Where can I buy 99% isopropyl alcohol? - Page 1
Forum section: electronics / repair

author: Axtman
author_rank: Regular Contributor
timestamp: October 05, 2021, 05:07:47 pm
content: I have casually looked at a drug store and grocery store but all I can find is 91% and 70% isopropyl alcohol. Do I have to buy 99% IPA over the net?

author: magic
author_rank: Super Contributor
timestamp: October 05, 2021, 05:30:34 pm
content: You could try hardware store, electronics/maker/DIY shops if there are any, maybe computer stores (it's used to remove old thermal greases), chemical suppliers, ...

author: georges80
author_rank: Frequent Contributor
timestamp: October 05, 2021, 05:32:07 pm
content: Unlikely you'll find 99% (or better) at a drug store etc.I have an electronics supplier (Anchor Electronics, Silicon Valley), where I can buy the MG chemicals 99.9 off the shelf.If you have no such place locally, then yeah, just order it.https://www.amazon.com/MG-Chemicals-824-1L-Isopropyl-Alcohol/dp/B005DNQX3Cisn't crazy marked up.cheers,george.

author: testpoint1
author_rank: Frequent Contributor
timestamp: October 05, 2021, 05:44:59 pm
content: Quote from: Axtman on October 05, 2021, 05:07:47 pmyou can buy it from Ebay, much more, 99%

author: alpher
author_rank: Frequent Contributor
timestamp: October 05, 2021, 07:04:56 pm
content: Costco.

author: mariush
author_rank: Super Contributor
timestamp: October 05, 2021, 07:23:30 pm
content: Search for 97% or better.70% is for washing hands, kills stuff better than other concentrations.Veterinarians also stock isopropyl alcohol, but I wouldn't know the concentration. It's often used with horses so you can ask vet places, pharmacies, if you have no luck in other places.Acetone is also a very good solvent, which could be used instead of isopropyl alcohol. Just avoid pouring acetone over some plastics (ex capacitor sleeves) or over printed text - the acetone can take the ink out.

author: IanB
author_rank: Super Contributor
timestamp: October 05, 2021, 07:36:37 pm
content: Quote from: Axtman on October 05, 2021, 05:07:47 pmI used to get the MG Chemicals brand from Fry's, but since they went out of business I have no retail options left that I know of. You probably have to order it online if you don't have any electronics stores near you that would be similar to Fry's.On the other hand, the 91% version might be perfectly fine for cleaning. The IPA will be good for grease and flux, and the water content would help to dissolve salts and other water-soluble things such as flux additives.

author: helius
author_rank: Super Contributor
timestamp: October 05, 2021, 07:40:42 pm
content: 99.9% isopropyl is for cleaning optical and magnetic assemblies. It is not especially good as a flux remover (due to the ionic contaminants issue mentioned by IanB) and has particular problems with no-clean flux residues.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 05, 2021, 07:58:09 pm
content: Quote from: helius on October 05, 2021, 07:40:42 pmDo you have a problem with the decimal place? IanB suggested 91%.

author: Axtman
author_rank: Regular Contributor
timestamp: October 05, 2021, 08:07:08 pm
content: I will be using the 99% IPA to clean the flux, and other contaminants, from circuit boards and switch contacts. I belive Fluke and Tektronix recommend this procedure.I have used drugstore 91% IPA but found that it left a white residue after the alcohol evaporated. I then had to clean the white residue with distilled water. I am hoping with the 99% IPA that I can skip that step.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 05, 2021, 08:11:46 pm
content: Why do you think 99% IPA will be better than 91% at dissolving "salts?" That's illogical.

author: edfarrington93
author_rank: Contributor
timestamp: October 05, 2021, 08:23:47 pm
content: I read that the difference between them is water content. 99% being the purest you can get, it evaporates the fastest and is good for electronics since there is basically no water. 70% kills germs better because the higher water content keeps the alcohol on the target surface longer allowing the alcohol time to kill the germs, whereas 99% is basically useless for germs because it doesn't remain on the surface long enough.

author: mariush
author_rank: Super Contributor
timestamp: October 05, 2021, 08:32:56 pm
content: It's not about how long is stays, it's making it possible for the alcohol to enter cell walls and damage them, easier.Seehttps://munglobal.com.au/resources/knowledge-base/pathogens/why-70-isopropyl-alcohol-is-a-better-disinfectant-than-99-isopropyl-alcohol/quoting from it70% isopropyl alcohol kills organisms by denaturing their proteins and dissolving their lipids and is effective against most bacteria, fungi and many viruses, but is ineffective against bacterial spores (CDC, 2020).Use of the more concentrated solutions (99%) will result in almost immediate coagulation of surface or cell wall proteins and prevent passage of the alcohol into the cell. When the outer membrane is coagulated, it protects the virus or bacteria from letting through the isopropyl (Widmer and Frei, 2011). Thus the stronger solution of isopropyl is creating a protection for the germ from the antiseptic properties of isopropyl, rendering the virus or bacteria more resilient against the isopropyl alcohol. To put it simply, higher concentrations cause an external injury that forms a protective wall and shields the organism. Furthermore, 99% isopropanol evaporates very quickly which does not allow it to penetrate cell walls and kill bacteria, and therefore isn’t as good for disinfecting surfaces. In other words, it breaks down the outside of the cell before it can penetrate the pathogen.In comparison, a 70% isopropyl alcohol can effectiveness cross over the cell membrane, thereby attacking the entire cell and killing the bacteria (CDC, 2020). The benefits of using 70% alcohol areCoagulation of surface proteins proceeds at a slower pace, thereby allowing the alcohol to enter the cell.70% alcohol, being a dilution of absolute alcohol, contains water which is essential in the denaturing process of proteins.Due to the concentration difference of water and alcohol on either side of the cell wall, 70% alcohol enters the cell to denature both enzymatic and structural proteins. This increases the potency of its antimicrobial properties.The CDC recommends 70% for disinfecting one’s household and routine cleaning (CDC, 2020)

author: helius
author_rank: Super Contributor
timestamp: October 05, 2021, 08:44:02 pm
content: "Good for electronics"... most circuit boards manufactured today undergo aqueous cleaning. For specific components such as photoarrays, fiber optic launchers, or CdS sensors, avoiding water spots is very important (that's why I mentioned optical assemblies). For most electronics this doesn't matter at all, the only thing that matters is proper cleaning technique and a solvent strong enough to dissolve all residues. 91% isopropyl (the remainder is water) has acceptable performance on non-activated rosin flux. For most activated fluxes used today a stronger solvent mixture is desired, which can be achieved using a combination of alcohols, alkanes, ketones and esters. When formulated correctly the mixture remains plastic and soldermask safe.

author: BrokenYugo
author_rank: Super Contributor
timestamp: October 05, 2021, 09:49:12 pm
content: IIRC 99% turns to 91% quickly by picking up atmospheric water. Keeping alcohol "dry" is tricky.The white stuff (tin and lead oxides I think?) isn't terribly soluble in anything, solutions to the problem generally involve commercial purpose made flux removers, changing flux/solder, or simply leaving the rosin on the board.

author: Nusa
author_rank: Super Contributor
timestamp: October 05, 2021, 10:10:48 pm
content: There's a tradeoff between drying time and cleaning power. Higher concentrations dry faster, lower concentrations often clean better because there's more soak time.And yeah, it's hard to keep 99% stuff from absorbing moisture from the air unless you're religious about keeping the cap on tight. Plus you paid a lot more for that concentration.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 05, 2021, 10:43:10 pm
content: Quote from: BrokenYugo on October 05, 2021, 09:49:12 pmHere's Kester's study of the "white stuff:"https://www.kester.com/Portals/0/Documents/FAQs/White_Residue.pdfWithout more information (e.g., solder, flux, aging), it is speculative what the residue is.

author: Axtman
author_rank: Regular Contributor
timestamp: October 05, 2021, 10:58:33 pm
content: Only on the EEVblog forums can you ask a question about electronics and get medical advice!Thanks guys for your input.

author: IanB
author_rank: Super Contributor
timestamp: October 06, 2021, 05:42:14 am
content: Quote from: Axtman on October 05, 2021, 08:07:08 pmIt doesn't matter what concentration you use if you let the solvent evaporate, since once the solvent evaporates it will leave behind anything that was dissolved in it.The key to effective cleaning is to rinse properly. Rinsing carries away dirt and contaminants leaving clean surfaces behind. If you don't rinse, you have not removed the dirt. (The same applies when washing hands, clothes, dishes, cars, and most anything else.)

author: Axtman
author_rank: Regular Contributor
timestamp: October 06, 2021, 02:23:56 pm
content: I have been using 91% IPA in a spray bottle. It works well if I need clean a whole board and don't want to soak or pour the IPA. I can spray a small area if I am careful. For really small areas I use a Q-tip soaked in IPA.https://www.riteaid.com/shop/ra-trggrspry-alchl-91-10z-0358266

author: Jeroen3
author_rank: Super Contributor
timestamp: October 06, 2021, 02:33:03 pm
content: Not all contaminants dissolve in alcohol, and not all dissolve in water.It has something to with polar molecules and stuff. I'm no chemist, he is:70% works best for typical cleaning and degreasing, just get that.

author: ve7xen
author_rank: Super Contributor
timestamp: October 06, 2021, 07:00:56 pm
content: Does anyone know what the reason is for the lack of availability of 99% in so many places? Pretty much any drug store here carries it for cheap (like < $5 for 500ml) and it's easy to find. Even the local grocery store (which does not have a pharmacy) was carrying it at the beginning of the pandemic alongside the 70%, though not sure if they've kept that up. Is there some sort of regulation or what?

author: Kleinstein
author_rank: Super Contributor
timestamp: October 06, 2021, 09:48:11 pm
content: One rarely needs the 99% pure IPA. When used in normal humdity air, it will capture water quite fast while using it on the PCB.Purity can still be important, but it is not about the water, but about other part in there. Some are bad (e.g. hardly soluble parts, like platicizer deissolved from the bottle, traces of silicone) and some don't really matter (e.g. water or ethanol) for the more normal cleaning jobs. 99.9% IPA with 0.1% silicone is pretty ugly. 90% IPA with 10% water could be pretty good.

author: notsob
author_rank: Frequent Contributor
timestamp: October 06, 2021, 10:54:39 pm
content: Try looking for a dedicated supplier, like this one in AUShttps://www.sydneysolvents.com.au/

author: Bassman59
author_rank: Super Contributor
timestamp: October 07, 2021, 02:15:44 am
content: Quote from: Axtman on October 05, 2021, 05:07:47 pmIn the US? The local Ace Hardware stores should carry it.

author: David Hess
author_rank: Super Contributor
timestamp: October 07, 2021, 03:02:05 am
content: If you can find 91% IPA for a good price, then you could remove the water with a desiccant before you use it.

author: retro_gamer
author_rank: Contributor
timestamp: October 07, 2021, 04:53:43 am
content: I really like these aerosol cans from MG chemicalshttps://www.tequipment.net/MG-Chemicals/824-450G/Cleaning-Fluids,-Degreasers/?v=0

author: antenna
author_rank: Frequent Contributor
timestamp: October 07, 2021, 06:47:20 am
content: I typically use 91% IPA, then blast the moisture out from under components with a can of carburetor cleaner followed by distilled acetone then evaporating that off with compressed air. I think the white residue from IPA is the bittering agent added to deter consumption and hardware store acetone has additives too, probably to interfere with TATP synthesis.I don't know what everyone else uses for electronics flux, but the only thing I've ever used was the plumbing isle paste flux with zinc chloride, ammonium chloride and petrolatum. Getting that stuff out from under SMD's is a pain! I can't count all the projects I tossed out that would have worked fine had I cleaned them better. I definitely need to be using something else for flux.I've heard isoamyl or isopropyl nitrite removes almost everything including teflon grease, not good for blood pressure though

author: Kleinstein
author_rank: Super Contributor
timestamp: October 08, 2021, 09:37:48 pm
content: There is same danger to damage parts with aceton. Unless really needed for some greasy stuff, I would avoid it. Even if no damage visible it can make quite some plastics swell and over time this leads to drift when the aceton slowly escapes the plastics.For the white residue, there is an interesting link, just a few answers backhttps://www.eevblog.com/forum/repair/where-can-i-buy-99-isopropyl-alcohol/msg3731062/#msg3731062.It is definitely not a question of cleanness of the IPA - additives for denaturation are also liquid and hard to remove. So they don't leave behind. The trouble some parts are more grease / way like parts from the flux and some salts (e.g. PbC03) with low solubility. For the salty parts IPA would not help - the lower the purity the better (e.g. look for 1 % concentration). Here it is more like lots of hot water and maybe some mild acid (to convert carbonates). If at alle the purity matters for the very last rinse, when it already looks clean. Clean solvents don't come in a plastic bottle, but in glass or metal cans.The plumbers flux is often hard to remove and the residue can be corrosive. For very easy cleaning one can use glycerin as a flux, cleans off with water easy, just give quite some fumes.

author: David Hess
author_rank: Super Contributor
timestamp: October 09, 2021, 02:32:41 am
content: Quote from: Kleinstein on October 08, 2021, 09:37:48 pmLacquer thinner works better than acetone, but has the same issue with damaging some plastics. Toluene works, but will also damage some plastics, which is a shame because 50/50 IPA and toluene is an excellent solvent for flux. I have some boards built in the 70s which I cleaned with just water and dish-soap in my ultrasonic cleaner and it removed the markings from the ICs.We used to clean the boards with an aggressive solvent before mounting more sensitive parts which would be damaged by the flux cleaner, especially DIP switches. Boards with precision circuits, microvolts and picoamps and high impedance circuits, need to have special cleaning procedures.Naphtha is very safe for plastics but perhaps not for dissolving flux residue, and it isn't miscible with water. I knew one place that used amyl acetate for cleaning.After rework, I clean boards with cotton swabs and lacquer thinner.

author: Psi
author_rank: Super Contributor
timestamp: October 09, 2021, 03:46:58 am
content: Anyone with a SLA 3D printer buys lots of isopropyl alcohol, maybe ask around with any local places that sell SLA printers where they recommend getting it from.

author: beanflying
author_rank: Super Contributor
timestamp: October 09, 2021, 03:50:44 am
content: Quote from: ve7xen on October 06, 2021, 07:00:56 pmCOVID in a large part was to blame at least here in Oz. The assclowns wiped out any and all availability of Toilet Paper and Alcohol in the hope of making a $. The were buying up all store and online supplies of 'pure' and diluting it to 70% then loading it up to resell. None of the local Chemists in most cases stocked anything better than 70%. While all this dumbassery was going on if you wanted a 200L drum then all the manufacturers of IPA still had some with minimal issues.We have been back to normal (whatever that is) and I have gone back to buying my Acetone and 99% IPA from a Hair Care / Beauty supplier I have used for years. For me cheap postage to where I live is important and 1L at a time is plenty.

author: jonpaul
author_rank: Super Contributor
timestamp: October 09, 2021, 04:41:02 am
content: Amazon sells gallons for $80-100 with shipping incl.We found that ordering the gallon in pint bottles is much more convenient to reduce rebottling and evaporation/dilution.The 99% leaves virtually no residue.A gallon is a lifetime supply.Jon

author: JDubU
author_rank: Frequent Contributor
timestamp: October 09, 2021, 06:37:38 am
content: This:https://www.amazon.com/MG-Chemicals-824-1L-Isopropyl-Alcohol/dp/B005DNQX3C/ref=sr_1_1?dchild=1&keywords=0779008824139&qid=1633761400&sr=8-1

author: retro_gamer
author_rank: Contributor
timestamp: October 09, 2021, 11:07:49 pm
content: I've been able to get gallons of 99.9% technical grade alcohol from hydroponics shops for ~$20. They sell it there for people to clean their watering systems and scissors, etc. Worth checking out before spending $100 on Amazon.

author: Nusa
author_rank: Super Contributor
timestamp: October 09, 2021, 11:47:18 pm
content: If you can get it local retail, usually that's cheaper. A good chunk of the mail-order price is the cost of shipping highly-flammable hazardous liquids.

author: Maniac303
author_rank: Newbie
timestamp: October 10, 2021, 12:16:34 am
content: If you can't find it at your local hardware store or beauty supply outlet, try a store that specializes in fibre-glass / epoxy, resins and the like. They sell it in 4 litre (1 gallon) jugs and 18 litre (5 gallon) barrels at a fraction of the price of your electronics store.If they sell 'Smooth-On' products, they will sell solvents. Some more exotic than IPA.

author: BBBbbb
author_rank: Unknown
timestamp: October 10, 2021, 09:47:25 am
content: Quote from: Maniac303 on October 10, 2021, 12:16:34 amThis^Unless your local electronic shop has it, try the cosmetic shops (but those selling to salons), for some reason they sell 99.9%, and these days they are more common than local electronic shops.And as few already mentioned, take care about capturing atmospheric water and lowering that %, i.e. don't keep it open while working.Still 99% seems like a purity overkill for PCB cleaning. I use it for optics and there you can see small water stains once it "captured" too much water.

author: edfarrington93
author_rank: Contributor
timestamp: October 19, 2021, 02:42:33 pm
content: https://www.amazon.com/MAXTITE-MaxTite-Isopropyl-Alcohol-99-9/dp/B08CGJV5FR?th=1This is what we buy at work.

author: WaynesWorld
author_rank: Contributor
timestamp: October 20, 2021, 11:36:23 am
content: In Australia - Radio Parts or Altronics.

author: Renate
author_rank: Super Contributor
timestamp: October 21, 2021, 08:35:09 pm
content: I just use the 91% IPA that you can buy at any dollar store int the US.I find it more important to let the IPA dissolve stuff, then blot it with paper towels to remove the contaminated solvent than to let it dry and re-deposit itself.Of course, in many places you can just buy "Everclear", 95% ethanol which is dual-prupose when work is over.

author: IanB
author_rank: Super Contributor
timestamp: October 22, 2021, 02:52:56 am
content: Quote from: Renate on October 21, 2021, 08:35:09 pmExcept California

author: lunacyworks
author_rank: Contributor
timestamp: October 24, 2021, 09:25:38 am
content: Try microcenter, this is the brand I use to buy from them in California before they closed, And frys carried it before they also closed.https://www.microcenter.com/product/451968/puretronics-technical-grade-isopropyl-alcohol-999-32ozI will be ordering some soon as mine is about gone.

author: David Hess
author_rank: Super Contributor
timestamp: October 26, 2021, 02:16:34 am
content: Quote from: IanB on October 22, 2021, 02:52:56 amReally? I would not have guessed that California had restricted Everclear. It is pretty expensive but even I have a couple bottles, for medicinal purposes of course.

author: IanB
author_rank: Super Contributor
timestamp: October 26, 2021, 02:48:43 am
content: Quote from: David Hess on October 26, 2021, 02:16:34 amCalifornia tends to go for regulatory overkill. The Everclear sold here is diluted to 60%.California has also banned various kinds of solvents due to air pollution (VoCs), and has just enacted a law that will ban the sale of small internal combustion engines as found in lawn mowers, leaf blowers, chain saws, portable generators, and the like.

author: David Hess
author_rank: Super Contributor
timestamp: October 26, 2021, 03:01:57 am
content: Quote from: IanB on October 26, 2021, 02:48:43 amI am aware of California's zealous regulatory and prohibitive legal culture. I used to live there. Not long before I left, they were regulating the smell of rising bread from bakeries. I used to work about 2 blocks from a Laura Scudder potato chip factory, and it was the smell of heaven.I would really like to know what they expect portable generators to be replaced with. I guess it is more egalitarian if everybody suffers in the dark during rolling blackouts, or at least poor people.

author: Bud
author_rank: Super Contributor
timestamp: October 26, 2021, 05:33:39 am
content: Can you fart in California?

author: metertech58761
author_rank: Frequent Contributor
timestamp: October 27, 2021, 02:16:05 am
content: When I worked as a meter tech, all the vans had one or two bottles of DLX brand fuel line de-icer, which was actually 99% isopropyl.Dunno if it's still produced or if other fuel de-icers are also 99% isopropyl, but thought I'd just put that out there.

author: dirtcooker
author_rank: Regular Contributor
timestamp: January 06, 2022, 03:25:43 pm
content: I have purchased IPA from here:http://www.dudadiesel.com/choose_item.php?id=isoprop