Everyone's Favorite Solvent?

[JoeyP]

I tried denatured alcohol back when I had the electronics repair business and the methanol became hard to get. We found it damaged many plastics used in consumer electronics (I think due to the ethanol content) which made it unsatisfactory for our needs.

I wouldn't ever use it to clean plastic. I'd probably use naptha on plastic. Each solvent has its place.

[rdl]

Your comment got me wondering about methanol. I've been using "Denatured Alcohol" for a long time, and thought it was mostly methanol. I buy it from Home Depot by the gallon. Doesn't say on the can just what it is, but does say it contains methanol, so I thought it was mostly methanol. Just looked it up, and found that it's about 50% methanol, 50% ethanol and a little methyl isobutyl ketone.

Wow, what brand was this? I worked in the paint and coatings industry for 25 years and the lowest level of ethanol I remember seeing was around 80%. The basic definition of denatured alcohol is ethanol with some other stuff added, 50% methanol is unusual.

I tried denatured alcohol back when I had the electronics repair business and the methanol became hard to get. We found it damaged many plastics used in consumer electronics (I think due to the ethanol content) which made it unsatisfactory for our needs.

More than likely it was the denaturants that were added that caused your problems. These can be active solvents such as acetates or ketones which are very aggressive toward many plastics.

[JoeyP]

Wow, what brand was this? I worked in the paint and coatings industry for 25 years and the lowest level of ethanol I remember seeing was around 80%. The basic definition of denatured alcohol is ethanol with some other stuff added, 50% methanol is unusual.

The brand is "Klean-Strip", but it's actually made by W. M. Barr. Here's a link to the MSDS:

http://engineering.case.edu/thinkbox/sites/engineering.case.edu.thinkbox/files/msds-1-denatured_alcohol.pdf

[N2IXK]

Chemically speaking, "denatured alcohol" is pretty meaningless. All it really means is ethanol, with enough of something else added to render it unfit for consumption.

That "something else" could be any number of different things, or combinations of them.  While methanol is one popular additive, it is certainly not the only one that can be used.  Here in the US, our government has a specific list of allowable formulations, some including diesel fuel, gasoline, pyridine, benzene, or formaldehyde. Yes, Uncle Sam would rather have you blind or dead than to let you get away with avoiding booze taxes! 

A complete list of formulations available here:

http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&sid=f7866313787bfcfb2b9cd25ba6af81b5&rgn=div5&view=text&node=27:1.0.1.1.17&idno=27#27:1.0.1.1.17.7.253.1

[Fsck]

Your comment got me wondering about methanol. I've been using "Denatured Alcohol" for a long time, and thought it was mostly methanol. I buy it from Home Depot by the gallon. Doesn't say on the can just what it is, but does say it contains methanol, so I thought it was mostly methanol. Just looked it up, and found that it's about 50% methanol, 50% ethanol and a little methyl isobutyl ketone.

Wow, what brand was this? I worked in the paint and coatings industry for 25 years and the lowest level of ethanol I remember seeing was around 80%. The basic definition of denatured alcohol is ethanol with some other stuff added, 50% methanol is unusual.

I tried denatured alcohol back when I had the electronics repair business and the methanol became hard to get. We found it damaged many plastics used in consumer electronics (I think due to the ethanol content) which made it unsatisfactory for our needs.

More than likely it was the denaturants that were added that caused your problems. These can be active solvents such as acetates or ketones which are very aggressive toward many plastics.

agreed. denatured alcohol is supposed to be ethanol primarily. The methanol and other denaturing additives are there to avoid the "alcohol" tax on consumable  alcohol.

[JoeyP]

I've never given a moment's thought about hurting the government's feelings over tax enforcement when choosing my favorite solvents. The 50/50 mix of ethanol/methanol that I can buy at Home Depot for around $25/gallon is a cheap,  excellent solvent for a lot of cleaning jobs

[David Hess]

The problem is not denatured alcohol but that it is not always clear what it is denatured with and the consumer grades may be contaminated with rather unsavory things at least as far as cleaning applications.  I have had problems with consumer grade isopropyl alcohol as well where it left film or deposits behind.  Taxed alcohol at least has the advantage of being suitable for consumption (I hope!) and therefor being "food grade" so it will not have kerosene, MEK, or benzine in it.

[tsmith35]

I buy 99% pure isopropyl alcohol (IPA) by the gallon from a nearby veterinary supply company. Cheap and works great.

Denatured alcohol typically contains (among other things) denatonium benzoate, one of the bitterest compounds around. Denatonium is the same stuff that's added to products that aren't meant to be consumed. It's so bitter that 10 parts per million is unbearably bitter to humans (per Wikipedia). It's in anti-licking spray used to keep pets from bothering wounds or infections.

[G7PSK]

I buy 99% pure isopropyl alcohol (IPA) by the gallon from a nearby veterinary supply company. Cheap and works great.

Denatured alcohol typically contains (among other things) denatonium benzoate, one of the bitterest compounds around. Denatonium is the same stuff that's added to products that aren't meant to be consumed. It's so bitter that 10 parts per million is unbearably bitter to humans (per Wikipedia). It's in anti-licking spray used to keep pets from bothering wounds or infections.

Denatonium benzoate is known as Bitrex in the UK ( http://www.bitrex.com/about-bitrex ) They put it in rat poison but the rats don't seem to mind they still eat it.
I had a friend who worked in the Cavendish laboratory in Cambridge, he used to analyse the glass washing alcohol as it came in if it was pure ethanol as it often was he would divert some of it to make gin. 

[zapta]

Such a long thread and nobody mentioned yet The Dip (a mix of turpentine acetone and benzene) so here it is.   ;-)

[rdl]

I'm just curious. I see a lot of references in this thread to benzene, is this what you are really using? The use of benzene (C6H6) pretty much ceased in the U.S. a long time ago (other than it's use as a precursor to other things) mainly because it became known that it was highly carcinogenic.

"it is generally considered that the only absolutely safe concentration for benzene is zero."

[N2IXK]

Probably some confusion between benzene (C6H6) and "benzine" which is a European (?) term for a mixture of hydrocarbon solvents akin to "naphtha" or "petroleum ether".

[tsmith35]

I've heard of using deionized water for cleaning circuit boards. Water is really my favorite solvent, right up there with ethanol...

[nanofrog]

I've heard of using deionized water for cleaning circuit boards. Water is really my favorite solvent, right up there with ethanol...

Do you make vodka out of mix them?   

Now where'd I put that orange juice.... 

[tsmith35]

It's customary to combine solidified water with ethanol. Additives are optional.

[CaptnYellowShirt]

It's customary to combine solidified water with ethanol. Additives are optional.

Carbonation helps too... also a twist of lime.

[tsmith35]

It's customary to combine solidified water with ethanol. Additives are optional.

Carbonation helps too... also a twist of lime.

That reminds me... d-limonene is a very, very effective solvent for removing inks, oils, adhesives and whatnot. It's commonly found in commercial "citrus degreaser".

Back at a previous job, we found that said citrus degreaser was actually more effective than xylene and other nasty chemicals at removing alcohol-based ink residue. Much safer, too, but wear gloves since it will strip the oil out of your skin.

[David Hess]

I've heard of using deionized water for cleaning circuit boards. Water is really my favorite solvent, right up there with ethanol...

Water that is deionized or distilled or produced by reverse osmosis is my first choice.  First I wash using a detergent like dish soap or TSP and then rinse.  It works great for removing contamination which is causing board leakage.  In extreme cases instead of scrubbing with a toothbrush, I use an ultrasonic cleaner and hot water for the wash stage.  Old assembled boards come out looking new.

I have seen dishwashers used for cleaning boards in production environments.

[nanofrog]

It's customary to combine solidified water with ethanol. Additives are optional.

Carbonation helps too... also a twist of lime.

I like how you guys think. 

Though for straight ethanol, I'd skip the solidified water, and opt for a few contaminants. Namely those found in a good single malt scotch. 

[tsmith35]

I like how you guys think. 

Though for straight ethanol, I'd skip the solidified water, and opt for a few contaminants. Namely those found in a good single malt scotch. 

So the conversation went from benzene to booze in a single page.

[nanofrog]

I like how you guys think. 

Though for straight ethanol, I'd skip the solidified water, and opt for a few contaminants. Namely those found in a good single malt scotch. 

So the conversation went from benzene to booze in a single page.

Of course! 

It's [ethanol] simply a solvent with additional uses.   

[N2IXK]

It's [ethanol] simply a solvent with additional uses.   

Yes, and while 91% IPA might be the one for cleaning, this IPA is much more entertaining at 18%....

http://www.beeradvocate.com/beer/profile/64/9086/