We’ve talked before about how the pandemic has shown some serious strain on our global supply chains. Once upon a time it came for isopropyl alcohol. While IPA may not be hard to find, or triple the usual cost, we’ve still got the details, and alternatives, right here for you.
We know, rely on, and recommend isopropyl alcohol (a.k.a. isopropanol, or IPA) for many of our techniques and guides. It’s pretty simple stuff, but it is sold in different ways, and recommended for a myriad of uses.
Understandably, people have questions. Is “rubbing alcohol” or “surgical spirit” the same thing? What percentage of isopropyl do I need for electronics work or disinfecting? Can I use anything else on my electronics? And, hey, is this stuff going to catch on fire if I cause a spark?
Let’s clean up these questions.
What Is Isopropyl Alcohol? How Is It Made?
Isopropyl alcohol is a clear chemical that is flammable. It smells a bit like vodka or other spirits, just without any kind of scent other than alcohol. Manufacturers make it by adding water to propene (itself steamed and heated out of propane and other hydrocarbons), then distilling the mixture to a desired strength, similar to how liquor is made.
It’s usually sold in a few set percentages of alcohol-to-water: 70% and 90/91% are most common, but you’ll sometimes see 60% or, at hardware and specialty supply stores, 95-99%.
Why Do You Recommend Isopropyl Alcohol for Cleaning Electronics and Removing Adhesive?
It’s widely available (at least in non-crisis times), it’s relatively inexpensive, and it does a few important jobs at once. Isopropyl:
- Dissolves oils, adhesives, soldering flux, residues, fingerprints, and other contaminants
- Leaves no oils or traces, unlike many ethanol compounds
- Evaporates quickly (at least in spaces above 60 degrees Fahrenheit)
- Is relatively non-toxic, assuming you’re working in a decently ventilated area
- Disinfects viruses and bacteria (at concentrations of 60/70 percent)
- Mixes with water fully and then evaporates with it, making it the best way to remove and prevent corrosion damage from liquid spills on electronics.
I Can Only Find 70% Isopropyl Alcohol. Can I Use It to Clean My Devices?
It’s best to avoid using any isopropyl mixture below 90% on circuit boards and other electrical bits. If you’re simply cleaning the adhesive off something metal or plastic, 70% might do in a pinch, but you’ll want to be sure not to spill it onto circuits or wires. There’s enough water in that lower-grade stuff that it will take longer to evaporate, and may leave behind trace impurities from the water when you’re finished.
90% works fine for most purposes. 99% might be technically optimal, but it’s trickier to find in some places. Grab a bottle when you can find it, but don’t worry too much about the last 10%.
What About Other Compounds that Have High Alcohol Percentages? Nail Polish Remover?
We suggest you stick to something you know and has known ingredients: isopropyl alcohol and water. Rubbing alcohol, denatured alcohol, surgical spirits, and other high-alcohol solutions often contain other chemicals, scents, or other substances that have different properties than IPA, or are a bad idea around boards and wires. If the package doesn’t have isopropyl alcohol as the only active ingredient, and water as the only inactive, it might be best to hold out.
This is especially true for nail polish remover, or acetone. Acetone is a stronger adhesive remover than isopropyl alcohol, at least for the kinds of adhesives often used in electronics. But acetone also damages ABS plastics, the most common in electronics. That’s why we include just a little acetone in our adhesive remover, to make it even more effective, but not so much that it will melt plastics, presuming you wipe it up fairly quickly.
What About Vodka?
Most vodka, and most liquor generally, is around 40% alcohol by volume, so no, it’s a bad idea for electronics repairs.
But I’ve Got This Booze That’s Really High-Proof.
You’re better off saving that for large batches of party punch, given the cost. Ethanol/ethyl alcohol is not the same thing as isopropyl alcohol, either.
Will Isopropyl Damage My Screen? My Laptop Keys? Other Things Inside My Device?
We’ll only tell you to use isopropyl alcohol on surfaces where it’s safe to do so in our guides. And we try to warn you when spills or an abundance of liquid can cause damage. In our guide to replacing the battery in a 2013 15-inch MacBook Pro, we note that our own adhesive remover (the majority of which is isopropanol, but also a small amount of acetone) can damage the anti-glare coating on your display, and the plastic on the embedded speakers.
Generally, metal and circuit boards don’t have a problem with adhesive remover, but you should be cautious around display components (especially the LCD or OLED backing behind a screen), plastics, and, obviously, anything that is glued together that you want to stay glued together. Generally, a cautious approach is best; even better is a little pre-fix research. Electronics cleaning vendor Techspray has a material-by-material list of what reacts to isopropyl alcohol. If you’re not sure, don’t put a bunch of alcohol on it (a good general rule for life, you might find).
We recommend isopropyl alcohol as one of the steps to cleaning out your keyboard. But note that we recommend a damp towel, not pouring the stuff straight on.
Many device makers are clarifying what is safe to wipe with sanitizing solutions. Microsoft says you can clean the felt-like Alcantara cloth on its Surface products with a 70% alcohol solution. Apple used to suggest that you had to be really careful around its screens to avoid removing the oleophobic coating, but now using a 70% solution is at the top of the official “Cleaning your iPhone” page. Searching for cleaning or maintenance instructions for your device is a good place to start.
It’s Flammable Stuff, with a Poison Warning Label On It. How Concerned Should I Be?
Nearly every iFixit guide is built around getting to the battery and disconnecting it before you do any work that would put you in contact with electrical circuits. Once the battery is disconnected (or you’ve unplugged the device, if it lacks a battery), your chance of accidentally creating a spark, or exposing isopropyl to heat, is much reduced. Electrostatic discharge from your clothing or rugs is quite unlikely to cause a fire, but it’s always a good idea to avoid it. The main thing you want to look for, then, is larger capacitors in bigger devices, which can store a charge even after disconnection from power. For most repairs, this isn’t an issue.
Regardless of the use, you should treat isopropyl alcohol like any other flammable substance with strong vapors in your house. Don’t expose it to flame or high heat or sparks. Keep it tightly closed when not in use (this also prevents wasteful evaporation). And don’t use it in enclosed spaces with poor ventilation.
A big thanks to Old Turkey, Mayer, and other iFixit Answers VIPs who laid out a lot of this knowledge. Got any more questions about isopropyl alcohol, or anything else repair-related? You can help us decide what to tackle next. Ask us in the comments, or tag us on social media with #AskiFixit.
crwdns2944067:040crwdne2944067:0
99% ISO is (when not in a time of crisis) available from Amazon. You can get 90-93% from most pharmacies and big-box stores, but the only retail store I ever found selling 99% has been Safeway (the grocery store chain).
But that’s for cleaning electronics. If you want to use it to sterilize a surface, you’re better off with 70%. It requires a certain amount of water in order to open a bacteria’s pores, so the alcohol can quickly get in and kill the pathogen. The sterilization process takes significantly longer with 90+%.
shamino - crwdns2934203:0crwdne2934203:0
I was going to say essentially the same thing about 70%. The reason why it’s so popular as a disinfectant is that it is the optimal percentage for sterilization as determined by medical tests done way back in the 1920s when it was first synthesized
Bill Hudson -
As a computer repair instructor I advocate 99% for most cleaning situations. I begin the safety portion with MSDS(SDS now) of the respective alcohol solutions, followed with a safety test AND ALWAYS wear protective devices: glasses and gloves(latex, latex free…). Even wiping surfaces with a towel/rag my students follow protective practices as well as disposal. I did the same activities for my own business. T. Weed
tweed - crwdns2934203:0crwdne2934203:0
Fujitsu recommends using 99% to clean their scanners (including the rollers), and I have used it to clean other scanners and their rollers as well. What I have found is if you put your solvents in a plastic squeeze bottle (Harbor freight sell a pack of 3 8 oz bottles with caps for $2.99). That way, you can put the solvent where you want it (or squeeze it out on a cloth), recap the bottle, and not waste any.
Steve J - crwdns2934203:0crwdne2934203:0
So right as everything was going !&&* I picked up some 91% at the pharmacy. what is the ratio of water to add, to turn the 91% into 70%?
For Example - I put two ounces of the 91 in a bottle how many ounces of water to add to dilute it to 70%?
Thanks.
Jeff Goodstein - crwdns2934203:0crwdne2934203:0
I did this with some 91% isopropyl and aloe vera gel. I had about 10oz. which could be taken as 9.1 oz. of pure alcohol (100%) - round to 9 oz for doing the math. Since I didn’t want to go too dilute, I put in only 3 oz. of the gel - thats 3 parts alcohol, 1 part gel, the final ratio of alcohol to mixture is 3/(3+1) = 3/4, or 75%. I never did figure out a nice formula for calculating exact amounts to hit a specific dilution, I figured the 75% was erring on the conservative side so I wouldn’t over dilute. I suppose you could use actual ounces, like 9/(9+3)=0.75, and then wiggle the 3 up a bit, such as 9/(9+4) which is 0.69
Joel -
If two ounces of 91% has 2 x .91 = 1.82 oz of alcohol, and you want that same amount of alcohol to be in a 70% dilution, the total volume must be 1.82 / .7 = 2.6 total ounces. The 30% water content must be 2.6 x .3 = .78 oz. Since the original dilution has .18 oz, you add the difference of .78 - .18 = .6 oz to get the correct 70% dilution.
raymondjram -
do the math: answer, anywhere between 11cc to 999cc should work.
John Harvey -
You will need to add .3 oz of water to each ounce of 91% solution to dilute it to 70%.
91 / .7 = 130
130 - 100 = 30
30 / 100 = .3
William Chundak -
Add 0.6 ounces water for a total of 2.6 ounces of solution to get a 70% concentration of IPA.
ALAN HOM -
2 ounces of 91% isopropyl alcohol has 2.0 * 0.91 = 1.82 ounces pure alcohol.
With the 1.82 ounces of alcohol, a 70% solution would be 1.82 / 0.70 = 2.60 total ounces.
So you need to add 0.6 ounces of water to your 2 ounces of 91% isopropyl.
(1 fluid ounce is 6 teaspoons, so 0.6 ounces is 3.6 teaspoons.
If you use 3 teaspoons of water, than that’s half an ounce, and your concentration will 1.82/2.5 = 73%)
David Iwatsuki -
0.91×2oz=0.70×(2oz + Xoz)
Andrew -
Let’s use a milliliter (mL) as the measure as its based on a better unit of measure. So if I have a container of 1000 mL (one liter) then 910 mL of it is isopropyl alcohol to dilute it down, let’s say 70% a 1000 mL container would be 700 mL isopropyl alcohol.
So subtracting 700 from 910 give us a difference of 210 so adding 210 mL of water to a container which is holding 700 mL of 91% isopropyl alcohol will get you down to 70% isopropyl alcohol.
As milliliter (mL) is a ratio measure within the metric standard we can scale it up or down! So I could use the same method with liters! 100 liters Or work on smaller measures of milliliter (mL). So instead 1000 mL which is what one liter equals to) we can do 500 ml or half a liter ( .5 liters) or even 100 mL
Which is why the metric system is so much better than the english measure!
Dan -
What you want to do is…. Never ever think about that question ever again. I can’t imaging why you would need 70 over 90+ for any reasonably thought out purposes when using it as a tool for repairs. 70% can cause the same damage to coating that 90 % causes if you let it sit in one place and then go have dinner. Other than that there is no kind of benefit to having 70 over 90 when they both cost like 5 dollars a gallon basically anywhere drugs are prescribed
James Sassu -
I was able to order a gallon of 99% Iso from a company in Florida and they shipped it in (4) 1Qt containers. Very handy as I had been planning to use my own smaller containers.
JonnyLotto - crwdns2934203:0crwdne2934203:0
if used as a hand sanitizer diluted down to 70% with either water, or with (as I did, to make the solution less irritable to my skin) aloe vera gel, then 1 gallon of 99% will last you a very, very long time!!!!
I used 10 oz. of 91% and 3 oz. of aloe vera gel to obtain a 75% by volume mixture, and it works great!
Joel -
2 ounces of 91%, let’s call it 90% for ease of calculation. That is 0.2 ounces water, 1.8 ounces iso. To get 70%, you need to make 1.8 ounces of iso 70% and X ounces of water 30%. So just look on them as ratios.
X/1.8 = 30/70
X = 0.77 ounces
You already have 0.2 ounces, so 0.57 ounces or approximately 0.6 ounces.
Steven J Greenfield - crwdns2934203:0crwdne2934203:0
Your reply was rounded out. My reply has the exact amount.
raymondjram -
Always keep a large, heavy towel handy in case of fire - when alcohol is ignited, it’s nearly impossible to see the flame in a well-lit environment. Use a heavy towel to smother the work area and/or your hands in case of ignition. Stay safe everyone!
John Grzeskowiak - crwdns2934203:0crwdne2934203:0
Bravo for this subject matter! Long overdue!
In our computer repair shop, we never used anything other than industrial grade 99% PureTronics Isopropyl. Why risk even 5-7% water in a mixture? We cleaned logic boards & all parts with this, but you’re right about being cautious on screens. They like a more detergent-based cleaner (a Windex-type product).
It’s interesting to note that alcohol-based cleaners sometimes simply do not so the same as the detergent-based ones. We often used the foaming SprayAway Glass Cleaner you can get at Costco (in packs of 4, of course). We used that w/great success on most of the screens as well as the clamshell of Mac Laptops.
Lastly, there’s Goo-Gone, or the one I think is better De-Solv-it. That’s excellent for getting ugly, gummy stickers off people’s MacBooks and making them look new again.
Best cleaning rags are quilted English diapers. Super soft, gentle, & with the SprayAway, always best to spray on the rag first, then clean.
Now you know all of my industry secrets.
Mick - crwdns2934203:0crwdne2934203:0
Do you want to clean electronics, or sanitize your phone? Remember, you need 90% or higher for electronics. But, if you take 2 ounces of the 91% alcohol, and add 2 ounces of water, you will have 4 ounces of 45.5% alcohol; if you were to add only 1 ounce, you would end up with 3 ounces of 60.67% solution. Two-thirds of the 3 ounces is 91% alcohol. On your calculator, you punch in (2/3)91% =60.66666667
I hope this helps.
jimmy5 - crwdns2934203:0crwdne2934203:0
70% ethanol has been found to be most effective in killing microbes. Higher or lower concentrations are not as effective in killing microbes. The alcohol goes into the cell wall. 90% evaporates too quickly and can not totally penetrate into the cell. 70% isopropyl goes thru the cell wall and into the cell.
gredmore - crwdns2934203:0crwdne2934203:0
I have been able to order 99% from my pharmacy, a major chain. It was about $4.50 per pint pre-covid. Best of all I did not have to pay for hazmat shipping. One time I ordered some from McMaster and shipping cost more than the gallon of IPA, had many restrictions.
Collin - crwdns2934203:0crwdne2934203:0
The thermal paste got stuck to side pins of my cpu as we can wipe the pins can we use drops of 99 alcohol on it to clean it.
bobba Satya Akarsh - crwdns2934203:0crwdne2934203:0
I use a reloadable stray bottle with a snorkel tube (one which uses an air compressor, not a built-in pump) I load it with isopropyl alcohol and the spray will clean out the stuck thermal paste between and under the SMT devices on the green CPU carrier.
Dan -
Removed a PCB from an a/c unit fitted in a coastal area. The PCB is contaminated with salt. How do I clean it.
Dawie Burger - crwdns2934203:0crwdne2934203:0
Brushing it clean with bristles dipped in 90%-99% isopropyl, like shown in the photo attached to this article, should work. You can also use an old toothbrush, if it’s a soft-bristle type. It may take a few passes to completely clean off all of the salt and other debris. Clean it off, let the alcohol dry, and see if there’s any sediment remaining on the board. (It’ll probably have dissolved in the alcohol, so anything left will be redeposited in puddle-like formations as the alcohol evaporates.) if you see any of those, clean off the bristles with soap and water, then do another pass.
Also, of utmost importance: BEWARE of electrical shock. AC units are a prime example of devices that contain a giant capacitor which will hold a charge long after being powered off / unplugged. (The other common example was any kind of CRT display, fortunately those are rarely serviced anymore.) The huge metal cylinder inside the AC (probably attached to the board, but possibly wired to it) is not your friend.
FeRD -
i dropped my phone in a toilet and it was there for ten minutes it wont turn on so i took it apart what should use to clean its circuits and stuuf
Crisean Dalomba - crwdns2934203:0crwdne2934203:0
Hi Crisean, I’m not sure what type of phone you have, but this guide has great directions you can apply to your phone.
Amber Taus -
I bought my alcohol by the gallon at home depot. Used to degrease before painting and for alcohol stoves. Around 90% to 99%. Don’t see it on the depot web site, but you can get it as stove fuel at Amazon or hardware stores. One gallon lasts a long time cleaning.
Jon - crwdns2934203:0crwdne2934203:0
That’s denatured alcohol.
Infographic
xsie -
I use 100% (probably really 99.999%) IPA. Always easy to get and works really well. Never had a problem with it on any phone or computer components.
David King - crwdns2934203:0crwdne2934203:0
You do understand that using isopropyl alcohol to clean any thing with printing on it (keyboards, cameras, etc.) the printing will be removed.
James Hickory - crwdns2934203:0crwdne2934203:0
Always thought IPA stood for India Pale Ale…
Mike Smith - crwdns2934203:0crwdne2934203:0
Mike, you are correct! The "golden" colored IPA should go in a frosted glass next to your work area, where as the clear IPA should remain in a sealed bottle until needed! I definitely recommend having the golden IPA available on any repair! ;)
Rob B.
Robert - crwdns2934203:0crwdne2934203:0
Has anyone mentioned that when performing the dilution of higher percentage IPA that you should probably use distilled water and not "tap" water? I can see if your just making a surface sanitizer where that wouldn't make a big difference, but in instances where your still working/cleaning anything electronic the "added" benefits of other minerals and such from tap water might leave some residue behind. i can get a gallon of distilled water at the grocer for $1.50.
Robert - crwdns2934203:0crwdne2934203:0
Where can I buy it on a British highstreet? Buying online is not possible for me.
Jake - crwdns2934203:0crwdne2934203:0
Ace Hardware regularly carries the 99% stuff.
Matthew Sahlgren - crwdns2934203:0crwdne2934203:0
Thanks for the very useful article. Two things not mentioned:
1. Even though, yes, isopropanol "evaporates quickly", at 82.6°C its boiling point is higher than ethanol's (78.23°C), and much higher than acetone's (56.08°C), so it causes less thermal stress to components by evaporative cooling. (Boiling points from Wikipedia.)
2. In most places, isopropanol is cheaper than the same grade of pure ethanol, because it's not subject to liquor excise tax. Yes, you can get "denatured alcohol" or "methylated spirits" cheaply, but is often not clear which deterrent bittering additives are used by the manufacturer.
Les Kitchen - crwdns2934203:0crwdne2934203:0
Would pre-injection swabs at 70& IPA ALCOHOL still have too much water content for cleaning solder and flux residue on pcb's?
Long
long - crwdns2934203:0crwdne2934203:0