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Using Arduino => General Electronics => Topic started by: firashelou on Sep 27, 2015, 02:34 pm

Title: Is it possible to clean ICs with Pure Alcohol ?
Post by: firashelou on Sep 27, 2015, 02:34 pm
hello guys,
i hope you all having a great weekend
i would like please to know if it is possible to clean the ICs chips from dust with pure Alcohol ?
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: weedpharma on Sep 27, 2015, 02:37 pm
I have used isopropyl alcohol without problems.

Weedpharma
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: firashelou on Sep 27, 2015, 02:49 pm
I have used isopropyl alcohol without problems.

Weedpharma
aha a more than 90%
well mine is 95% but it says Aqua and Alcohol so it has to be ethanol as google search showed
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: aarg on Sep 27, 2015, 03:12 pm
aha a more than 90%
well mine is 95% but it says Aqua and Alcohol so it has to be ethanol as google search showed
Highly unlikely. The sale and labelling of such products are tightly regulated.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: firashelou on Sep 27, 2015, 03:15 pm
Highly unlikely. The sale and labelling of such products are tightly regulated.
what do you mean ? i did not understand what you mean ?

i just put some pure alcohol in a cup and i threw the Shift registers 959 inside and after a while i took them off and cleaned them with a small towel and now leaving it to dry a little
is that a good procedure to do or it will have a negative impact on the ICs ?
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: aarg on Sep 27, 2015, 03:34 pm
what do you mean ? i did not understand what you mean ?

i just put some pure alcohol in a cup and i threw the Shift registers 959 inside and after a while i took them off and cleaned them with a small towel and now leaving it to dry a little
is that a good procedure to do or it will have a negative impact on the ICs ?
Alcohol will not damage the IC's. For your own health, treat it as a toxic chemical.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: firashelou on Sep 27, 2015, 08:57 pm
Alcohol will not damage the IC's. For your own health, treat it as a toxic chemical.
ah ok gd because i cleaned the ICs with it
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Boardburner2 on Sep 27, 2015, 09:11 pm
hello guys,
i hope you all having a great weekend
i would like please to know if it is possible to clean the ICs chips from dust with pure Alcohol ?
depends on the alcohol

isppropyl alcohol  can work

Ethanol is subject to duty and very expensive.

Meths is a mixture of mostly ethanol and methanol to make it undrinkable methanol is very poisonous.

Meths contains an emetic to discourage you.

what do you want to clean off ?
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: firashelou on Sep 27, 2015, 09:45 pm
depends on the alcohol

isppropyl alcohol  can work

Ethanol is subject to duty and very expensive.

Meths is a mixture of mostly ethanol and methanol to make it undrinkable methanol is very poisonous.

Meths contains an emetic to discourage you.

what do you want to clean off ?
i am cleaning dust
the bottle i have doesn't say ! it says Pure Alcohol
and about the compositions it says : Aqua and Alcohol
that's all :/
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Boardburner2 on Sep 27, 2015, 10:55 pm
deonised or distilled water should work for that depending what the dust is and you thouroughly dry it.
does nnot an air blast work ?
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: firashelou on Sep 27, 2015, 11:16 pm
deonised or distilled water should work for that depending what the dust is and you thouroughly dry it.
does nnot an air blast work ?
i dont have one,
i have the normal hair dryer which won't work

but anyway what i did is take a cup put some pure alcohol the one you can use on injuries or for cleaning and put some in the cup and after i threw the shifts inside and then take them out and dry it with tissue and left it to fully dry in the normal air
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Paul__B on Sep 28, 2015, 08:18 am
Meths is a mixture of mostly ethanol and methanol to make it undrinkable methanol is very poisonous.
Well, somewhat (https://en.wikipedia.org/wiki/Methanol#Toxicity) poisonous.  The amounts cited are moderately difficult to ingest. :smiley-eek:

Meths contains an emetic to discourage you.
Not usually.  Generally a bitterant (https://en.wikipedia.org/wiki/Denatonium)and possibly odorant (https://en.wikipedia.org/wiki/Pyridine).
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Boardburner2 on Sep 28, 2015, 10:46 am
There are fair few tourists who have bought cheap alcohol when travelling who would thoroughly disagree with that, a no of doctors as well.

In any case whatever the additive i find my local stuff leaves a residue so probably best not used for pcbs.

I'm not quite sure of the difference between a bitterent and an emetic but i'm not about to try and find out.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: weedpharma on Sep 28, 2015, 10:57 am
A bitterent make it nasty to ingest while an emetic make it easy to eject!   :)  :)  :)

Weedpharma
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Boardburner2 on Sep 28, 2015, 11:25 am
grin.

As an addendum , industrial meths is an excellent solvent imo.

It does not have the residue associated with the over the counter.

Unfortunately eu taxation of alcohol encourages adulteration by criminal gangs and poisoning is too common.

This makes industrial meths extremely difficult to get.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: aarg on Sep 28, 2015, 12:26 pm
I thought ethyl and methyl had a different carbon chain. Methyl = CH4O and ethyl = C2H6O.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: russellz on Sep 28, 2015, 12:39 pm
grin.

As an addendum , industrial meths is an excellent solvent imo.

It does not have the residue associated with the over the counter.

Unfortunately eu taxation of alcohol encourages adulteration by criminal gangs and poisoning is too common.

This makes industrial meths extremely difficult to get.
Here, in France, you can buy "Alcool à brûler" in any supermarket.  It consists of 90 to 95% ethanol with 5 to 10% methanol.  Both are highly volatile and leave no residue making it very good for cleaning.

Russell.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Boardburner2 on Sep 28, 2015, 01:13 pm
equivalent here is rubbing alcohol.
Composition is different though its pretty good but im sure that there is something else in it , it feels slightly oily after evaporation

The french type cannot be imported to the uk without a licence, i tried once.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Paul__B on Sep 28, 2015, 02:02 pm
Composition is different though its pretty good but im sure that there is something else in it , it feels slightly oily after evaporation
That would be because it has oil in it!

And often, perfume as well.

Hint:  Notice the name: "Rubbing Alcohol." :smiley-roll:
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Boardburner2 on Sep 28, 2015, 02:07 pm
i am cleaning dust

and about the compositions it says : Aqua and Alcohol

Aqua i think is water according to cosmetic companies.

Alcohol type should be specified.

Over here rubbing alcohol uses isopropyl alcohol at 40 % as a denaturant.

Its not very nice for dust ime it evaporates slowly and sludges the dust making it difficult to vacuum.

Cleaning dust off psu's especially hv ones can be very annoying.

Not allowed to use compressed air as it blows it all over the place  just a hoover.

industrial meths (brushed with adequate ventilation) used to be my preferred solution.

Cant have water in it.

Someone suggested colemans fluid but iv never been sure about that to try it.

edit
to be clear i was using pure isopropyl not rubbing alcohol.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Paul__B on Sep 28, 2015, 02:18 pm
Aqua i think is water according to cosmetic companies.
Actually, it is according to the classical Romans of antiquity who developed the language: Latin.  Traditionally used in the Medical Profession and pharmaceutical products.

Over here rubbing alcohol uses isopropyl alcohol at 40 % as a denaturant.
Its not very nice for dust ime it evaporates slowly and sludges the dust making it difficult to vacuum.
If IPA is the "denaturant", what is the rest?  Ethanol I suppose, as it is the cheapest to actually make.

"Rubbing alcohol" sludges the dust because as noted above, it contains oil.

Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Boardburner2 on Sep 28, 2015, 02:33 pm
Actually, it is according to the classical Romans of antiquity who developed the language: Latin.  Traditionally used in the Medical Profession and pharmaceutical products.
If IPA is the "denaturant", what is the rest?  Ethanol I suppose, as it is the cheapest to actually make.

"Rubbing alcohol" sludges the dust because as noted above, it contains oil.


Yes ethanol and isopropyl.

Oil, yes i edited the post while you were posting , i was meaning pure isopropyl not rubbing.

Manufacturer says alcohol can be used without specifying type.

In the good old days we had arklone available.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: CrossRoads on Sep 28, 2015, 03:24 pm
Anhydrous alcohol works well, 99.9%. Dries quick thru evaporation as there is next to nothing in it. Use ventilation if cleaning a lot of cards.
http://www.mgchemicals.com/products/cleaners/electronic-cleaners/isopropyl-alcohol-824/ (http://www.mgchemicals.com/products/cleaners/electronic-cleaners/isopropyl-alcohol-824/)
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: DrAzzy on Sep 28, 2015, 05:15 pm
I've never seen "rubbing alcohol" that had crap in it, it always evaporated clean for me. At least in the states, rubbing alcohol is 70% or 91% (the stood you want) isopropyl alcohol. It does not contain a denaturant, as isopropyl alcohol is not drinkable (it's only mildly toxic though).

That's what I use for cleaning off flux, as well as many other cleaning operations
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: firashelou on Sep 28, 2015, 05:33 pm
Here, in France, you can buy "Alcool à brûler" in any supermarket.  It consists of 90 to 95% ethanol with 5 to 10% methanol.  Both are highly volatile and leave no residue making it very good for cleaning.

Russell.
exactly mine is volatile that's why i had courage to use it ! you can put alcohol all over yourself and after a bit of time nothing is left :)
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: firashelou on Sep 28, 2015, 05:39 pm
Aqua i think is water according to cosmetic companies.

Alcohol type should be specified.

Over here rubbing alcohol uses isopropyl alcohol at 40 % as a denaturant.

Its not very nice for dust ime it evaporates slowly and sludges the dust making it difficult to vacuum.

Cleaning dust off psu's especially hv ones can be very annoying.

Not allowed to use compressed air as it blows it all over the place  just a hoover.

industrial meths (brushed with adequate ventilation) used to be my preferred solution.

Cant have water in it.

Someone suggested colemans fluid but iv never been sure about that to try it.

edit
to be clear i was using pure isopropyl not rubbing alcohol.
aqua is latin yes and it means water for sure, it is used in italian and spanish but different letters, in spanish acqua and in italian agua

well i tried to clean the ICs as i said before and everything works fine, the composition doesn't tell which alcohol they are using but it says the percentage is 95% that's all on the bottle
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: firashelou on Sep 28, 2015, 05:41 pm
Anhydrous alcohol works well, 99.9%. Dries quick thru evaporation as there is next to nothing in it. Use ventilation if cleaning a lot of cards.
http://www.mgchemicals.com/products/cleaners/electronic-cleaners/isopropyl-alcohol-824/ (http://www.mgchemicals.com/products/cleaners/electronic-cleaners/isopropyl-alcohol-824/)

the one i use cleans 99.9% too and dries very quickly so i guess according to this info my ICs are safe :) ?
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: jboyton on Sep 28, 2015, 06:52 pm
Is there really an advantage in using 99.9% isopropanol vs. the 91% solution that is readily available? A 91% v/v solution is the azeotrope. A nearly pure solution would be somewhat more volatile but temperature and air flow are probably a lot more important than that slight difference. I wonder how much moisture the anhydrous stuff absorbs before it evaporates?

Anhydrous isopropanol costs $10 for a 500ml bottle at digikey, not including shipping. The other day I walked down to the local drug store and bought a 480ml bottle of 91% isopropanol/water for under $3.

Or does it make a noticeable difference?
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: CrossRoads on Sep 28, 2015, 07:12 pm
I find the "dryer" alcohol cuts thru the flux from rosin core solder quite well. Lesses %s need multiple passes to clean.
My local electronics supplier has it in gallon bottles. I picked one up at some point, we put a few  ounces at a time in a small pump jar (not sure what the actual name is, same square bottle with spring top, push down a couple times and top fills with some alcohol for the cleaning brush - same thing our shop at work uses for cleaning up reworked boards).
http://www.mouser.com/ProductDetail/Menda/35309/?qs=%2fha2pyFadugResYH%252b75ZqvYV6knOqbetNdKoUVscgdY%3d (http://"http://www.mouser.com/ProductDetail/Menda/35309/?qs=%2fha2pyFadugResYH%2b75ZqvYV6knOqbetNdKoUVscgdY%3d")
which my supplier also had, along with a hog hair bursh
http://www.mouser.com/ProductDetail/MG-Chemicals/857/?qs=sGAEpiMZZMvJqaFk9BIiv6jhjM0Pk6JzPq2RhIeIS6c%3d (http://"http://www.mouser.com/ProductDetail/MG-Chemicals/857/?qs=sGAEpiMZZMvJqaFk9BIiv6jhjM0Pk6JzPq2RhIeIS6c%3d")
This one works well as the bristles are longer and the pins of shields can go thru the bristles.
Hopefully the forum/IE11 won't stick extra http stuff at the front of the links ...
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: CrossRoads on Sep 28, 2015, 08:10 pm
Good stuff! Use in a ventilated area.

ISOPROPYL ALCOHOL: ELECTRONICS CLEANER 824-LIQUID

Page 10 of 14 Date of Creation: 01 Aug 2013 / Ver. 2.01

Skin corrosion/irritation

Causes mild skin irritation based on Draize tests on rabbits. Prolonged or repeated skin contact may cause dermatitis

Serious eye damage/irritation

Causes moderate to severe eye irritation based on Draize tests on rabbits

Sensitization (allergic reactions)

No evidence of sensitization

Carcinogenicity (risk of cancer)

Not classified or listed as a carcinogen by IARC, ACGIH, CA Prop 65, or NTP

Mutagenicity (risk of heritable genetic effects)

No data available

Reproductive Toxicity (risk to sex functions)

No data available

Teratogenicity (risk of fetus malformation)

No data available

STOT-single exposure

Propan-2-ol can affect the central nervous system by inhalation causing drowsiness or dizziness.

STOT-repeated exposure

No data available

Aspiration hazard

Not classified as aspiration hazards.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: jboyton on Sep 28, 2015, 09:10 pm
So you think the 99% concentration has a noticeably greater solvent power than the 91%? It would be interesting to see a blind test.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: CrossRoads on Sep 28, 2015, 09:15 pm
I just know it took what seemed like 3 cleanings for the sticky feel to go away, and longer to dry.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: polymorph on Sep 29, 2015, 06:08 pm
Quote
Here, in France, you can buy "Alcool à brûler" in any supermarket.  It consists of 90 to 95% ethanol with 5 to 10% methanol.  Both are highly volatile and leave no residue making it very good for cleaning.
equivalent here is rubbing alcohol.
Composition is different though its pretty good but im sure that there is something else in it , it feels slightly oily after evaporation

The french type cannot be imported to the uk without a licence, i tried once.
Incorrect. "Rubbing Alcohol" is isopropyl, water, and generally some kind of oil.

What he describes is called denatured alcohol in the USA. Ethanol with methanol and often a few other solvents. Works great as a degreaser, but attacks some plastics.

I generally use 99% isopropyl for cleaning electronics, but also use denatured alcohol for some tasks.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: polymorph on Sep 29, 2015, 06:08 pm
So you think the 99% concentration has a noticeably greater solvent power than the 91%? It would be interesting to see a blind test.

The key thing is that it leaves less water behind.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: jboyton on Sep 29, 2015, 07:59 pm
The key thing is that it leaves less water behind.
The solution doesn't evaporate?
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: polymorph on Sep 29, 2015, 09:08 pm
The alcohol evaporates quickly, the water not as quickly.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: jboyton on Sep 29, 2015, 10:23 pm
Not for a 91% solution. The vapor and liquid have the same composition. That's why it's impossible to obtain a higher concentration via simple distillation. I think that also means it is slightly more volatile than pure isopropanol. The 91% stuff should actually evaporate as fast or a little faster.

But maybe the higher concentration makes it a better solvent.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: polymorph on Sep 30, 2015, 02:06 am
Citation?

But... the 99% starts out with less water in it. So even if the alcohol evaporates more quickly, it reaches dynamic equilibrium at 91% and continues to evaporate at 91%, but it has reached that point more quickly.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: JoeN on Sep 30, 2015, 02:54 am
This is what I use.  Get it at Fry's or online, or seek a similar alternative.

I agree with Crossroads.  It usually takes 3 cleanings to get rosin flux "perfectly" cleaned off.  However, you don't need it perfect unless you are selling it or showing it to investors.  Once is pretty good.

(http://forum.arduino.cc/index.php?action=dlattach;topic=349827.0;attach=139271;image)
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: jboyton on Sep 30, 2015, 03:08 am
Citation?

But... the 99% starts out with less water in it. So even if the alcohol evaporates more quickly, it reaches dynamic equilibrium at 91% and continues to evaporate at 91%, but it has reached that point more quickly.
I don't have a citation. And my chemistry is pretty poor.

This is from wikipedia (https://upload.wikimedia.org/wikipedia/commons/f/fa/VLEIsoropanolWaterAzeotrope.png):

(http://s7.postimg.org/coh3kvz17/VLEIsoropanol_Water_Azeotrope.png)

The azeotrope is at a mole fraction of about 0.68. The molecular weights of isopropanol and water are 60.1 and 18.0 g/mol respectively. So the weight fraction of isopropanol at the azeotrope is approximately:

(0.68*60.1) / (0.68*60.1 + (1-0.68)*18.0) = 0.88

Converting that to volume is more complicated because there is contraction upon mixing. But if you ignore that you can get sort of close. The room temperature densities of isopropanol and water are 0.79 and 1.00g/cm3, so:

(0.88/0.79) /(0.88/0.79 + (1-0.88)/1.00) = 0.90

My seat of the pants calculation puts the azeotrope at 90% v/v. But that can't be right since the drug store sells isopropanol/water at 91%. The volume contraction or my inaccurate read of the chart in wikipedia have thrown off the value slightly.

I'm surprised it's so hard to find an online reference to the v/v percentage. But here's one (https://books.google.com/books?id=Q6XFfg8IIuAC&pg=RA1-PA415&lpg=RA1-PA415&dq=91%25+azeotropic+mixture+isopropyl+alcohol&source=bl&ots=AbQHbgopG0&sig=R-s6T1PD5JAkTdeCZuevBeCFj00&hl=en&sa=X&ved=0CBwQ6AEwA2oVChMIi4PcwMadyAIVVTKICh3URgRT).

You can't distill past the azeotrope using normal methods. But if you manage to get to a higher concentration by other means then the solution will have a vapor that is enriched in the less volatile component. That is, the water will vaporize faster than the alcohol in a 99% isoprop. soln.

But the azeotrope is a boiling point minimum; hence a vapor pressure maximum. So evaporation rate would be higher for the less concentrated stuff. I'm not convinced this matters that much. And eyewitness accounts of evaporation rate are subject to bias.


All that said, it could well be that pure isopropyl alcohol is superior to a 91% mixture, I really don't know. I wouldn't be surprised if some other solvent would be better overall for cleaning the gunk off of PCBs.

Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: JoeN on Sep 30, 2015, 03:21 am
I wouldn't be surprised if some other solvent would be better overall for cleaning the gunk off of PCBs.
There are specific formulations for that.  At least the manufacturers think they are better.  They are certainly a bit more expensive than alcohol though.  OP could give this a try and get back to us.  Fry's sells it also.

http://www.all-spec.com/products/4140-1L.html (http://www.all-spec.com/products/4140-1L.html)

(http://forum.arduino.cc/index.php?action=dlattach;topic=349827.0;attach=139273;image)
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: larryd on Sep 30, 2015, 03:28 am
The MSDS says:

(http://forum.arduino.cc/index.php?action=dlattach;topic=349827.0;attach=139275)

They will be selling air next.

.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: jboyton on Sep 30, 2015, 04:03 am
The composition of the 4140 flux remover varies by country. But ethanol seems to be the main ingredient. That's kind of interesting. I asked about that in another thread, whether ethanol had any advantages/disadvantages for cleaning as compared to IPA.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: JoeN on Sep 30, 2015, 04:27 am
Maybe I will pick up a bottle of it next time at Fry's and do a blind scrub-off test.  :)
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: dmjlambert on Sep 30, 2015, 06:04 am
Everclear works best, and a big bottle of that goes a very long way for cleaning parts.   Works great, leaves no residue.   Not toxic unless you really drink more than a few swigs. 
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: JoeN on Sep 30, 2015, 06:17 am
Everclear works best, and a big bottle of that goes a very long way for cleaning parts.   Works great, leaves no residue.   Not toxic unless you really drink more than a few swigs.
I wouldn't be surprised at all if it worked great, but I see a price of about $17 per 750ml so it makes it a bit more expensive than the MG isoproponol I linked which is about $12 per liter, though it does have the advantage of being "multi-purpose". :)
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Boardburner2 on Sep 30, 2015, 12:07 pm
Incorrect. "Rubbing Alcohol" is isopropyl, water, and generally some kind of oil.

What he describes is called denatured alcohol in the USA. Ethanol with methanol and often a few other solvents. Works great as a degreaser, but attacks some plastics.

.
Currently the same here in the uk.
Historically not so, ipa as a denaturant is relatively new.

When moving in 1966 i inherited a large bottle of surgical spirit from the previous elderly owner.
That was ethanol and methanol but i do not know the percentages.

The use of methanol as a denaturant in the likes of cosmetic products was disallowed only last year.

I generally use 99% isopropyl for cleaning electronics, but also use denatured alcohol for some tasks.
Exactly ,  i would like the same choice.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Boardburner2 on Sep 30, 2015, 12:57 pm
Not for a 91% solution. The vapor and liquid have the same composition. That's why it's impossible to obtain a higher concentration via simple distillation. I think that also means it is slightly more volatile than pure isopropanol. The 91% stuff should actually evaporate as fast or a little faster.

But maybe the higher concentration makes it a better solvent.

There is almost always a small amount of water in the ethanol component but it dries relatively quickly.

Anhydrous ethanol made by synthesis evaporates completely but the cooling effect can cause some condensation so there is no real advantage.
Title: Re: Is it possible to clean ICs with Pure Alcohol ?
Post by: Boardburner2 on Sep 30, 2015, 04:34 pm
In applying for a licence i discovered something else.

Rubbing alcohol.

The manufacturer can use pretty much what he likes provided certain minima are met.

Concentration can be 99% ethanol so long as approved analytical agent and denaturant is used.

The use of methanol for this application was stopped in 2014.

Makers seem to have stopped long ago though.

I suspect that 60/40 is down to minimising cost.

Bugbear is the msds, as manufacturers do not have to list all ingredients (secret formula) up to
a certain percentage (0.5 i think) provided certain provisions are met re toxicity.