes moisture to submicron levels specifically in the higher percentage ranges (hydrophilic properties) . I use nothing less than 91% (Walmart ~$2.50) but prefer my 99% from TrueValue Hardware

Denatured alcohol is actual ethanol (C2H6O)that has added substances to make it inedible :-J. Those substances can be kerosene, acetone, turpentine or naphtha (and yes even isopropyl alcohol (C3H8O)) etc. and thus not something you want to use to clean your board of water damage. Let your teacher know that the distinction here is that denatured alcohol is a process whereas isopropyl alcohol is a product.

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We use denatured alchohol is woodworking all the time. I'm surprised to learn it's ethonal.

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Thanks for the tips guys! I’m accepting this answer over others as it directly answers the question at hand.

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@oldturkey03 I managed to get a half full 16oz bottle of 91% isopropyl alcohol. One thing though. It expired 12/17 does that expiration really mean anything? I imagine its hard for bacteria to grow in a bottle of antiseptic.

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@captainsnowball no worries. The alcohol won't know it has expired :-)

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Hi! I was wondering if denatured alcohol with a mix of 65% Ethanol and 35% Isopropyl, would be a better option for this case (or cleaning circuits boards in general) than having denatured alcohol made with any of the other options you listed? this is what I've been using lately without problems, but now I'm afraid it's wrong...

Thank you in advance!

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I use methanol which has no water in it. Yes, it is somewhat expensive, but a gallon will last me for three years or longer. I also use it for glued in battery removal.

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So should I look for methanol? Or is it under a different name?

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It's also called Methyl Alcohol

https://en.wikipedia.org/wiki/Methanol

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IPA is great for cleaning pcb's but the good stuff can be quite expensive. The other option is to get actual flux remover, such as this stuff: MicroCare Flux Remover. This stuff is better than IPA for removing flux. There are different brands and these can usually be found in electronic stores or can probably be ordered online too.

From what I read, denatured alcohol should work for flux removal but I have never tried it myself.

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I have a tiny bit of 70% isopropyl left, is 70% fine or will that cause issues?

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It leaves more residue...

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So not ideal?

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Do make sure you have a well ventilated room as breathing any solvent vapors can hurt you!!

Depending on what was spilled I tend to use distilled water as it can neutralize the acids and dissolve the sugars faster. While it sounds odd given the fact the phone or system may have had a bottle of water spilled into it with tap or spring water. Tap & spring water are full of minerals which is what harms your electronics! Distilled water is not conductive and won't corrode parts. I sometimes use an ultrasonic cleaner to speed things up and get into the areas I can't reach. I try not to use a brush so much and the newer boards its becoming more important as the SMT components are getting smaller! So its very easy to snag them without realizing.

I mostly use 90% isopropyl as it has less water than the lower grades and is classified as reagent so it doesn't have the other junk some isopropyl alcohols have.

The tip from Mayer pointed me to with methanol for releasing the batteries is a good one! But, you do need to be careful as some plastics react to it!

Flux remover sprays often have toluene in them which will kill your liver if you breathe it to long and often!

I visited a PCB house many years ago, they use distilled water and a citrus based cleaner for cleaning their boards and then air drys them, this is what they use when soldering of the SMT components. It showed me not to be fearful of distilled water.

Prove to your self get a pair of clean glasses and two nails as probes held in place across from each other in the glass to hook up to an ohm meter to put some tap or spring water into one glass and distilled water in the other measure the resistance you'll see the distill water will have the most. To add to this sprinkle some table salt into the glass with distilled water it won't take much for it to become conductive!

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With distilled water, if I were to touch it, would the natural oils/paricles make it conductive?

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The only thing would be the salt in your sweat. I wear gloves so that or oils are not an issue. Besides we're washing away the contaminants of was spilled.

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One thing I have not seen mentioned in this discussion (or maybe I missed it?) is the difference between medical grade and electronics grade 99.9% isopropyl alcohol. Today on Amazon I see a medical grade product for $13.99 per quart and an electronics grade product for $20.77 per quart. Is there any reason why I would be better off with the electronics grade product for cleaning PCBs etc or should I just purchase the less expensive medical grade product?

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@dtg - Here's a deeper look at the different grades of chemicals Demystifying Material Grades for Your Laboratory

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Thanks for the link. But that article did not demystify anything at all for me so I will reframe my question: "Do you use only electronics grade isopropyl, or do you (or would you) use a less expensive medical grade isopropyl, assuming that both are a sufficiently high percentage (99.9% in this case)?

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Isopropyl alcohol at 99% has the advantage of not leaving deposits on the pcb, disorders can appear especially at high and very high frequency because of these deposits.

Otherwise, denatured alcohol or the like should not be critical.

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I don’t know if someone would agree to me but here in my location, my best option for cleaning PCB’s is only Denatured alcohol. It seems like it works for me. I have a lot of broken boards that has been repaired using this alcohol. I even use it to remove rust from my DDR3 RAM’s pins. It’s kinda old so it has rusts. I know it’s cheap but here in my location, everything is expensive so I can’t afford 99% isopropyl alcohol. Denatured alcohol is only about 25-40 ph pesos per bottle in local hardware. (roughly 0.50 USD) and everything that I repaired using Denatured alcohol is still working. I also research a lot about this alcohol but it seems like there’s no one have answers like can it be used in electronics, repairs, etc. I can’t even find an alcohol percentage of denatured bottle so I just tried it out and it works fine untill now. Hope it helps and somebody gets an attention with this. Maybe we could actually replace or have an alternatives for isopropyl alcohol.

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Vherniel Lebis if it works for you and if your boards do not desolve or shorten out, you'll be okay with it. I am just a proponent of at least a 90%isopropyl alcohol.

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Okay, thank you. I'm just gonna make sure it's dry before I will try to test the PCB. It is also great to dissolve some adhesives too!

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Hey, I would suggest that you DO not use denatured alcohol for cleaning any electronics. Denatured alcohol will leave behind a residue that will DAMAGE electronics. Use Isopropyl alcohol the cheap stuff from the pharmacy.

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Well, our local pharmacy and even big pharmacies don't have 99% alcohol. They only sell 70% below. While denatured is easily bought in local hardware stores.

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Vherniel - See if they sell Grain Alcohol 85% Being the best!

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Denatured alcohol which is ethyl alcohol can be denatured in dozens of different ways. It used to have benzine in it and has to have some type of chemical that will be a deterrent to drinking it. It is moonshine. If it is hydrogonized, which is the cheapest way to go it will have methanol and Pyridine.Pyridine is used as a polar, basic, low-reactive solvent. I’ve repaired guidance systems and nukes themselves and we used nothing but Denatured Alcohol. Isopropyl alcohol even at 99%; the water would need to be deionized and demineralized, And that would be expensive. Just my $.02.

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I find it very unlikely that someone that has even came close to a nuke would post about it on the web. But yeah, I've washed my mobos with 70% ethanol my whole life, with at least 24h in hot days and 48h in cloudy days for open air drying.

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In Brazil we have a long history of Ethanol production, most cars run on both gas and ethanol or any combination of the two, our “rubbing” alcohol and hand sanitizer gel are all made with ethanol. I haven’t even heard of isopropyl until about 15 years ago. Have been washing motherboards with supermarket 70% ethanol my whole life. The only caveat is waiting at least 24h in hot days and 48h in cloudy days for open air drying (leaning against the wall in a corner somewhere).

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Both are useful.

You are right about Ethanol, it is widely used in laboratories.

Isopropyl (IPA) is also used very strongly.

I invite you to read the analysis “ Ethanol vs Isopropyl”, which you will find at this link if you want to know more:

https://labproinc.com/blog/chemicals-and...

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IPA is the best for lot of features.

I use it.

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100% Isopropyl alcohol evaporates in seconds and leaves no oily residue.

If it doesn't evaporate quickly then it is probably 70%, commnonly used as a disinfectant. We used the 70% at the hospital I worked at.

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