# Purest Brand of Isopropyl Alcohol?

#### intoxicated_pilot

Joined Feb 11, 2021
5
Is there any way to tell which brands of rubbing alcohol contain the least impurities (99% IPA of course)? Obviously this might help the longevity of the components/pcb that I clean it with.

Thanks!

#### SamR

Joined Mar 19, 2019
4,117
To begin with, there is a difference between Isopropyl alcohol and Rubbing alcohol which typically is made from 70% denatured ethanol and other ingredients. Which may include methlyisobutylketone, acetone, perfumes, coloring agents, witch hazel, mineral oil, etc. Isopropyl Alcohol to truly be pure would have USP on it's label. Read the label! For cleaning purposes you want 70% or better Isopropyl and the only other ingredient should be water and will say so on the label.

#### ErnieM

Joined Apr 24, 2011
8,271
Walmart's Equate brand of Iso is 91% pure with the remainder just water. It is in the pharmacy area intended as a wound sterlizer, but cleans boards too.

#### Janis59

Joined Aug 21, 2017
1,383
Once long ago in the completely another life I was often traveling to the 3000 km distant Sumi Electron-microscope factory. So, the object was semi-military and always the permission was made long before the trip, but always I am in the gates but they say, You must wait an hour or two until we shall form the ausweis. So, I am staying in the small gateway and from wild boring am reading the wall-papers what was imminent attribute of communist style. So, one is writing that she-worker of department thisandthat have won a communist job hero title etc etc and THEN! My attention was just glued to the page telling: Shame on the worker of unit suchandthat, who was cached that he was willingfully ADAPTED his organism for propanolic spiritus drinking. Later I told to some mates about so anecdotal wonder-man, and one mate who loved too much to booze told he once TRIED (just for experimentalist curiosity driven aim, with no any deeper idea behind, however I dont believe him much about the motives behind) one tea-spoon of isopropanol. He told the prime effect was so minor as from one droplet of ethanol, but the next three days only one thought was occupying whole the head - oh, let only I not die because of this foolish experiment. The next four days this thought was converted toward - Oh let I become died faster, its too inquisitive to take it so long. And then after week it laid him free. So... the biggest mystery is HOW that man was ADAPTING his body???

#### metermannd

Joined Oct 25, 2020
281
I have several bottles of 91% isopropyl I picked up from my local grocery store's drugstore section - brand is TopCare (the same stuff as the Equate brand mentioned above, different label). I find the 91% stuff is a LOT harder to find on the shelf vs. the normal 70% stuff... probably because of all the 'human malware' going around...

I also have a bottle of DLX brand fuel line deicer which may well be the 99% stuff (it just says: 'Contains Isopropyl alcohol' and no other ingredients are mentioned); when I worked as a meter tech, we had a a full box of these bottles in the shop and always had a bottle on hand in our vans.

#### Audioguru again

Joined Oct 21, 2019
4,523
I bought isopropyl alcohol rated at 99% and 1% water at a local drugstore. Its label says it can be an antiseptic or a solvent.
I would never clean something that has a rubbing oil in it.

Put some of your rubbing alcohol on a window to see how clean it makes it look.

#### SamR

Joined Mar 19, 2019
4,117
Put some of your rubbing alcohol on a window to see how clean it makes it look.
After using an alcohol prep swab for my weekly injection site I used it to "clean" my plastic lens glasses. I thought it had eaten the plastic there was so much crap after wiping. Luckily it was only the "other" ingredients in the alcohol prep swab that is left behind on the lenses!

#### kennybobby

Joined Mar 22, 2019
75
In the lab we use pure ethanol for cleaning boards and optics. it may cost more but avoids water. Industrial gallon containers with certs. For home use buy some PGA. If you tend toward being an alky then don't temp yourself, buy the poisionous version.

#### SamR

Joined Mar 19, 2019
4,117
If you tend toward being an alky then don't temp yourself, buy the poisionous version.
In my first college chem course, they used ethanol in the lab wash bottles. Curiously I asked the professor about it. He laughed and said "we make our own and denature it with phenolphthalein (active ingredient in laxatives used as a pH indicator in labs). That way when someone steals it they will only wish they were dead instead of dying."

#### kennybobby

Joined Mar 22, 2019
75
That's funny. Nice big ole cat you have there Sam.

Joined Jan 15, 2015
6,507
We bought all of our 99.9% isopropanol alcohol in 5 gallon containers from a chemical supply house. I would think any industrial chemical supply house would have it and any medical supply house should have it. A 5.0 USG container was between $250 to$300 USD and a 55 USG stainless steel drum was about \$750 USD plus. You can find small quantities online using Google. The reality is the common 70% you get at a local drug store or pharmacy will do just as well for your application as the 99% expensive stuff. Wash the pcb and allow adequate drying.

Ron